texts: Does diving after a take-off help gaining altitude?

texts:
I have often read fictions about aircraft, where a pilot does an action that I cannot explain:

During a takeoff with an heavy aircraft (four motors for example), the pilot rolls to the end of the airstrip, and starts to climb.
Then he says: I am too heavy to climb enough in order to avoid the mountain/trees/whatever obstacle in front of us.
So the pilot starts to dive to the ground in order to gain more speed, and then he climbs again and is able to have enough altitude.

How do you explain this action?

Considering the drag, why does the dive gain enough energy to go to an altitude above the one reach by the take off?

I might not be clear, please don't hesitate to ask details.
Here is a schema:

    Not enough         /Climb enough
        /  \          /
strip  /    \        /
              -------


texts: What are the FAA currency requirements for a foreign based certificate?

texts:
I hold a FAA private certificate that is issued based on 61.75. I have single engine land and instrument ratings on the foreign license (EASA). My FAA certificate also has these ratings listed.

My question now is: What are the currency requirements to execute the privileges of the FAA certificate to fly in the US?

61.75 (e) states:

  (3) Is subject to the limitations and restrictions on the person's U.S. certificate and foreign pilot license when exercising the privileges of that U.S. pilot certificate in an aircraft of U.S. registry operating within or outside the United States; and

This can be interpreted two ways:

a) The currency of a rating on the foreign license is a limitation or restriction and therefore the pilot needs to be current for both the foreign license (e.g. EASA 2 year check for SE land rating, and EASA 1 year check for instrument rating) in addition to the FAA required BFR and IPC/IR currency based on approaches etc.

b) The limitations and restrictions mean explicitly mentioned limitations (e.g. EASA PPL does not include night flying, so the US cert would have "VFR day only" listed as a restriction). The EASA license itself does not expire on its own and is valid as long as the pilot holds a valid medical. Therefore only the BFR and FAA instrument currency requirements apply to fly legally in the US.

So which interpretation is correct? Is there some other regulation which makes it more clear?

Practically "to be safe" I could just fulfill the EASA requirements every year/two years, but that is quite an effort (this can only be done by an EASA ATO which there are few in the US). It also adds additional costs.

I could also take the test(s) to get a FAA private and IR independently and everything would be FAA based only. That's an option but also requires time and effort.


texts: Does a constant speed prop deliver max speed at max manifold pressure and max RPM?

texts:
I was reading a discussion in flight simulator forum and I found this statement:

Ignoring the issue of engine overheating, max MAP and max RPM is the
best thing for max speed

Do you agree with that?
Assuming a Constant Speed Propeller.


texts: OBI, RMI, HSI... What combination do GA aircraft w/o glass typically have?

texts:
I'm learning about radionavigation, and all the various analog displays that can be used:

Automatic Direction Finder (ADF) - Provides basic bearing information to practically any radio source the pilot can tune to. Designed for use with the older NDB system developed during WWII, still in use but about two generations redundant in the face of VOR and GPS. Later models include a manual compass card to reduce mental math.
Radio-Magnetic Indicator (RMI) - A two-channel ADF with compass card slaved to the magnetic compass (or in some cases using an internal gyro like the Heading Indicator).
Omni Bearing Indicator (OBI) - Used for VOR navigation and the cheapest way to do so, has a manual compass card that selects the desired VOR radial and a CDI needle to provide a steering aid to place the aircraft on that radial, with a "TO/FROM" indicator to resolve directional ambiguity.
Horizontal Situation Indicator (HSI) - Combines the OBI with the aircraft's gyroscopic direction indicator to provide a simplified "moving map", with the aircraft's current heading, relative direction of the selected VOR radial, course deviation and glide slope all in one instrument. Can replace the Heading Indicator as well as an OBI to reduce instrument count and/or allow for redundant backups like a second artificial horizon. Biggest downside is cost (about $13k for the display unit itself).
Distance Measuring Equipment (DME) - essentially IFF in reverse; the aircraft interrogates a ground station with radio pulse pairs, and the station sends a matching pulse pair after a specially-timed delay; total round-trip time of the interrogation and response, minus the preprogrammed delay and halved, is the time the signal took to reach the station at the speed of light through air (about one nmi in 12.36 microseconds), which can then be used to calculate distance. These transponders are often colocated with NDB or VOR stations on a corresponding frequency allowing aircraft to get an accurate fix from a single ground station.

My understanding is that, for an aircraft to be suitable for IFR flight, the aircraft requires all VFR instruments (airspeed, altitude, compass, tach, oil pressure, oil or coolant temp, fuel gauge) plus a timepiece, gyroscopic direction indicator, Turn Coordinator or Turn/Slip Indicator, adjustable pressure altimeter, artificial horizon, and "two-way radio communication and navigation equipment suitable for the route to be flown", that last requirement being just wonderfully ambiguous regarding what you as a pilot may want or need from the above listed equipment.

The standard configuration for the 172 and Cherokee seems to be two OBIs, one with glide slope and one without, plus a single-channel ADF. This seems like a fairly economical gauge cluster for modern radionavigation, but the ADF seems old-fashioned in the face of the newer RMI that allows triangulation from an ADF and a VOR or two VORs more or less at a glance.

Obviously the very newest and most expensive aircraft have full glass cockpits, but for the rest of us, what displays are typically used? Do people tend to upgrade the ADI to an RMI, or is that the display that's considered redundant with NDBs on their way to retirement? How many people spring for the HSI? Do you keep the non-GS OBI if you have an HSI, or do you replace that with something else too? Is DME standard equipment, can't fly without it, or do pilots more often rely on multi-station triangulation for a position fix?


texts: What would happen if a plane lost half of its weight instantly?

texts:
During the Second World War the RAF had a 10,000 kg bomb, the "Grand Slam", which was dropped from a Lancaster bomber.

I assume that when this was dropped the plane would lurch upwards.

Is there any way of knowing just how big and violent a movement this would have been?

According to Wikipedia, a 'loaded Lancaster' weighed 25,000 kg. I'm not sure if this includes a standard bomb load (approx 6,350 kg) or not, but either way it seems that when the "Grand Slam" was dropped the aircraft would, in an instant, reduce to about half or two-thirds of its previous weight.

Is there any way to estimate how big an upward jump this would cause?


texts: What are the lateral limits of Class D airspace in the USA?

texts:
Class D airspace was normally 5sm (4.4nm) with extensions for approaches, when they are less than 2nm.  If any extension is over 2nm, then the extensions are normally Class E.  Many publications claim a 4nm Class D, but searching JO 7400.11A 1, there are many Class D airports with 4.2 or 4.4 or even greater lateral limits.

Some non-FAA publications claim that Class D is 4nm, but few Class D are in fact 4nm, most are larger, and many have extensions.  KFDK has a 5nm lateral limit for Class D, and Niagara Falls, KIAG has a 5nm lateral limit with an extension for approach.  Reading PA has a 4.2 and 4.8nm lateral limit depending on which side of the airport you are on.

My understanding that that Class D may be influenced by gradients for IFR operations, but also that Class D is frequently a customized airspace.

Furthermore, as an example, Class C airspace, when the radar is OTS (out of service) has the tower revert to Class D.  Will that be 4nm or 5sm?

Also, an operating federal control tower does not mean that an airport is Class D.  There are airports with towers which lack WX reporting, and are not Class D.  One which comes to mind in the past is LCQ, which is now KLCQ.

So where is the definitive set of rules which define Class D?

Where does a pilot obtain the lateral limits of Class D when Class C (or B) is not in place because of radar outage(s)?


texts: What caused the Belgian aircraft mechanic who stole an F-16 to crash?

texts:
This is the story, from the late 80s:

https://apnews.com/3b2ba1c5735b3817a3e7ae3562780e9b

Why did he crash? Why would anyone crash in this scenario?

I'd like to ideally hear from someone who is either an F-16 pilot or has been lucky enough to be able to try flying the F-16. Even if this has been ruled a suicide I'm still curious what beyond landing are the main challenges with flying the F-16 for someone untrained.

As someone who will never get that chance myself but likes flight simulators, I'm curious exactly where the big difference from the simulation to reality lies. I'm quite certain many others who fly flight simulators are also curious what the difference actually is. What stops someone that knows what all of the functions of the controls are, and is intimately familiar with the startup procedure for the engine of the F-16 (like a mechanic), from actually flying an F-16? Yes, landing, but what else? Do you need to remember to change some engine settings, fuel settings, after taking off, otherwise the engine stalls? Can you easily exceed EGT, or otherwise damage the engine, if you don't know what you're doing? Do you need to change some settings for the battery, internal power? I'm just guessing blindly here.

Forgive me for the hand waving like arguments I'm using, but, how hard can it be to keep an F-16 in level flight, if you are able to climb to 2,000 feet in the first place?

For the particular cited story above, it seems strange that the mechanic was able to take off and climb to 2,000 feet, and only then crashed. Does this point strongly to suicide?


texts: Can airlines choose whether or not to enable MCAS on their fleets, and if so, have US airlines chosen to do so?

texts: I've been told that, although all 737 Max aircraft are equipped with MCAS, the system can be deactivated by the individual airline.  I've also heard that US airlines never activated MCAS in their 737 Max aircraft.  Any truth to either?


texts: Why is it forbidden to wear glasses when leaving the plane during an emergency?

texts:
On my last flight with Iberia I noticed in the safety guidelines that you are not allowed to wear glasses during an emergency.

If I have to take off my glasses I would have serious problems seeing what is going on. So this makes no sense to me.

Why would I have to remove my glasses?


texts: Would the front rudder of the Wright brothers really have helped in recovering the glider from a stall?

texts:
I have found a paragraph in the 1904 British patent of the Wright brothers (see the citation below) and it seems, from what they explain, that the two inventors believed the front rudder could have recovered the plane from a stall in any situation.

The question is, why were they so sure that after a stall the plane would have started to fall nose down, would have accelerated and the front rudder would have been able again to control the pitch of the flying machine?

If the main wings (and also the front rudder) had stalled their glider/airplane could have started to fall sideways or tail first.

  "Contrary to the usual custom, we place the horizontal rudder in front
  of the main surfaces or “wings” at a negative angle, and use no
  horizontal tail at all. By this arrangement we obtain a forward
  surface which is almost free from pressure under ordinary conditions
  of flight, but which, even if not moved at all, becomes an efficient
  lifting surface whenever the speed of the machine is accidentally
  reduced very much below the normal, and thus largely counteracts that
  backward travel of the centre of pressure on the main surfaces or
  wings which has frequently been productive of serious injuries by
  causing the machine to turn downward and strike the ground head on."
   Wright brothers, “British Patent No. 6732, A.D. 1904 – Improvements in Aeronautical Machines”, Date of Application: 19th Mar., 1904, Accepted: 12th May, 1904.

  Wright glider


texts: What is the straight-and-level altitude record for a heavier-than-air winged/lifting-body aircraft?

texts:
There are many variants of the flight altitude record. The highest on the list is SpaceShipOne but rocketry isn't really "flight" in the sense of aerodynamic lift. What is the highest altitude for which:

The flight at a reasonably constant speed and altitude "straight and level". It is not in free-fall, so the "cabin" feels about 1g.

It is "heavier-than-air" and supported by lift rather than buoyancy. The engine thrust's vertical component is much less than the weight of the aircraft, so the wings or lifting body have to support the craft.

The speed is slow enough that centrifugal effects are negligible (i.e. it is not in orbit). This is the case below about 2.5 km/s (about mach 8).

The highest on the list that may qualify is in a Mikoyan-Gurevich MiG-25 at about 36000 meters. However, it is not clear if this was at the top of a parabolic arc initiated at a lower altitude. The highest (including unmanned) that surely fulfills the above requirements is the Helios HP01 at almost 30000 meters.
Helios HP01, although very light, is a very low-power craft that only uses propellers. One would think (sc)ramjet-powered craft would win due to the high speeds needed to generate lift in such extremely rarefied air. Is this the case?


texts: Why is jet fuel cheaper than piston fuel?

texts: Why is Jet-A cheaper than 100LL? Shouldn't it be the other way around?


texts: What's this part on the wing of BAE Systems Avro 146-RJ100?

texts:
It was always a question that what's this part on the wing of BAE Systems Avro 146-RJ100:

Is it kinda aerodynamic component?


texts:
Why don't airlines place some physical separator between passengers in the planes to prevent the spread of COVID-19?
A bit like the following, but adapted for cabins and viruses:

(image source)


texts: What is this F-18 Hornet "air intake" for?

texts: I think I read once that they served to cool the on-board computer systems, but I'm not sure.


texts: Can the airport name be omitted when contacting ATC if the frequency is not used by any other nearby airports?

texts: I was thinking of contacting Clearance/Ground/Tower/approach and omitting the airport name to shorten the transmission. If the freqs are not used by any other nearby airports, I figure there would be no confusion which airport I'm talking to.  Is there any other concerns that make this not a good idea?


texts: What are the differences between single and double annular combustion chambers?

texts: The combustion chamber of a jet engine may be can type or annular type. Annular type combustion chamber can be SAC (single annular combustion chamber) or DAC (double annular combustion chamber). What are the major changes between these  two types of combustion chamber? Is the CFM56-7B26 a SAC or DAC engine?


texts: What is this helicopter seen in the Falcon Crest TV series?

texts:
My next to last "Falcon Crest" related question for the database I'm programming: Does anyone recognize the make and model of this helicopter from episodes # 160 <7.05> (first screen capture) and # 163 <7.08> (second screen grab).
My guess is a Bell Jet Ranger, but I'm not sure.
Any hints are appreciated!  Thanks.


texts: How can I determine the relative bearing to an NDB using the G1000?

texts: For using an NDB, a pilot should know to MH+RB=MH. But I have never seen a relative bearing displayed in the G1000. Could you let me know where to see the relative bearing in the G1000?


texts: Could robots take over pilots' jobs and fly planes - if they can, then how?

texts: As technology is advancing, could robots take over pilots' jobs? If so, how might they accomplish this?


texts:
Living closer to a Sikorsky factory, I can attest that modern civilian (and military) helicopters are quite noisy. In any case, they are considerably louder than light aircraft, turboprops, and even some jetliners.

This has resulted in helicopters being banned from approach and landing in some jurisdictions.

It seems though, that the techniques for sound mitigation of helicopters have been known since at least the 1970s (The Quiet One) let alone the stealth helicopters used in the Bin Laden raid.

That is,  part of the solution appears to be to use more rotor blades while decreasing the speed of the rotors. There are also modifications to the tips of the rotor blades that while they may be classified, could be deduced and reverse engineered.

Why are helicopters so loud and why aren't contemporary helicopters quieter given what we know and how far we've come in materials sciences and aviation design?

Or is a question of economics (quieter == less economic) or politics (national security prevents the use of sound-mitigating technology) or something else?


texts: Why didn't Air India always fly DEL-SFO over the Pacific?

texts:
I read a 2016 article that said Air India broke a record for the longest flight (distance) by flying from New Delhi to San Francisco over the Pacific rather than a polar/Atlantic route. The total flight time was shorter because of the jet stream.

Why didn't they always do this?


texts: Will a portable ADS-B unit, like Stratus, meet the requirements for my aircraft to be ADS-B equipped by the 2020 mandate?

texts: There is a lot of confusion around what it means to have ADS-B.  What is the minimum equipment required to meet the mandate? Can I use a Stratus to meet that requirement?


texts: What is this thing on the engine of a Cessna 500 Citation I?

texts:
I've noticed something on the engine of this bizjet. Could somebody explain what that is?

Source (image modified to indicate location of fairing).


texts: Why shouldn't you inflate your life vest until you're outside the airplane?

texts: On commercial flights, in part of the pre-flight safety demonstration, you're told in the event of a crash, not to inflate your life vest until you're outside the airplane — why is this?


texts: What procedures are in place at London City Airport for emergencies after V1?

texts: Given the challenging operating environment at EGLC, what procedures are in place for emergencies after V1. Is it possible to return to the airport?


texts: Can an airplane fly with greater weight than lift and how?

texts: I just really don't understand how an airplane can fly with greater weight than lift.


texts: If flaps are used on takeoff, when should they be retracted?

texts:
If a pilot uses a notch of flaps on takeoff, when do they get retracted? At that time, what changes (i.e. climb rate, speed, pitch)?

NOTE: I have purposefully not specified the type of airplane.


texts: Are pilots over the age of 65 allowed to act as PIC for ferry flights between the UK and Canada?

texts:
I have been informed that I'm not allowed to act as PIC for a ferry flight to and from the UK for a Canadian commercially-registered transport aircraft that I currently fly in Canada for charter ops.

Does anybody have experience with this scenario and can provide input?

I have been told it is only permitted for privately-registered aircraft. However, My current understanding is that the regulations would apply internationally based on the national authority that the aircraft is registered under.


texts: Could an EFB-based pre-flight check be automated?

texts:
Since an electronic flight bag (EFB) is basically an iPad with the right app installed, is it possible that some sort of plane-tablet connection could be formed (either wireless or wired) to automate all of most of an EFB pre-flight check? Or does aviation regulation not allow this?

This is a purely hypothetical question since I don't think any EFB app so far supports this, let alone any plane.

Clarification: I'm talking about the preflight checks that ensure that everything in the cockpit is set up correctly for takeoff. I understand that an EFB is an electronic version of the 40 pounds of paper a pilot usually needs in the cockpit. Can this preflight check be done on the EFB? And can this be automated?


texts: How does fuel economy quantitatively depend on altitude for a jet?

texts:
We already have a few questions and answers about the qualitative effects of altitude on fuel economy:

How do I determine the best altitude to fly for fuel economy?
Why does fuel consumption decrease with increasing aircraft altitude?
What is the relation between an airplane's altitude and the drag it is experiencing?
Why do jet engines get better fuel efficiency at high altitudes? (contains formula for thermal efficiency)

I am interested in understanding how the changes in pressure and temperature at different altitudes affect the fuel economy of a turbofan powered aircraft quantitatively. In the end, I would like to make a plot of relative fuel economy vs. altitude that takes all of these effects into account, but I don't know how to quantitatively combine these effects.

Some notes:

By fuel economy I mean fuel required per distance traveled, not time.
I am not interested in absolute numbers for the fuel per distance, which would require specifying a particular aircraft. I am only interested in how the fuel per distance figure would relatively change with altitude, e.g. normalized to 1 at sea level.
I assume ISA (International Standard Atmosphere) profiles for pressure and altitude.
I assume the no wind case. Different winds at different altitudes will of course have an effect on the result, but it is easy to take this into account after the no wind case is understood.
Let's assume a typical climb profile for a short- to medium-haul jet airliner: 250/280/0.78

You can see that the TAS increases until reaching Mach 0.78, then decreases due to the lower temperatures causing a lower speed of sound and then remains constant above the tropopause. I am particularly interested in how the fuel economy will behave around these altitudes.


texts: Why are the modulation depths of the localiser and glideslope different?

texts: Why do we use a modulation depth of 20% (for 90Hz and 150Hz each) in the case of the localiser and 40% (for 90Hz and 150Hz each) in the case of the glideslope? Why not use 20% for both?


texts: How to program an FMC if the database is missing the arrival airport?

texts:
Let's say you are in a 737 flying to Geita, Tanzania, as you can see this little airport/airstrip has an IATA code, but not an assigned ICAO code. What should you enter into the FMC if I want to fly to that airport?

And in general, how to navigate to an airstrip that has only an IATA code?


texts: How to determine if flow transitions or separates from a Cp plot?

texts:
I came across this image:

My question is: given a general Cp plot, how does one tell from the shape of the curve if flow transitions or separates? Specifically, what features on the plot do I look out for that can tell me if flow transitions or separates (e.g. inflection points, plateaus, etc)

I know that a strong adverse pressure gradient causes separation which shows as a steep downward slope on the graph. What I don't know is where exactly on the graph transition or separation happens.


texts: Why is the A380 a double-decker rather than a longer airplane?

texts:
It seems like making the A380 a double-decker increases the cross-sectional area of the fuselage, thereby increasing drag on the airplane. Wouldn't it be more efficient to fit so many seats in a longer airplane rather than a wider airplane?

So, is the A380 a double-decker because there is a limit to how long an airplane can be, would it be impractical to make a longer airplane, am I wrong about the cross-sectional area/length trade off when it comes to drag, or is there some other reason?


texts: What does this METAR remark mean? 'RMK RWY 7 ATIS G LL'

texts:
I understand the long form:
"Remarks: runway 7 Automated Terminal Information Service (ATIS) G landline"

But what I don't understand is what runway 7 has to do with the ATIS information (this particular airport has one runway, RWY 7-25). What does the 'G' mean? What does the 'landline' mean?


texts: How high do they cut the grass on airports?

texts: I've read that they try to keep it short. But on other sites and documentaries, it is said that they have to keep it long so that the birds don't look for food. Which is correct: short or long?


texts: How does static port measures the static pressure?

texts:
I have always thought that there is a probe or sensor kind of thing inside the static port so that it "measures" the static pressure and compare to other pressure sources for airspeed, altitude, and VSI reading.

But my other pilot friend recently told me that the way static port works is because of the air actually flows in and out of it.

For example, when you climb, the ambient pressure decreases so the air will flow out of the static port until it reaches equilibrium, which causes the static pressure inside the casing of altimeter to decrease and the altimeter shows an increase in altitude.

Tried to find answers about how static port work online but did not find a satisfying explanation...

If anyone knows more on this topic please share your opinion.


texts: How does afterburner efficiency vary with thrust?

texts:
Afterburners are much less efficient than turbine engines at converting fuel into thrust, so AFAIK no jet will engage afterburner unless it is already at full throttle on the turbine.
But what if an afterburner were used at less than full throttle?  How, if at all, is the efficiency of an afterburner related to the thrust of the engine feeding it?


texts: How significant is the static buildup on the blades of the main rotor? And some questions related to this

texts: 1) Usually, a static charge is built on the helicopter when it flies through the air. If a person touches the helicopter before it touches the ground can that person get electrocuted because of the potential difference? 2) How significant is the static buildup on the blades of the main rotor? Are they grounded to the airframe of the helicopter? 3) What happens if a person jumps right into the helicopter while it's hovering, without completing the circuit with the ground? Like in the Matrix (1999), when Morpheus jumps off a building into a helicopter?


texts: What are these lines on the nose of a Boeing 737?

texts:
What are these lines on the radome?

You can also see them here:

What are they and what is their function?
Source: AviaFilms


texts: What is an approved weather source for flying an instrument approach into an airport with no working ATIS?

texts:
What can you use as viable weather information landing at an airport with ATIS inoperative due to the tower being closed after hours? Let's assume the approach secondary weather source is also unavailable but the ADS-B weather information is current.

My real question is: can you use ADS-B weather legally in this situation to shoot an approach if needed?


texts: Why is “L Fuel Low” illuminating on my Cessna that is full of gas?

texts:
I fly a fuel injected Cessna 172SP 200 hp. Tanks were just about full today and every 5 seconds or so in flight, I would get “L fuel low” and the left fuel indicator would drop to 0.
I’ve consulted with a few people and get differing answers. Some say it’s due to the blue dye in the tank? Some say bad sensor? Any thoughts?


texts: What flaps position should be used for taking off from a wet runway?

texts: If I have to take off in a C152 or C172 from a runway that's 800-900 meters (2600-3000ft) long and wet but not contaminated, what flap setting should I use to get the shortest ground roll?


texts: What are the design trade-offs between a pusher and a puller propeller?

texts:
Wich is the difference in having the propeller forward or back in an airplane.

I would like to know the technical differences like in a Piaggio 180 or in a normal Cessna.


texts: If cabin lights are dimmed during night landing so that your eyes will get used to the darkness, why do they let you use the reading lights?

texts:
Everytime the question of "why do they dim the lights during night landings" pops up, people say that it's to make passengers' eyes used to the darkness if an evacuation is needed (see: Why are the lights inside commercial airplanes turned off during take off and landing?)

However, on every commercial flight I've taken, the flight personnel always makes sure to mention that you can use the reading lights above you if you want, which are powerful enough to compromise your night vision (and that of people sitting next to you).

If the motivation is safety, why don't they disable these too? If anything, they should not be encouraging their use.


texts: Twin engine helicopters: is the throttle controlled separately for each engine or together?

texts: There is usually a twist throttle on the collective for a single engine helicopter. On twin engine helicopters, does the twist throttle control it for both engines, or just for one?


texts: What experimental techniques should one employ during cruise flight to determine correct airspeed to fly for max range in a headwind or tailwind?

texts:
Theory demonstrates that one ought to increase speed in an headwind, and decrease speed in a tailwind to achieve maximum range.  A lengthy discussion on the theoretical solution was answered, though not clearly, here.  It is unlikely that a pilot will have the Thrust Required chart on which to draw a tangent line through the x-axis intercept at the given wind speed.

What simple techniques should the pilot employ to determine the best speed to fly given specific environmental conditions (fixed headwind or tailwind)?


texts: Why did the propellers not fail to the feathered position in the Atlantic Southeast Airlines Flight 2311 Crash?

texts:
In the ASA Flight 2311 crash the failure of a quill resulted in the loss of propeller pitch control.  The propellers ended up with a pitch angle of 3 degrees which caused reduced thrust and increased drag resulting in severe asymmetrical thrust situation.  The airplane was uncontrollable in this configuration and crashed. The propeller manufacturer, Hamilton Standard, had tested the propellers in a laboratory and had shown that the propellers will feather with a loss of pitch control.  However, a flight test orchestrated by the NTSB had shown that due to the "aerodynamic forces of flight" the propellers did not feather as designed.

My question is what exactly caused the propellers to not feather in flight when the propellers successfully feathered in the laboratory?  I am looking for a more detailed answer than "aerodynamic forces of flight".


texts: What is the average temperature in the luggage hold of a passenger plane?

texts:
I am asking this seemingly odd question, as we'll have to transport some medicine in our luggage and it's supposed to be stored at temperatures between -8C and +2C. I'm not sure, if airport security will allow this to pass if this is in a cooling box as hand-luggage, although, in my opinion there shouldn't be a problem, as the ampules are 4 x 1 ml and I have a prescription (however, the cooling box will probably be treated as partially liquid containing).

Your advice will be much appreciated!


texts: Now, we have seen the UFOs by US Navy's onboard cameras, they are so fast and they do change their directions very quickly. How do they do so almost breaking the laws of physics?


texts: What are ways to reduce drag and noise generated by the landing gear?

texts:
Apart from using fairings, what ways are there, or have been studied, but not necessarily implemented in reducing drag and noise produced by the landing gear, mainly for commercial aircraft with retractable landing gear, but would also like to know about smaller aircraft, perhaps with non-retractable landing gear.

Is there a study or a design that has been done on landing gear to reduce drag and/or noise produced by the landing gear?


texts: Is there a relationship between 2D airfoil aerodynamic results and a revolution body from that airfoil?

texts:
The airfoil would be symmetric and the axis of revolution would be its chord line.

Edit1: To clarify the question, suppose we have a NACA 0010. Then, using for example XFoil, I'm able to get, for example, Cd(AoA). Now, I take the airfoil, and I create a body of revolution, with the axis of revolution being the chord line of the airfoil, with the resulting body being like a teardrop. I want to know if there is a way to correlate my 2D Cd(AoA) to the 3D Cd(AoA) of the body I created, so I can predict some of its aerodynamics (with some degree of accuracy) without having to run 3D CFD analysis on it.


texts: What will the impact to GA be if DTC DUAT goes away?

texts:
Data Transformation Corporation issued the press release below.

  FOR IMMEDIATE RELEASE

  DTC DUAT Contract Extension

  May 21, 2015 — Data Transformation Corporation, DTC DUAT which
  supplies the DUAT Service for the FAA for the past 25 years, has
  announced that it has been granted a 60 day extension by the FAA to
  continue to provide the FAA DUAT service. DTC DUAT has always been
  committed to making the DUAT Service better for General Aviation
  pilots by adding new features and services making it easier to get
  weather briefings and file flight plans. DTC would like to inform all
  of its users and third party vendors that we are fully operational and
  plan to continue operations during and after the 60 day period. DTC
  DUAT is pursuing alternative avenues to provide the DUAT Service
  capabilities to its users following the 60 day extension period.

  For more information on this topic or anything about DUAT, please
  contact our marketing manager, Doug Priestley, at (800) FAA-DUAT
  (322-3828) or by email at
  marketing@dtcduat.com.

If the alternative avenues do not produce the desired results and DTC DUAT operations cease, what will be the real-world, day-to-day effects on general aviation?


texts: What is the relation between hinge moment at the control surface and servo torque?

texts:
I am trying to estimate the required servo torque for my design using hinge moment at the elevator.

XFOIL results were as follows-

I am getting a Hinge moment of about 0.06-0.08 Nm. for the given deflection.
How can I relate this to the servo torque I require? Will they be equal?


texts: How does the Blackbird SR-71 pressurize the cockpit at Mach 3?

texts: I'd assume the Blackbird's engine that converted into a ramjet once at supersonic speed had no moving parts at ramjet phase. If the engines were off, how then did it pressurize the cockpit at cruise altitude to ensure pilot safety and that he/she did not pass out from lack of oxygen?


texts: How long are modern variants of the F-16 expected to be in production?

texts:
The F-16 seems to keep receiving updates and new aircraft appear to still be in production, e.g. the F-16I and F-16Q. It seems there are also several upgrades being developed and installed, such as radar (AESA) and radar detection warning systems.

Has any authority on the subject attempted to estimate how long the F-16 is expected to be in production? Is there any estimated limit on for how long a budget fourth generation airframe can be used as the basis of a modern combat aircraft?

I'm not looking for speculation from StackExchange users but rather a reference to a statement made by one or several external authority -- to avoid making this question opinion based. Some sensible original reasoning is only a bonus as far as I'm concerned.

I can only imagine myself that countries that keep buying F-16s do so for budget reasons -- however, there must also be some real value in buying F-16s in 2019, since these are after all large sums of money even if it is bleak in comparison to e.g. F-35s or F-22s.


texts: Was the safe landing of Southwest flight 1380 extraordinary or expected?

texts:
I've been reading with great interest and concern about the recent Southwest flight that resulted in the first fatality in that airline's history.

There's one question I haven't seen answered, though: Was the plane really in serious danger of crashing?

I have long understood that two-engine commercial airliners are designed to be flown safely with one engine. However, are they designed to be flown safely with only one engine as well as a depressurized cabin and broken window? Do these three things in combination make a plane significantly harder to fly or land than just an engine failure?

The passengers aboard this plane had plenty of reason to be terrified, what with oxygen masks dropping from the ceiling and a woman nearly being sucked out of the plane (and ultimately dying from the head trauma she suffered), but the accounts I've read seem to suggest that many thought crashing was the most likely outcome and were preparing for their death.

I don't want to take anything away from the pilot, Tammie Jo Shults, who clearly performed superbly under stress and exhibited the highest level of professionalism, but was her safe landing anything other than the expected outcome?


texts: What's the functional difference between PAPI and VASI?

texts: PAPI and VASI seem to be very similar in the the information they provide - i.e. are you on the glide slope or off it. Is there a functional difference between the two? If there is a difference, and one is superior to the other, is there a construction cost savings where an airport might chose one over the other?


texts: How much can a plane benefit from another planes wake?

texts:
Could a smaller plane fly in a V formation behind a much larger plane to reduce fuel consumption significantly more than a plane its own size? At what point does flying in a larger planes wake become to turbulent or increased fuel efficiency stops?

Related: How do planes benefit from flying in formation?


texts: What is the ILS glide slope deviation on a 4 degree VOR check error?

texts:
On a US IFR flight, it is required to do a VOR check every 30 days and the error tolerance is 4 degree except for airborne check.

Suppose I have 4 degree error on my VOR check. When I fly an ILS and right on the indicated glide slope, what is the maximum degree of deviation from the actual glide slope? (range of my actual glide slope)


texts: Is it possible to convert a passenger A380 to carry cargo?

texts:
I heard an expert say that one of the A380's weaknesses is that it only comes in a passenger version, not a cargo one like the B747 does. The cargo version of the B747 makes its market wider. One more weakness of very large jumbo jets (A380 and B747) is that, nowadays, most flights fly directly to the destination (point-to-point), not hub-to-hub as in the 1970s. The point-to-point model causes airlines to make more frequent flights with smaller aircraft. In my country, even small airports are now international airports. Two neighbouring cities in neighbouring countries have small propeller aircraft flying directly between them, without having to go through the main airport in one country's capital city. This makes it very clear that very large jumbo jets are no longer required for passenger service.

On the other hand, the demand for air cargo has never been greater. Trade over the globe has to be quicker. This means that large jumbo jets are needed in cargo service, and - to allow easy centralization of cargo-handling equipment and personnel - it's generally preferable for these freighters to operate to and from the largest, most central airports in a country.

The question is, is it possible to convert an A380 for cargo service when there is no longer a market for the passenger version?


texts: What is the top speed of the twin seat Hawker Hunter?

texts:
Recently I learnt that the Hawker Hunter had a side-by-side twin seat trainer version. This is unusual, since more often the tandem configuration is used. I'm sure the engineers had a good reason to choose this solution, but it got me wondering: how much is the top speed impacted by the resulting increase in frontal area?

From what I've found online, the specs are the same for both trainer and single-seat versions but that doesn't seem right; if nothing else, the empty weight should be different. Is there a former Hawker Hunter pilot here who trained on the twin seater and can tell us the truth?


texts: Can you escape an aircraft through the lavatory?

texts:
In his book "Catch me if you Can", Frank Abagnale claims he evaded arrest by removing a panel in the lavatory of a VC10, climbing through it and hence escaping out of the (taxiing) aircraft through a hatch.

Could this actually have been done?

Plagiarism disclaimer: I found this question on another forum but didn't see a suitable answer there.


texts: What was the first commercial scheduled flight to Australia from another continent (except Asia)?

texts:
Australia has been a very isolated country, ships being the only possibility to get there from another continent if someone was not too much in a hurry. Aviation did add a new and radically different possibility.

Source

When and how did occur the first commercial scheduled non-stop flight to mainland Australia (country) from mainland Americas, Europe, Africa or Antarctica? I'm excluding overseas islands and Asia which are easier challenges.


texts: Upgrading a Sport license to a Private license - is a new student license necessary to solo non-LSA aircraft?

texts:
I hold a sport pilot certificate and a valid third class medical. I'm pursuing a private pilot certificate and receiving training in C172's and C182's, though I also have access to a C162. I was wondering if I can be signed off to solo in the non-LSA aircraft without going through the process of obtaining a student pilot certificate, and just getting the logbook endorsement as follows:

  I certify that (First name, MI, Last name) has received the required presolo training in a (make and model aircraft). I have determined he/she has demonstrated the proficiency of FAR 61.87(d) and is proficient to make solo flights in (make and model aircraft).
  4/25/14 J. J. Jones 987654321CFI Exp. 12/31/05

I have several solo missions that could benefit from additional power and useful load provided by the larger aircraft, but with the new student pilot certification process, I'm wondering if it's worth the hassle.


texts: In which countries a medically unfit US pilot can fly?

texts:
For example can one get another license in a foreign country?

Which countries allow that?


texts: Which radio frequency is used during a flight interception?

texts: What kind of communication do the intercepting and intercepted aircraft use? Is it the usual air-to-air frequency or the international emergency frequency?


texts: How do airlines without assigned seating verify cargo balance?

texts:
How to approximate the mass of passengers is well explained, but balance of the aircraft is concerned more with where they sit. Other answers have hinted that assigned seating locations are one method for calculating loadsheet balance, but this is not always an option.

Certain passenger airlines (such as Southwest) do not assign seats, allowing passengers to select whatever seat they like during boarding. Since passengers must be accounted for in load balance calculations, how do these airlines know how passenger mass is distributed? Are there strategies besides knowing exact locations to determine whether cargo balance will be within the envelope? Do they simply have flight attendants record where passengers are seated?


texts: What is this extension at the tip of the Supermarine Southampton's wing?

texts:
Looking at this Wikipedia image of the Supermarine Southampton flying boat, I noticed what at first looked like a small wheel. But then I thought it couldn't be, as a wheel would be pointless in a flying boat (not to mention, it appears to be only under the right wing).

Any idea what it could be?


texts: How does the engine produce aerodynamic lift at high angle of attack?

texts:
This answer asserts that "at high angle of attack the engine is producing aerodynamic lift". In the context of that answer, we are concerned about the increased torque that raises the nose of the aeroplane with respect to the center of gravity, so we should narrow down our interpretation of the otherwise vague word "lift" as the force component that is perpendicular to the wing or fuselage of an aeroplane. We define the angle of attack as the angle between the fuselage and the incoming airflow direction at infinity (shorthand word for "reasonably far away"). It is very different from the angle of the fuselage makes with the horizontal at high speed while very close to the latter at very low speed. It puzzles me in two ways.

It claims the engine itself produces fuselage-perpendicular force in addition to the thrust parallel to the fuselage and wing, despite the thrust of the engine is directed parallel to the fuselage and thus the wing. How is that perpendicular force produced?
It claims that fuselage-perpendicular force thus produced is dependent on the angle of attack. How does that work?

I would like to see a technical elucidation of this claim or some references supporting or refuting it, best if they come with mathematical derivation.

Edit:

Some answers below observe that when the plane moves, without engine turned on, against the airflow, part of the airflow curves downwards to conclude that a net force perpendicular to the fuselage is exerted. It is not that simple as looking at part of the flow stream, since part of the flow stream goes upwards above the separating point. The net force is the integration of all the pressure on the whole surface, and the pressure on the opposite side of the object presses in the opposite direction. In fact, in a potential flow, the D'Alembert's paradox  shows that the net pressure is exactly zero. Of course, real airflow is not potential flow, but this refutes the overly simple rationale of using downward airflow to derive the fuselage-perpendicular force.

However, when the engine is turned on, especially at high power. The situation may be different so long as the airflow is consistently flowing in the downward direction long after exiting the engine. The momentum of the airflow through the engine may overwhelm other parts of the airflow. But the argument must be more sophisticated than just the downward direction of the airflow.


texts: Identify a balloon accident in the 90s or 2000s

texts:
I recall hearing about a balloon accident on a news programme on TV in the 90s or 2000s. From memory it was some sort of record attempt, and the last telemetry from the flight indicated that the gondola was in free-fall.

I seem to recall a crew of at least two people. I think it happened over the sea, certainly far from where anyone could observe it, hence the need to rely on radio for communication with the crew and telemetry.

At the time of the report it wasn't know exactly what happened or the fate of the crew, but the free-fall telemetry made it sound pretty bad.

Can anyone identify this accident?


texts: Is it okay to take off with weight more than the POH max gross weight?

texts:
I wonder if I could take off with weight more than the gross weight stated in the POH of my aircraft as long as I take off with a higher speed?

I think I have done it once by mistake.


texts: What's the difference between a Terminal Control Area and a Control Zone?

texts:
From what I've understood, in Canada a Terminal Control Area (TCA) is established at airports with a high volume of traffic to provide IFR control service to arriving, departing and en route aircraft.

A Control Zone is designed around aerodromes to keep IFR aircraft within controlled airspace.

Why do we have both? Both provide ATC services, so why do we require a Control Zone within a TCA? Is there a specific reason that the TCA cannot be lowered below 700 AGL?

See this reference material in "From The Ground Up" (I've tried to attach it but it didn't work).


texts: What are flight envelope limits of the Stearman Model 75?

texts:
Recent monopropeller aerobatic aircraft such as the Zivko Edge 540 have impressive flight envelops limits (up to ±12G, $V_{NE}$ (230 kn) up to 4 times its stall speed ($V_s = 51kn$), low stall speed, ...). I would like to know how it compares with an old biplane with an open cockpit commonly used in air shows such as the Boeing-Stearman Model 75.

What are the flight envelops limits of the Stearman 75? I'm particularly interested in the following numbers:

load factor limits (both negative and positive G)
Speeds limits (both $V_{NE}$ (never exceeded speed) and $V_s$ (stall speed))


texts: Do you ever get to practice ejecting out of a plane as a fighter pilot?

texts:
The military throws away a lot of equipment simply because it doesn't hold up to current standards. So I was wondering the following.

As a fighter pilot, would you ever get a practice run ejecting out of a plane, or is it just kind of one of those things you read about and hope you never have to do it? What is it like ejecting out of a plane at 500 knots? 1000?


texts: What does " X miles in trail, runway 25R cleared to land" mean?

texts:
I was listening to the LiveATC Phoenix North Tower feed as he was clearing aircraft to land. He said something like "Southwest fifteen sixty five, Phoenix Tower, (aircraft type), X miles in trail, runway 25R, cleared to land".

What does the "(aircraft type) X miles in trail" portion mean?

Is the controller pointing out the aircraft behind the aircraft that is being given the landing clearance? If yes, why would the aircraft in front care?


texts: Why are some seemingly major waypoints nowhere to be found on sectionals (including enroutes)?

texts:
I'm looking at the BNTLY.CAVLR3 arrival at KIAD:

Almost none of the waypoints (BNTLY, CAVLR, COINZ, etc.) are on a single sectional or chart, enroute or otherwise. Considering this is such a major route into such a major airport, why would these waypoints not appear? How would one ever hope of finding their location?


texts: What makes flight recorders harder to find than tagged sharks?

texts: It really bothers me that we can't find planes that weigh tons with black boxes (AFAIK) technology that's almost obsolete, on the other hand shark tags (AFAIK) work great for long time and we can monitor shark movement, depth, temperature, etc., all the time. So, why?


texts: Consequences of stalling while sideslipping in a glider?

texts:
In a glider, sometimes it's useful to do a side slip with crossed controls. However, when that happens, the pitot tube angle is out of line and the ASI goes to zero, therefore losing any indication of the current airspeed until the sideslip is interrupted.

During this maneuver, what would happen if I were not to keep proper control of the attitude, and thus airspeed, and were to stall the wings? would the glider spin, or would the unusual attitude prevent it?

Edit: The duplicate question does not necessarily responds as it seems to address powered airplanes, where other factors may be in play. My question targets specifically gliders.


texts: Why does the attitude indicator gyro not precess the same way that a directional gyro does?

texts: The directional gyro needs to be realigned every so often, but the attitude indicator does not, and I have a hard time finding why.


texts: What weather products do you use to determine whether or not a flight is safe?

texts: There are many weather products available on AviationWeather.gov and many other sites. What do you use for preflight planning?


texts: I don't understand how it works, can someone provide me with details?


texts: To which airspace does the border of two adjacent airspaces belong to?

texts:
Consider two adjacent airspaces of different categories. For example, airspace G is up to 2500' and above this is an airspace D. The border is at 2500'. Which airspace are you in if flying at exactly 2500'?

I recall a definition by ICAO that said that the border between such airspaces belongs to the less restrictive one, but I can't find that document.


texts: What equations and constants did they use to build the E6B flight computer?

texts:
E6B Flight computer:

During my practice test, I tried to use the wikipedia provided equations to calculate Density Altitude and ended up with different results than the E6B.  In this case, it looks like the E6B uses something like 130FT/DegC as opposed to posted 118.8 indicated on Wikipedia.
Is there a source for the actual equations and constant values they used for the values on the E6B?


texts: What type of visa is required to be allowed to earn a PPL in the US?

texts:
What are the visa types (H1b, L1b, H4, L2, J1, etc) accepted by TSA to learn flying for recreational purposes?

UPDATE 1

I found some further information from National association of flight instructors, According to them; Person on work visa can follow Part 61 course and get the PPL.

UPDATE 2

I have received the permission from the TSA to flow the Category 3 flight training. It took around 1 & 1/2 weeks to process and it will cost around 130 for the application and 99 for fingerprint process.

Based on this process, I understood that L1 Or L2 Or H1 Or H4 holders are eligible with the right set of document and no criminal record.


texts: How much earlier/later is sunrise/sunset at 40,000 feet?

texts:
If I'm over New York City, and sunrise is 6am, I will see the sunrise earlier when I'm at 40,000 feet on the plane.
I think that latitude plays a role here, but using NYC as an example, how much earlier/later (later for sunset, as I will see the sun for a longer period at that height) are these events on a plane than on the ground?


texts:
When a composite structure is hit, the impact causes shockwaves which travel through the structure, and cause delamination. Delamination reduces the strength of the composite structure and may cause the structure to break at a fraction of the load it would have carried before the impact.

Delamination and its ill-effects can be reduced, for instance by adding metal at strategic points of the aircraft. But once delamination occurs, how can it be detected? What measure (if any) have been implemented to detect delamination on aircraft?


texts: What are the differences between the proportional flow control FCU and pressure control FCU?

texts: what are the basic differences between the proportional flow control FCU and pressure control FCU? ( FCU : fuel control unit )


texts: Passenger hypoxia in a small plane at 11,000 feet: what is the pilot's responsibility?

texts:
An acquaintance of mine visiting western U.S. was recently a guest passenger in a small plane flying from Santa Fe, New Mexico to Colorado reaching an altitude of 11,000 feet. She related that she started experiencing hypoxia and there wasn't any supplemental oxygen available. Apparently they couldn't reduce altitude (mountains). She said that since then she has had trouble breathing, has gone for medical tests, etc.

I didn't want to be "that guy", so I didn't ask, but it occurred to me to wonder if the pilot was irresponsible in not having supplemental oxygen available. Apparently the pilot and his other passenger were from the area and acclimated to the altitude.

Since one can't just "ask" someone if they will be OK at that altitude, should the plane (pilot) have had oxygen available? In other words, is this an area of pilot responsibility?


texts: I am currently reading a book at the moment, and I got to a point were a UAV was hacked, piloted, released its pay load and crashed, could this ever happen in real life?


texts: How to trim in level flight when speed increases?

texts:
What is required to happen to control surfaces and trim tabs to remain trimmed in straight and level flight, as speed increases? (for a GA propelled aircraft)

My manual tells me that the elevator should be further deflected downwards, and its trim tab further upwards.

I understand the reason for the trim to deflect in the opposite direction of the elevator (to help maintain it in that position), but don't get it for the elevator.


texts: Which engine type requires the shortest take-off run: a turboprop or a turbofan?

texts: If two fixed-wing aircraft almost identical except for the engines, one turbofan and one turboprop, which one would need less runway to take off?


texts: What would happen if flaps are extended beyond 40 degrees?

texts:
The angle of flaps is limited to a specific value. It's around 30° to 40° on most aircraft what I've seen.

Source

But what happens when they get extended even further? 50°, 80°, 90°, ...
Let's also say they don't break due to high load on them. I just want to know it theoretically.
What will happen to the plane?

Will drag be increased?
At which point will the aircraft loose it's lift due to the extreme deformation of the wing?
What about the slats?
Are there any aircraft that use a higher than usual angle of flaps?


texts: How do I include a STAR in an ICAO flight plan?

texts:
Would it be in accordance with ICAO norms to include a STAR identification right after the airway name in the field 15 of the flight plan? Or should the connecting point between the airway and the STAR be included before the STAR?

Example without CP:

  R460 LKN R594 JAL5E

Example with CP:

  R460 LKN R594 JAL JAL5E


texts: What light signals or visual markings indicate that turns should be made to the right at class G airports?

texts:
FAR 91.126 states:

§91.126 Operating on or in the vicinity of an airport in Class G airspace.
(a) General. Unless otherwise authorized or required, each person operating an aircraft on or in the vicinity of an airport in a Class G airspace area must comply with the requirements of this section.
(b) Direction of turns. When approaching to land at an airport without an operating control tower in Class G airspace—
(1) Each pilot of an airplane must make all turns of that airplane to the left unless the airport displays approved light signals or visual markings indicating that turns should be made to the right, in which case the pilot must make all turns to the right; and
[...]

Are there examples of "approved light signals or visual markings indicating that turns should be made to the right"?


texts: Will EASA approve single engine IFR commercial operations any time soon? Will this be a big impact on the industry?

texts: I saw that discussions were going on for EASA to approve single engine turbine airplanes for IFR commercial operations. Anybody knows the current status? Where can I find it? Is it going ever to happen? Another question is how big impact this is going to make? Are SAT much more efficient and cheaper to run than multi engine aircraft?


texts: How far along was JFK Jr. in his instrument training?

texts:
I read up a little more about the infamous and tragic incident. JFK Jr. had over 300 hours logged, and about 36 in the Saratoga, half of which was solo. It's not like he was a newly minted VFR pilot and supposedly his CFI thought he was an "excellent" pilot.
However, there was very little information on how far along he was in his instrument training. Did he just get the minimum requisite time under the hood? Did he begin pursuing IR training?


texts: Why is tethered hover testing performed on helicopters?

texts: The KGUC website notes that they have a tether for helicopter testing. From what I can tell this testing has something to do with hot and high conditions, but I don't know what the purpose is of testing with a tether. Here is a video of testing being performed. What is tether testing for?


texts: Can anyone identify what/where this photo is of?

texts:
This is a photo by the Real Photograph Co. (Liverpool) No.684.
I think it may be a crashed WW1 Biplane (lots of the photos with it were WW1 biplanes).


texts: How are evacuation tests made as realistic as possible?

texts:
I've seen the video of the A380 evacuation test and similar ones.

While the fast evacuation is impressive, a criticism often heard (and read in the comments on YouTube) is that these people were prepared and (roughly) knew what was about to happen. Also, people in the back of the queue were not in fear of their lives, so they just waited on their turn.
No one tried to go against the stream to look for loved ones seated in different rows, no one tried to get at their personal belongings to try and take those with them.

What measures are taken to make evacuations tests as realistic as possible?

I've heard that incentives are offered to passengers to get out as fast as possible, for instance $100 for the first X passengers to get out. Is that true? If not, anything else?
I of course appreciate the conflicting interests that while ideally the test should be as realistic as possible, the test passengers can't be endangered.


texts:
Can anyone explain what a rhumb line is and how it is different from the great circle route?

This what the internet says:

  Rhumb lines are tracks with a constant track direction between two points on a sphere and therefore must be a longer distance than a great circle track.

From pprune.org

What does it mean to have a constant track direction?


texts: Are you required to have constant view of the runway when circling?

texts: When you're circling, it has been said that you are required to keep view of the runway at all times below the MDA. However, sometimes this can be impossible due to issues with visibility, such as being banked to turn around for final, or because a flock of birds are circling between the airport and your aircraft. Are you required to execute the missed approach if this occurs or not?


texts: When was V1 speed first introduced? Was it the result of a particular accident or series of accidents?


texts:
The Sikorsky UH-60 (S-70) has a tail rotor that is canted 20 degrees upwards. Why is that?

Picture source


texts: Why is the Airbus Beluga XL based upon the A330, and not upon the A350 or A380?

texts:
Airbus is developing the successor of the Beluga, called Beluga XL.

The original one was based on a standard A300, while the new model will be based on the A330.

Why is the new model based on a quite old design like the A330, and not the more modern A350 (which could generally be more efficient and have more modern avionics)?
In addition, I saw that Boeing built an equivalent aircraft, the Dreamlifter, based upon its biggest model, the 747, so... obvious question: why doesn't Airbus base the Beluga XL off of its giant, the already-tested A380?  This could offer a much better payload capacity, and, maybe, even the ability to carry fuselage sections of future A380s (which, currently, must be transported by trucks due to their size).


texts: How does air conditioning work on a commercial airliner?

texts: I know a lot about airplanes, but I've always wondered the vents deal with air pressure in the sky


texts: How to fly LOC approach when IAF is a specific DME from LOC, but LOC has no DME?

texts:
I was looking at this approach plate and noticed that SNOWL is an initial approach fix, and that it's charted to be 6.4 NM from the localizer I-IWA.

The only problem with starting my approach from the northwest and crossing over SNOWL is that the localizer does not have DME.

First Question:

How can I fly this approach assuming that I'm coming in from the northwest and want to start from the initial approach fix SNOWL?

Second Question:

If SNOWL is 6.4 NM from, why does the profile view show that it's 5.8 (1.9 + 3.9) NM away from the localizer?


texts: Why do passenger jet manufacturers design their planes with stall prevention systems?

texts: I understand why passenger jets use software that overrides pilot inputs that might cause the jet to exceed the flight envelope.  But why do passenger jet manufacturers design their planes with stall prevention systems?  Shouldn't professional pilots be well aware that a stall is possible when the airspeed is too low, or the angle of attack is too high?


texts:
What is "Defense Area" on a VFR Sectional Chart? The words "DEFENSE AREA" (in all caps) appear all along the US/Mexico border in blue. It's the biggest text on the chart. Interestingly enough, the same words don't seem to be along the US/Canada border.
Someone on airliners.net said this:

You're correct, there is a difference between a ADIZ and a Defense Area. A defense area is an area established on non-federal lands located within the United States, its possessions or territories, for the purpose of safeguarding classified defense information or protecting government equipment and/or material.
The establishment of a national defense area temporarily places such non-federal lands under the effective control of the Department of Defense and results only from an emergency event.
I am surprised that it is charted though, unless of course the government is getting ready for the flood of illegals coming to California to get drivers licenses and registering to vote.

That makes it sound like a ground thing, not an air thing. Then there's this, in the CFR 99.3:

Unless designated as an ADIZ, a Defense Area is any airspace of the United States in which the control of aircraft is required for reasons of national security.

And in the CFR 99.49:

All airspace of the United States is designated as Defense Area except that airspace already designated as Air Defense Identification Zone.

And in the AIM:

Defense Area means any airspace of the contiguous U.S. that is not an ADIZ in which the control of aircraft is required for reasons of national security.

So, what exactly is this Defense Area on my Sectional Chart and do I need to worry about it or think about it as I fly?
From the CFR 99.3 quote, what does this mean?

in which the control of aircraft is required for reasons of national security


texts: Are all IFR flights assigned squawk codes in US controlled airspace?

texts: In the US, all IFR aircraft need a clearance to be in class A, B, C, D, and E airspace. Does this mean that all aircraft with clearances need to be assigned squawk codes by ATC when they enter?


texts: Why are there so many ADS-B ground towers in western Colorado?

texts:
I was reading up on Appaero's new ADS-B OUT transponder and clicked over to the Stratus coverage page for some reason. Then I glanced at the map, and noticed something interesting:

Western Colorado is, well, ADS-B tower central. What gives? Chicago and the northeast are close, but not nearly as dense.


texts: Why don't flight attendants get tired when passengers can, despite sleeping?

texts:
This Reddit thread refers to "stressors of flight" (many of these stressors are also present in automobiles), sudden altitude adjustment, lower cabin humidity., proximity to strangers.

Yet flight attendants face these stressors too, but they don't appear tired?

I don't think sleep answers my question. I know that on long flights, they are allowed to sleep in crew rest compartments, while passengers sleep too but still can remain tired.


texts: Why does drag coefficient decrease with Mach number in the supersonic regime?

texts:
I'm trying to understand why the drag coefficient decreases in the supersonic regime with Mach number. While it is easy show this using supersonic, potential flow theory, I'm looking for a more physical explanation.
My initial thought is, as freestream Mach number increases, the shocks should become stronger (even though they are more oblique, the normal component to the shock is still larger). Where is this train of thought going wrong?


texts: Do a turboprop’s compressor and turbine rotors windmill when the engine is shut down and feathered?

texts:
If a jet engine is shut down in flight, it continues to turn due to the aircraft’s forward motion forcing air through the engine, causing it to “windmill” in the airflow.

Is this also true for turboprops?  When a turboprop engine is shut down and its propeller feathered, do its compressor and turbine rotors keep windmilling in the aircraft’s slipstream, or do turboprops have some way of closing off their engine intakes to prevent this when the engine is shut down?


texts: Can a lifting body work at supersonic speeds?

texts: Can lifting bodies be made for supersonic flight, say up to Mach 3? What would they look like? How would they differ from lifting bodies for normal subsonic flight?


texts: Why are the VHF and UHF airbands directly adjacent to frequency bands used by vital radionavigation aids?

texts:
Of the three main frequency ranges used by aircraft for radio communications (HF, VHF, and UHF), two (VHF and UHF) have their aircraft-radio-communications frequencies clumped together into a contiguous (or almost contiguous) airband1 (117.975-137 MHz for VHF, and 225-328.6 MHz and 335.4-399.9 MHz for UHF2).

Interestingly, and somewhat worryingly, each of the VHF and UHF airbands is immediately adjacent to a band of frequencies used by vital radionavigation aids:

The VHF airband (117.975-137 MHz) lies immediately above the 108-117.975-MHz band used by VOR and localiser transmissions.3
The two UHF airbands (225-328.6 MHz and 335.4-399.9 MHz) are separated by the glideslope-transmitter band (328.6-335.4 MHz).

This raises the possibility that a malfunctioning (or even just poorly-tuned) VHF radio could cause interference for VOR or localiser signals if it went even slightly out-of-band, or (much worse) that a mistuned or malfunctioning UHF radio could end up stepping on somebody’s glideslope.

Given the navaid-interference potential thereby caused by this adjacency of radiocommunications and radionavigation bands, why do both the VHF and UHF airbands directly border frequency bands used by vital navaids, and how are out-of-band VHF and UHF radio transmissions prevented from thereby causing interference with these navaids?

1: The HF frequencies used for aeronautical radio communications, in contrast, are split into multiple discrete bands spread out throughout the entire HF range.  This is because the main attraction of HF is its ability to transmit and receive signals far beyond line-of-sight range (potentially even enabling an aircraft to talk to someone at the aircraft’s antipode, on the opposite side of the planet); which HF frequencies work best for this depends on the current state of the earth’s ionosphere, which varies considerably due to things such as solar activity, variations in the Earth’s magnetic field, recent high-altitude nuclear explosions, supernovae, witchcraft, etc., so the aeronautical HF bands are scattered throughout all HF in order to ensure that there should be at least one useable band no matter what (the frequency bands used for shortwave radio broadcasting are likewise scattered throughout most of the HF range [although, surprisingly, not the lower end], for the same reason).  In any case, the HF range has no radionavigation bands of any sort whatsoever, making it not a concern for the purposes of this question.

2: Which, if you want to be pedantic, places a good portion of the UHF airband in what is actually the top end of the VHF range.

3: And the 108-117.975-MHz radionavigation band is, in turn, immediately underlain by the FM broadcast band (88-108 MHz), but, as there are fewer FM radio stations than there are VHF-radio-equipped aircraft, and they are bigger and easier to spank if they get out-of-band, this is less of a concern from the interference-with-navaids perspective.


texts: Who must approve a globally distributed satellite to ground laser communication system?

texts:
Laser Light Communications (US) plan for several dozen optical high speed data links between satellites and ground is described in Aviation Week's article Big Gains On Horizon For Laser Communications Suppliers and Lightwave's online website: Laser Light to leverage free-space optics in space for Optical Satellite as a Service.

  All Optical Hybrid Global Network (or HALO, as laser Light calls it)

The plan is to use lasers to establish optical links between satellites in Earth orbit (MEO) and between them and a network of ground stations.

  According to the company's website, Laser Light will leverage 8 to 12 satellites in medium Earth orbit to create a network that will offer an initial service capacity of 7.2 Tbps. The satellites will pass signals among themselves and to the ground via free-space optics. The space interconnections will include 48 links of 200 Gbps apiece, as well as 72 steerable up/down links to Earth at 100 Gbps. (my emphasis)

edit: Confirming that the plan is to establish several dozen laser communications link between ground stations and satellites, from the article The Speed of Light: Laser Light and Optus Explain Optical Communications Partnership:

  Laser Light’s hybrid network is broken into two elements: an OSS part and the Ground Network System (GNS). The OSS half is comprised of a constellation of eight to 12 Medium Earth Orbit (MEO) satellites, which beam down data to a GNS via a completely optical spectrum. The data then connects to terrestrial fiber infrastructure, such as the one Optus already has in place. (my emphasis)

above: Graphic from The Speed of Light: Laser Light and Optus Explain Optical Communications Partnership to Via Satellite Magazine Note: since the satellites are in medium Earth orbit (MEO) and not Geosynchronous orbit (GEO), these beams would not be fixed, but in fact scan repeatedly through tens of kilometers of airspace each.

These would not be narrow, millimeter-diameter beams like we see from laser pointers. In order to combat diffraction, they would actually be expanded to at least tens of centimeters in diameter or larger. There is also a chance they would be just outside the visible wavelength range in the (very near) infrared. So I would guess there is a good chance that - depending on the actual implementation - these beams might not actually pose any risk to a pilot if an aircraft passes though one, but I don't know that for a fact.

I would like to know who must approve globally distributed continuous laser data links between Earth stations and orbiting Satellites in the context of aviation safety.

The answers to the related question How does aviation deal with satellite and Moon laser ranging, and other scientific lasers in the sky? seem to suggest that there are some rules and best practices associated with ground-based lasers from observatories that are used intermittently, but in the case of bidirectional, near continuous laser traffic from dozens to perhaps hundreds of sites (each satellite has 72 independently steerable beams) the existing procedures (having two human spotters watching for planes) would not really be feasible.

There is some discussion here but I don't see any mention of aviation.


texts: Do you need a commercial rating for aerial application work?

texts: So to be qualified to do aerial application work do you have to have a private license with a commercial rating?


texts: How did aviation industry come to know about the drastic difference in air pressure in high altitude?

texts: After watching many documentaries about air plane crashes, it seems that aviation industry learned many of its lessons from disasters. For example, from the 2 mid-air explosion of de Havilland DH 106 Comet in 1950s they learned a lot about metal fatigue that can cause Explosive decompression. So, I'm curious to know how did the industry come to know about the drastic difference in air pressure that occurs in high altitude? Was the knowledge already there before an airplane was even invented?


texts: What is the most economical way to store a small aircraft in a place with severe weather?

texts:
I'm interested in possibly owning a small aircraft sometime in the future.  In the interest of finding out how much money it would cost, I recently called a local FBO and asked about a hangar rental.  I was told that it starts out at over $300 per month and that there is an 18 month long waiting list to get one!  I am talking about an older used piston engine plane, not a private jet.

I'm quite aware of the fact that it is money, rather than aerodynamics that keep a plane in the air, and I'm getting the impression that it takes a lot of money to keep a plane on the ground, too.

The only other thing I know of is to tie it down, which I was told costs $150 per month at this same FBO.  The issue I have with that is concern about the weather.  I live at high elevation; the summer sun is very intense, thunderstorms and hail and common in the summertime and winter brings plenty of snow; sometimes up to two feet at a time.  Temperatures fluctuate from about 0 to 100 degrees Fahrenheit.

I was wondering if there are ways to effectively protect an aircraft from the elements while it is tied down, or if there may be some more cost-effective storage solution than a rented hangar.


texts: Could airliners fetch data like AoA and speed from an INS?

texts:
If I understood what an inertial navigation system (INS) is, it should be able to calculate speed and orientation of the aircraft.
If this is possible, why do airliners solely rely on sensors to measure speed and angle of attack (AoA)?


texts: ICAO and EASA classification of instrument approaches

texts:
ICAO distinguishes approaches operations based on DH between 'Type A' (DH >= 250 ft) and 'Type B' (DH < 250 ft), which are further divided into subcategories. From the Annex 6 — Operation of Aircraft Part I:

a) Type A: a minimum descent height or decision height at or above 75 m (250 ft); and
b) Type B: a decision height below 75 m (250 ft). Type B instrument approach operations are categorized as:

Category I (CAT I): a decision height not lower than 60 m (200 ft) and with either a visibility not less than 800 m or a runway visual range not less than 550 m;
Category II (CAT II): a decision height lower than 60 m (200 ft) but not lower than 30 m (100 ft) and a runway visual range not less than 300 m;
Category IIIA (CAT IIIA): a decision height lower than 30 m (100 ft) or no decision height and a runway visual range not less than 175 m;
Category IIIB (CAT IIIB): a decision height lower than 15 m (50 ft) or no decision height and a runway visual range less than 175 m but not less than 50 m; and
Category IIIC (CAT IIIC): no decision height and no runway visual range limitations.

Instrument approach procedures are further classified as follows:

Non-precision approach (NPA) procedure. An instrument approach procedure designed for 2D instrument approach operations Type A.
Approach procedure with vertical guidance (APV). A performance-based navigation (PBN) instrument approach procedure designed for 3D instrument approach operations Type A.
Precision approach (PA) procedure. An instrument approach procedure based on navigation systems (ILS, MLS, GLS and SBAS CAT I) designed for 3D instrument approach operations Type A or B.

If I understand correctly, EASA would like to implement similar concept (as stated in 'Notice of Proposed Amendment 2018-06(C)'). On page 51, there is a summary table with classification of approaches:

From the table above, how can Category I/II/III approach be 'Type A'
approach (green rows)? I thought that from the definition, only 'Type B'
approaches have subcategories.
What kind of approach would be LIRN ILS Z RWY 06 (see the chart
below)? What kind of planning minima should I use?


texts: Is the FAA expected to issue more regulations soon on drone usage in rural areas?

texts: There are exponential increases in funding for small drone startups.  When is the next publication period for the FAA to issue regulations on use of small drones in suburban areas?


texts: Under what conditions can the maximum angle of climb be achieved for jet and propeller aircraft?

texts:
I know that the maximum angle of climb is reached at maximum specific excess thrust (S.E.T.) for jet airplanes, or minimum drag or maximum $\frac{L}{D}$.

Is this true, and if yes, is this valid also for propeller airplanes, or is $\gamma_{max}$ reached at another condition for props?


texts: Does international mail go in passenger planes?

texts:
I have a shipment from Canada to South America coming, and it's curious that the "priority" FedEx option takes 6 days to arrive, when there are daily flights between the two destinations.

So I'm assuming mail does not go in airliners.

Am I right, and if so, what's the reason for that? It seems it would be extremely more efficient at least for small shipments.


texts: Is the Cirrus Vision SF50 the only civilian monojet currently on production?

texts:
Since the Piper PA-47 and Diamond D-jet never made it past prototype stage, is the Cirrus Vision the only single engine civilian turbofan jet in production?

What other monojets have made it into production?


texts: What are the BUGS and RST buttons on the A320's ISIS for?

texts: What is the BUGS and the RST function for the A320's ISIS for?


texts: Do GA gasoline engines have a tendency to cough, and splutter?

texts:
I'm wondering if GA piston engines have a tendency to stall like some old carburetor car engines if the throttle is increased too quickly.

What would happen or what could be done if this scenario occurs?

When it happened in cars sometimes you could not restart until the residual fuel was burnt by cranking the engine for some time. Does this apply also to aviation engines?

The question arises from the fact that the design of the engines are quite old from my understanding.


texts: How do the military pilots of Air Force One train for exceptional circumstances in an airliner not designed for high performance?

texts:
This article discusses how on one occasion, the pilot of Air Force One, the personal air transport of the President of the United States, was required to perform evasive manoeuvres to avoid presumed hostile fighter aircraft over Syria. In reality, the Syrian aircraft were friendlies and their military authorities had merely failed to properly communicate their intent. But nevertheless, it shows, and is logical, that the pilots of these converted civilian aircraft are required to learn and perform techniques that would never be used in the intended civilian operation of these aircraft.

How do pilots learn to fly an airliner, like the VC-137 in use at the time of this anecdote, or in the present day a 747, beyond its intended use and presumably with a high risk of failure? Does the United States Air Force retain identical aircraft not routinely used as Air Force One, for specific training use? Otherwise, how is it determined that these manoeuvres are feasible in such an aircraft and that the pilot is capable of performing them?


texts: How to find the measurement of how far Tail plane to Center of gravity of the aircraft?

texts:
How do you find the measurement of Piper Archer Tail Plane distance to the center of the gravity.

Google really doesn't help me... maybe you guys know some website that has databases of small aircraft.

Thank you very much and best regards,


texts: What's the difference between 'modification' and 'corrective action' in an AD or SB?

texts: For example Modification of an airplane in accordance with the instructions of the specific SB as specified in Table 1 of this AD, as applicable...


texts: Can the FAA stop the municipality owned airport from closing down?

texts: I live in Wheeling IL. Our town owns the municipal airport there. Most of the residences here want to close down the airport. Can the FAA stop us from closing the airport?


texts: Why there is a helicopter sitting north of madras, OR, , above the warm springs reservation every single night?

texts: Every night I see a helicopter light above the reservation sitting in a spot above my house, but way up that I can't see it closely, just the light.  Has to be a helicopter since it sits in one spot.


texts: Why do we always use circular nozzles for commercial aircraft engines? Other shapes like rectangular nozzles are used in military aircraft, e.g., Raptor, Nighthawk.


texts: Calculating distance from VOR station with radial and heading

texts:
I am currently struggling to understand the following question regarding a VOR station and an aircraft. The aircraft is found in the 30 degree radial from the VOR station at time T(1) and T(2). During the 10 minutes between T(1) and T(2) the aircraft maintains a heading of 120 degrees from magnetic north at 120 knots ground speed. The question goes like so:

  At time t(1) an airborne VOR receiver shows that the aircraft is on the 30deg radial from a VOR station. The pilot maintains a ground track heading of 120deg with respect to magnetic North and 120 knots ground speed. At time t(2) , 10 minutes later than t(1) , the VOR receiver indicates that the aircraft is on the 30deg radial from the same station.
  Assuming no errors, what is the pilot’s distance from the VOR station at time t(2) ? If the pilot had access to airspeed, can the range be determined from the VOR measurements? Can it be determined if the pilot had access to ground speed and ground track heading?

I'm not quite positive of my understanding of the situation. To my understanding the heading indicates the direction the aircraft is pointing in is 120 degrees with respect to magnetic North however its course must be either be 30 degrees with respect to magnetic North or 210 degrees with respect to magnetic North, allowing it to stay in the station's 30 degree radial. Would my understanding of the situation be correct?


texts: What examples of Janitrol heater failures can be found in NTSB reports?

texts:
What examples of failures in Janitrol heaters can be found in NTSB reports?

As a bit of background, the gasoline heater is a small, gasoline-fueled heating device commonly found in light twin aircraft such as the Cessna 414.

What I'd like to do is compile a list of the associated NTSB reports for all known failures of Janitrol heaters that caused an incident. I'd also like to note which cases had a favorable result and what actions the pilots took to handle the situation.

The answer may eventually lead to a discussion of depressurizing the cabin of pressurized aircraft to put out a fire. While this approach won't work with some fires, it might apply to this situation. This question about in flight fire is relevant to that discussion.


texts: Why do Russian jets make a squealing sound?

texts:
Why do the engines noise from the Russian and Soviet jet create a squealing sound which is very distinct which most of the western jets don't have? Which part of the engine creates the noise, and why is it so distinct to Russian engines? Also it appears to be dominant in low rpm or at idle throttle setting.

You can hear this in the video MiG-29 start-up to shut down (4 min mark) .


texts: Is there a Non Directional Beacon(NDB) morse code sound database?

texts:
I need to know what is the morse code sound of:

CALL: OZ
Khz: 212
QTH: RUCKR
lat: 31.2292
long:-85.7917

I found this website, but I could not find the sound of different NDBs:
http://classaxe.com/dx/ndb/rna


texts: What is the difference between reversible and irreversible controls?

texts: What is the difference between reversible and irreversible controls ?


texts: Why are true and indicated airspeed different?

texts:
So, I understand that True air speed is the motion of aircraft relative to air around it. And, indicated airspeed is speed arising due to dynamic pressure.
Considering a true airspeed of 100 knots, that means the air molecules are striking the aircraft at 100 kt/ vice versa.
Shouldn't this make true and indicated airspeed same?
Also with constant indicated airspeed, why does true airspeed increase with altitude? Shouldn't it remain same?


texts: Why do different manufacturers recommend different throttle settings at startup?

texts:
I was wondering why different engine manufactures recommend different throttle openings before engine start? On many Pipers 1/4 Inch is recommended while the Cessna 172N recommends 1/8 Inch and the Cessna 172S again recommends 1/4 Inch.
Why do we open the throttle before starting the engine? What difference does it make opening the throttle more or less, has it to do with the fact that it isn't good practice to have high engine power when the engine is still cold and oil pressure is low? And why should we open the throttle differently when the engine is flooded or we start the engine when it is still hot?


texts: What does automatic pitch trim is available mean, when bank angle is below 33°?

texts:
I was reading about the bank angle protection mode in an A320. I have a few doubts about it.

I know that if the bank angle exceeds 33 degrees then automatic pitch trim is not available and hence of the side stick is released the aircraft would come back to a bank angle of 33 degrees and stabilise. But I don't understand what happens if the bank angle is BELOW 33 degrees. I read that the automatic pitch trim is available. What does that mean?


texts: Does Buoyant Lift Force scale with Load Factor?

texts:
Let's say I am flying an airplane that has a weight of 100,000 kg with a 1G load factor at normal steady flight. I have helium lift assist that is providing 50,000 kg (50%) worth of buoyant lift force upwards. Therefore, my aerodynamic lift has to provide 50,000 kg (50%) of upwards lift to remain in flight.

If I go into, let's say, a 60 degree bank maneuver and induce a 2G load factor to the airplane (so now the perceived weight goes up to 200,000 kg), does the buoyant lift force scale in some manner with the load factor, or is the lift force completely static and continue to provide 50,000 kg worth of positive lift regardless of the induced load factor? In other words, does the aerodynamic lift have to provide 150,000 kg of positive lifting force during a 2G maneuver to keep the plane airborne?


texts: How does the power transfer unit in the A320 work?

texts: As far as i know the function of a PTU is to power one hydraulic system (either green or yellow) that is experiencing low pressure driven by pressure from the other system which still has the normal 3000 psi, where no fluid transfer happens. I have read (correct me if im wrong) that this happens with the help of hydraulic pumps, but how exactly does the "power" transfer happen?


texts: Why are some Tomahawk missiles' nose duck-nose shaped?

texts: Why there is a duck-like shape in this Tomahawk missile's nose?  I see this shape in most Tomahawk images; however, not every Tomahawk's nose is shaped like this.  If it is an aerodynamic feature, what is its common name?


texts: Is it OK to move a light aircraft by pushing or pulling the propeller?

texts: It's very common to see pilots moving a light aircraft by pushing or pulling on the prop, either because there's no tow bar available or simply out of preference or convenience. Is this a reasonable thing to do or can it damage the prop or engine in some way?


texts: Are there roll control devices other than ailerons?

texts:
With the little that I've learnt about aeroplanes, I know that the aileron is the control surface that a pilot use to roll the plane by decreasing the lift of one wing and increasing the lift of the other wing. And it's (aileron) generally located at the wing trailing edge.

Now, if the wing tip is made flexible (or hinged to the wing), can the wing tip serve the purpose of an aileron by lifting the wing tip upward or downward?


texts: Can the fuel on the wing cause the aircraft to destabilize?

texts: If fuel is stored in the wings, which are in constant movement during the flight, can the fuel unbalance the aircraft?


texts: How does engine exhaust temperature affect contrail formation and why?

texts:
There was a german study about the "Influence of propulsion efficiency on contrail formation". In this study, an Airbus A340 and a Boeing 707 flew right next to each other.

  The two contrail forming aircraft were

  (i) a Boeing B707 equipped with four jet engines of type JT3D-3B with bypass-ratio of 1.4 and

  (ii) an Airbus A340-300 with four jet engines of type CFM56-5C4 with bypass-ratio of 6.8.

The A340, with the high bypass-ratio, formed contrails behind it, whilst the Boeing with the low bypass-ratio did not form any contrails behind.

Source

This has to do with the different exhaust gas temperatures of engines with different bypass-ratios.

How exactly is the formation of the contrails affected by the EGT (and therefore bypass-ratio), so whats the difference between low EGT and high EGT in terms of contrail formation? What is the physics behind it? Just why does the Airbus form a contrail, whilst the Boeing doesn't?

Note, 'How does contrail formation differ from turbofan to turbojet?' does not answer the question regarding the EGT.


texts: What does the orange colored text in a SkyVector route indicate?

texts:
If you use a pre-made route in skyvector.com, sometimes there will be orange text.

For example: from KIAD to KTPA with default cruise settings, the second route in the list will have DADES6 in orange.

What does this mean and how would you program these into the FMC?


texts: Why is the King Air avionics switching system wired normally closed?

texts:
In the King Air 200 and B200 (perhaps other King Air models as well), the avionics electrical bus relays are normally closed. With the Avionics Master switch in the "OFF" position—which is electrically closed—when the Battery master switch is turned on, DC power is supplied through the closed Avionics Master switch to the avionics bus relay solenoids causing these relays to open and disconnect the avionics buses from DC electrical power. Subsequently selecting the Avionics Master switch to the "ON" position opens the switch which disconnects the DC power to the avionics bus relay solenoids, allowing the relays to default to the closed position thereby supplying DC power to the avionics buses. The checklist action item for the Avionics Master switch power failure is to pull the 5 amp Avionics Master circuit breaker, which electrically opens the avionics master switch circuit thereby restoring DC power to the avionics buses.

See the following circuit diagram:

(Source: own work)

This system works, and works well, by all appearances. However, the design does seem to be somewhat counter-intuitive.

My question is, what is the purpose of designing the avionics master switching system normally closed?

Despite being counter-intuitive, I can understand that the electrical loads required by the avionics demand the use of relays, and that the design allows for the relay solenoids to be powered for a minimal time. I think this is the most reasonable explanation for the design, but I am looking for documented confirmation. Is there some other design consideration that I have overlooked? Does anyone know of a documented reason for this design?

NOTE: While you are welcome to speculate with me on this issue in the comments or chat room, I am not looking speculative answers. I am looking for an answer coming from persons familiar with the King Air electrical system and preferably backed up with documentation, such as the maintenance manual, or other sources that I have overlooked.


texts: (Ref AC 61-65H solo endorsements 61.87(n) and 61.87(p)). When should I give 61.87(n) vs 61.87(p)?

texts:
At first, it seems clear (according to AC 61-65H) that 61.87(n) is for the first 90 calendar-day period and 61.87(p) is for each additional 90 calendar-day period. However, when I look up the actual regs, it says: "(n) Limitations on student pilots..." and "(p) Limitations on flight instructors..."
So, now it seems like (n) should be the only 90 day endorsement. (p) are just the rules the flight instructor has to follow (every time). So don't (n) and (p) always go together? And, is this idea that we start with (n) and then use (p) if 90 days go by...incorrect? Dare I say, should there be an AC 61-65I that corrects this? And, what should the endorsement say?
I see the NAFI guide sets up the question the same way the FAA does (initial vs additional 90 days), but they just use (n) for both of them.


texts: How much humidity is being maintained in cabin and cockpit of B787?

texts: I think in general there is less than 10% humidity is being maintained in most of the commercial aircraft but I think they have improved that in the 787. I am not sure how much that is and if the cabin and cockpit have same amount of that?


texts: Do logged hours with a Sport Pilot instructor count towards a private pilot certificate?

texts:
I've my Sport Pilot licence and I've got logged hours with a sport pilot instructor that isn't a private pilot instructor.

Can I use my logged instruction hours in order to upgrade to private pilot?


texts: What are airline "flag" and "supplemental" operations?

texts:
I constantly see regulations which refer to "flag" and "supplemental" operations.  For example:

  14 CFR 121 — OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS

  Subpart Q—FLIGHT TIME LIMITATIONS AND REST REQUIREMENTS: DOMESTIC OPERATIONS

  Subpart R—FLIGHT TIME LIMITATIONS: FLAG OPERATIONS

  Subpart S—FLIGHT TIME LIMITATIONS: SUPPLEMENTAL OPERATIONS

What exactly are they and how are they different from "normal" Part 121 operations?  I can't seem to find them defined in Part 121 or 1.1 (definitions).


texts: What qualifications does a commercial aircraft pilot need?

texts: I have been considering becoming a pilot or first officer but I am unsure as to what qualifications are needed to pass the exams etc. Could someone please tell me?


texts: Why is the pitot tube located near the nose?

texts: The pitot tube located near the nose could be affected by the boundary layer and could increase the error. Then why is the pitot tube located near the nose?


texts: How do the contrarotating turbines work in the F-119-PW-100?

texts:
I was reading about the F22 Raptor and found out that its powerplants use  contrarotating turbines. How does this work

Also, if the spools and their connected compressors are rotating in opposite directions, won't the stators and their angles and such be different?

And, if it reduces a row of stators then the compressor which acts as a stator in the last stage, how does it change the AOA according to the flow rate, if it works like a stator?

Also, the F119-PW-100 has 3 low pressure compression stages and 6 high pressure ones. Which means it should have 10 stator stages. So, if a row of stators goes away, how many stator stages remain.

I'm sorry if I'm wrong somewhere or I reached conclusions which aren't right. I'm a 16 year old enthusiast, and I'm just curious.