texts: ADS-B receiver, dongle vs SBS-3 or Garmin

texts:
Is there any differences between FlightAware Pro Stick USB and Kinetic SBS-3 or Garmin for aircraft tracking purpose?
Something like: SBS-3 can receive twice more data.. is there any benefits?
Assume, that I have power PC.


texts: Why aren't 737s or A320s commonly used for transatlantic flights?

texts:
Despite newer models of the 737 and A320 families having more than enough range to cross the North Atlantic (and also most of the older models, if they refuel at Gander and\or Shannon along the way; the only one for which this isn't the case is the 737-100, which would require an additional fuel stop in Keflavik, and which is, in any case, no longer in service anywhere), 90% of transatlantic passenger flights are by widebody jets, with 757s accounting for most of the remainder; only 1% of transatlantic commercial flights are by smaller narrowbodies like the 737 or A320.

Given that all A320s and all Next Generation\MAX 737s can fly nonstop between the U.S. east coast and western Europe, and that even the older 737s can fly between the U.S. and Europe if they make a stop or two along the way to refuel, why are the smaller narrowbodies so rare in transatlantic flight, when the prospect of using these smaller, cheaper, more flexible (operationally-speaking, that is, not physically more flexible) aircraft to fly passengers across the Atlantic would seem to be very attractive to airlines, especially low-cost airlines (for instance, Southwest or Ryanair)?


texts: How much are noise-related landing costs for a long-range aircraft at Heathrow?

texts:
I am trying to estimate the noise-related costs for a long-range platform aircraft (for example, the Boeing 787) at Heathrow Airport.

I have found the following table (PDF, page:24) outlining some costs for night/day landings, but can anyone tell me which 'chapter' a B787 would considered? I have looked around extensively, but cannot find any clear explanation on this.


texts: Does a flight briefer require a license in the US?

texts:
Flight briefers have to stay on top of a lot of different variables. In order to give a pilot the information they need for their flight they must be able to interpret weather forecasts, keep on top of any ATC delays, and wade through all the NOTAM's to find the ones relevant to the flight plan.

The skill set overlaps with those of flight dispatchers. In the US flight dispatchers are required to have a certificate. Are flight briefers required to have a license or certification, either a dispatcher certificate or some other credentials?


texts: Do wind tunnels with flow straightener after the flow contractors have slower flow velocity compared to a wind tunnel with the flow straightener right after the fan? Note: I'm assuming the same fan is being used.


texts: What changes are needed for a piston-prop aircraft to withstand saltwater environment?

texts:
I'm interested in WW2-era piston-prop aircraft. I want to know what changes are needed to make the aircraft withstand saltwater corrosion. Presumably these are different and more expensive than the normal land versions of aircraft, or they would make them that way in the first place.

I'm not interested in the usual carrier modifications, like tailhooks and wing-folding. For this question, I'm only interested in withstanding saltwater corrosion.

I have heard that aluminum resists saltwater corrosion very well. Not so sure about steel or wood. Are there differences in the air intake? What about certain delicate instruments like a pitot-static tube?

Edit: I was envisioning any combat aircraft that fight over the ocean, but especially the more exposed stuff like low-level torpedo bombers and seaplanes since they land directly on the water. Carrier aircraft is fine too.


texts: Why don't airliner winglets have consumer advertising on them?

texts:
I was looking over the wikipedia article for the 737NG when I came across this picture:

As you can see, the operator of the jet has written their companies web address on the winglet.  Which seems like a waste, I'm already on their airplane, there's no need to sell me, it's not so much an ad as a reminder at that point...

So, I couldn't help but think, when looking at it, that it would be somewhat clever if RedBull bought the rights to advertise on a 737NG and wrote something on that spot that said, "Redbull gives you winglets" (rimshot).

Sillines aside, there is a serious question here.  Generally speaking if there is a public surface that many many people will be forced to stare at for any length of time, then there is an advertisement there.  Bus stops, billboards, the sides of buildings, there are ads virtually everywhere.  Heck, commercial aviation equipment even has a few already with some of the jetways you see at airports:

There are tens of thousands of people who see winglets every day (and even more who see winglets in travel pictures, blogs, etc), so why aren't advertisers taking advantage of the space and, further, why aren't airlines trying to sell the space in order to increase revenue?

I'm wondering if perhaps there are regulations that might make this difficult?  A good advertising spot will change images and products fairly frequently.  On a winglet that would necessitate either a new paint job or, perhaps, a new vinyl wrap (like what is used in NASCAR.)  And I'm wondering if the regulations for commercial aircraft regarding how the winglets are painted would prohibit this sort of "quick switch" activity (are wraps even legal)?  Or perhaps there is a certification process for all new paint jobs that would make it so the amount spent to advertise would never match the increase in sales?

Or is it just that airlines have a sense of pride about their aircraft and respect their passengers enough to not bombard them with ads?  (...yeah, I doubt it's this last one as well ;-) ).

Edit:  I did mark this one for FAA Regulations, but I feel EASA regulations should be similar enough to give some insight as well, so if you want to answer with those regs feel free.


texts: How many pilots are licensed in Hong Kong?

texts: Title says it all. I don't see this information online anywhere. A breakdown by PPL/CPL would be nice. I have a vague memory of someone telling me 300 but that seems a tad low for a city of 7.5 million.


texts: Cessna 172/182: Should I set the tank selector to the R.H. tank after parking the airplane?

texts:
The single-engine Cessna 172 and 182 aircraft models have a dual gravity-fed fuel system, where you can draw from both the LH and RH tank simultaneously in flight.

I've heard it said that when you are securing the airplane after a flight to leave the tank selector on the RH tank to prevent crossflow if the ramp is uneven. (So you don't end up with all the fuel in one tank).

Is there any merit to this?  Does it actually block the crossflow valve to do this?


texts: Was a 7300-mile non-stop flight possible in 1979?

texts:
I'm listening to the On Wings of Eagles audiobook by Ken Follett and found some information about a non-stop transatlantic flight between Teheran (IKA) and Dallas (DFW). GCM says that this is 7,300 miles and Google says that's 11,750 km.

Was there any aircraft capable of performing such a flight in 1979? If yes, then which one?

It was expected to travel with about 10-15 people on board and non-stop flight seems to be essential (at least to the author, because I completely don't understand the reasons why such a flight couldn't take a re-fueling break at some European airport once clear of the dangerous zone of Iran's / Middle East's airspace).

The author's choice of either a Boeing 707 or 727 seems to be completely incorrect, as according to Wikipedia there wasn't any version of either of those aircraft capable of flying 7,300 miles non-stop (or I'm missing something). The longest range mentioned is 10,650 km in the case of the B707-320B.


texts:
Is a high alpha sideslip possible and safe?

We use a sideslip to increase drag when trying to reduce altitude before landing on a short runway, etc., which is crossing your rudder and ailerons, to produce an angle to the intended direction, usually in level flight.

Is it possible to do a sideslip at an AOA of say 15 deg for even more drag, assuming stall angle is at 30 deg?


texts: How do planes maintain constant speeds at cruise altitudes?

texts:
I'm a noob so pardon my ignorance. So my understanding is that as the plane gets lighter during the flight, its mass reduces therefore reducing the lift needed to maintain the altitude. At those altitudes and speeds, my understanding is that we can't engage slats or flaps. As a result, we would have to reduce thrust to reduce the lift to account for the loss in fuel and maintain the same flight level

So what can one use to continually reduce lift coefficient at those altitudes to maintain constant airspeed and flight levels? I understand that ATC also clear aircraft to higher FL thereby reducing the air density and therefor reducing lift and enabling higher airspeed but that still leaves us with the problem of flying at constant airspeed at cruise altitudes.


texts: Is it possible for a fighter jet to shoot itself down with an IR missile?

texts:
In this answer, it's mentioned that

  However, IR missiles (AIM-9 Sidewinder, AA-11 Archer, MICA IR, ASRAAM) do not emit any EMR that indicates they're incoming; they use a passive FLIR sensor to identify and track the heat source they were told to kill (they don't even require a radar lock; the seeker can be cued to a pilot's helmet, or it can be "uncaged" and will lock on to the most significant heat source in front of it).

Emphasis added.

Given this, is it possible, given some very bad luck, for a fighter jet to fire an IR missile, only for it to get turned around somehow (for instance, by some sort of momentary combustion instability in its rocket motor, or by some very bad turbulence) and end up locking onto and shooting down the jet that fired it?


texts: Whats the difference between a paragliding rescue chute and a parachute?

texts:
Whats the difference betweem a paragliding rescue chute and a parachute and could I use a parachute as a paragliding rescue chute and what would be a disadvantage/advantage?

At least these points are imortant: Stablity, descent rate, manoeuvrability, opening speed, reliablity.

I'm asking because I've found articles (in german) which make the argument that the current rescue systems for paragliders are a mistake and that "BASE systems" are starting to beeing used in the acro scene. However I could not find details.

dhv.de -> Rettungsgeräte
x-dreamfly.ch -> Retterproblematik

Paragliding rescue chutes are typicly round canopies but there are also other special forms.

Military troop parachutes are also round canopies.

So are chutes used for space exploration.

While parachutes are rectangular.

And also paragliders are rectangular.

Round canopies are said to have a slower descent rate, are more stable then other forms, are simple and open faster and are small but they are not feasible to manoeuvre but I could not find references to back up those claims.


texts: What is the maximum amount of flight hours an aircraft can have a month?

texts:
The reason I ask this question is because I am a programmer and developing ETL processes to calculate reliability of products that are installed in aircrafts.

I have been getting A lot of bad data from the OEMs.

I have been told by an engineer at my organization that the maximum number of flight hours an aircraft can have is 400 hrs a month.

Is this accurate per FAA regulations?


texts: Why does RPM for a fixed-pitch propeller change with an aircraft's pitch?

texts:
Talking bout a C-152 -

If I pitch the aircraft down, and without adjusting the throttle, the RPM would show an increase. Pitch up, and without adjusting the throttle, the RPM shows a decrease.

I've been told that by pitching down you increase the amount of airflow your engine is receiving while pitching up decreases the amount of airflow, or that the propeller at different pitch attitudes either forces more air or acts against the air entering the intake ports, or that it's because of the propeller angle of attack.


texts: What is the maximum acceptable gap between the jet bridge and airplane door?

texts: I noticed on an American Airline flight a gap of about 4 inches between the floor of the bridge and the airplane. Wide enough that if the passenger is not paying attention to the floor the foot may slip in between or at  least get stuck.  The flight attendant said there's always a gap. I've seen a gap but not that wide. Is there a maximum acceptable gap?


texts: Why do different aircraft have different maximum operating temperatures?

texts:
I was reading this Wired article about the recent Phoenix heat grounding some jets. It's a great read on why heat is detrimental to lift, but it raises a point it never answers (emphasis mine)

Phoenix just provided another reason to hate flying: the heat. With temperatures there expected to hit 119 degrees Fahrenheit, airlines canceled more than 40 flights today.
Wait. What? Airplanes can't fly because it's too hot? That's crazy.
No, not really. According to news reports, the heat poses a particular problem for the Bombardier CRJ airliners, which have a maximum operating temperature of 118 degrees. Bigger planes from Airbus and Boeing can handle 126 degrees or so.

Is this solely due to the size of the aircraft, or is it a difference of manufacturer?


texts: Are helicopters expected to follow the lateral guidance of taxiways in a hover taxi or air taxi?

texts: If a helicopter is asked by ATC to hover taxi or air taxi, are they still expected to follow the lateral guidance of taxiways on the ground, or do they proceed "as the crow flies", direct to their destination?


texts: What measurement units are used in Boeing FDR readouts?

texts:
I am working with FDR readout data and I am trying to find good resources about measurement units for those logs. The data seems to be a mix of SI and non-SI units and it can be quite difficult to work with data if you don't have correct units.

The data comes from Boeing 757, 767 and 737MAX aircraft but I am not sure what type the FDR equipment is installed (will find out at some point).

Does anyone have a good resource on this?

I am using this data to create graphs and measurements in Elasticsearch and Kibana, focusing on fuel efficiency. It is quite interesting to see how fuel flow is different between engines and how altitude affects fuel consumption.


texts:
I read about several aircraft crashes throughout aviation history and the investigations on wikipedia and also checked out some episodes of the documentary "Air Crash Investigation".

While of course I can only make conclusions of what I read, hear and see it appears, that problems related to communication are one typical reason to contribute to such disasters.

Something that attracted my attention is that the sidesticks used in the aircrafts of Airbus seem to be involved in not less than three crashes including Air France Flight 447.

Though there is the general distinction pilot flying (PF) and pilot not flying (PNF) failures, malfunctions and the triggered warnings tend to create a situation of stress and strain in the cockpit as comprehensible. Confusion comes up not seldom in such situations.

My point finally is, that

Sidesticks are smaller than yokes. To apply a control input one only needs to turn one's wrist while a yoke requires you to use both of your arms to make the big aircraft turn. I wonder if the inhibition threshold therefore is somehow lower to make extreme, exaggerated inputs in case of a sidestick?
Secondly, and this is the major question, as it appears, the sidesticks make it much harder, to be aware of the currently applied control input (especially) for the other pilot. While the yokes of both pilots are physically connected and both pilots have direct feedback of the currents state at any given time, the sidesticks

give no feedback to the other sidestick
are smaller, which makes it harder to see the current state their in already by the size alone
are more distant than yokes making it again harder to see for the other pilot, as this A380 cockpit shot shows

Question:

How is the general assessment of those sidesticks concerning safety?
Is there any feedback to the pilots which stick is giving what input?
Has there been any development in improving this situation?
What are the accidents/incidents sidesticks more or less contributed to confusion/lack of information?


texts: When must full aircraft registration be used as radio callsign?

texts: What are the FCC or FAA regulations that require one to use their full registration as radio callsign, unless abridged by air traffic control, when using an aircraft radio for transmitting?  It seems it is becoming popular to use type of aircraft and color only for transmitting.


texts: How can you fly at 0kts without stalling?

texts:
At 0g, stall is theoretically impossible.

In practice, can a maneuver be performed that, by bringing the aircraft to, or very close to 0g, also brings the aircraft to a temporary standstill, or near standstill, in terms of true air speed?

Can such a maneuver be performed without exceeding 30° pitch?

If so, how?


texts: Why was F-18 chosen to escort Space Shuttle Endeavour?

texts:
This question is kind of a continuation to Why does NASA have F/A-18s?

The accepted answer states that

  "NASA uses them for pilot training and as chase planes for research
  aircraft."

So, why was F/A-18 chosen for the Space Shuttle, among ton of other options available (all aircraft with 2 seats)? Also, I would like to know why NASA got F/A-18 in the first place, out of the rest.


texts: What is the difference between a Boeing Line number and a Block number?

texts: We know that every Boeing aircraft has a Line number, Block number, and MSN number. I want to know what what does it mean by this Line Number or Block number. and what are the difference among these terms.


texts: How to convert a PPL (Gyrocopter) to a PPL (Helicopter)?

texts: If I have a Private Pilot License (PPL) for gyrocopters, and I want to convert it to PPL for helicopters, are my flight hours in the gyrocopter considered for me as flight hours in helicopters?


texts: Are requests for an emergency landing ever refused?

texts:
Under what circumstances might it happen that a pilot's request to make an emergency landing is refused?

Is such a thing known to have occurred?


texts: What is the production status of the Pipistrel Panthera as of March 2017?

texts: What is the production status of the Pipistrel Panthera? They had plans to start production in 2016/2017 but nothing new has been published in the last two years.


texts: How effective are modern aircraft at clearing smoke?

texts:
In reference to this incident by a certain (in)famous artist, i'm wondering how effective modern aircraft are at clearing smoke for single aisle commercial aircraft such as B737/A320 or a business jet like in the story?

Which direction does the airflow in a cabin move? Top to bottom?
How far are people effected by secondhand smoke if somebody lights a cigarette? Would it be within a one-meter range or would people notice across the whole cabin?


texts: Is there any combination of aircraft and airports where no alternate landing airport would be possible?

texts:
In the comments on this answer an interesting assertion was made, that you never have a situation in the US where there is no possible alternate airport.  Assuming that:

you're flying an aircraft that is normally flown for commercial reasons,
you're flying to an airport that normally allows flights to land,
you're flying from an airport in the US to another airport in the US,
and you're following the regulation that you have to have enough fuel to get to your destination, then fly to your alternate, then stay in the air for another 45 minutes

is there any combination of aircraft and airports where no alternate landing airport would be possible?


texts: Can flight control computers detect and help to avoid pilot-induced oscillations?

texts:
With flight control technology available today like fly-by-wire, digitally augmented command inputs etc., I wonder whether any technical solution exists (or could possibly exist) to detect and counter the occurrence and dangers of pilot-induced oscillations (PIO).

Consider for example a low visibility final approach scenario:

Is it possible to detect an early onset of PIO and either augment pilot input to prevent further amplification of oscillations, or, less intrusive, give some (e.g. aural) warning to the pilot?
Also, a fully developed PIO situation might be detected and a warning triggered to increase awareness or prompt the pilots towards an eventual go around, similar to windshear warnings.

If feasible, do such technical mechanisms exist, or would they even be considered helpful by pilots at all? I imagine a critical part to solve would be not to override an actually intended control input by the pilot (that is within the usual safe envelope).


texts: Why are flying-boom tankers restricted to a single boom?

texts:
Tanker aircraft can use one or both of two refuelling systems:

Flying boom: A rigid boom is lowered from the tanker and inserted into a receptacle on the roof of the recipient aircraft.
Probe\drogue: A flexible hose with a (usually) canvas cone on the end is unreeled from the tanker, and the recipient aircraft flies a forward-pointing probe into the center of the cone.

Aircraft can have multiple drogue units...

...but are limited to a single boom.

What prevents a tanker aircraft from having two or more booms?


texts: Could a Combined Inverted Brayton Cycle and rankine cycle engine be used as a power source in a high altitude hybrid aircraft?

texts:
Combined Cycle Power Plant for Hybrid Aeroplane.

Background
Inverted Gas Turbine
From the Institute of Combustion Technology - DLR
MGT = Micro Gas Turbine
IBC = Inverted Brayton Cycle

In the inverse micro gas turbine process, the flow of the individual components occurs in a different sequence than the conventional MGT cycle (Brayton cycle); see Figure 2. In an IBC-MGT, the process air is fed directly into the recuperator (2), heated and forwarded to the combustion chamber, where it is mixed with the fuel and burned (3). After exiting the combustion chamber, the exhaust gas is led through the turbine, where it expands below ambient pressure (4). Subsequently, the exhaust gas is first cooled in the recuperator (2) and then in the downstream water heat exchanger (5), before being compressed to atmospheric pressure in the compressor (1). In this inverse cycle - as in a conventional cycle the turbine again generates more energy than is required for the compression process, so that a generator (6) can be run. As a result of the compression, the exhaust gas is heated, and can thus be cooled down again in a second water heat exchanger (7) in order to exploit as much of the released energy as possible.

Ignore the blue line in the above diagram for the basic cycle without exhaust gas recirculation.
Kalina Cycle
The Kalina cycle is a rankine cycle like a steam cycle. It uses a mixture of ammonia and water. This reduces the boiling point of the mixture.
Description
Air (the green arrows) passes through a heat exchanger and is heated. This heat exchanger acts as a condenser to a separate closed rankine cycle (water-ammonia). Then the air enters an inverted brayton cycle. It passes into a combustion chamber, and then is expanded to subatmospheric pressure in a turbine. The air is then cooled in a 2nd heat exchanger, then compressed, and finally passed through a final heat exchanger and back out to the atmosphere. The work extracted as it expands through the turbine is less than the work taken to compress it.
Meanwhile the water-ammonia cycle is being progressively heated by the second two heat exchangers. This fluid is then expanded through a turbine before passing into the initial heat exchanger/condenser.
The turbines and compressor are linked through a single shaft to a generator that charges a battery or powers the plane.
Operation in Flight
The plane takes off and climbs to altitude on battery power using an electrically powered propeller. Once at altitude it switches from the battery to the combined cycle power plant.
Motivation and Synergies
At altitude the incoming air is very cold this increases the effectiveness of the condenser, reduces its size, and improves the efficiency of the cycle.
Questions

Are the heat exchangers too heavy?
Could we just use a conventional steam cycle in place of the kalina cycle?
Would the combustion chamber need a catalytic section to stay lit?
What combustion temperature would optimise the system?
Could one remove the generator altogether and use this powerplant for thrust?
Would this be better used as a hybrid electric APU because it is too heavy?


texts:
By driving often near my local airport, I deduced that runway lights are kept always on as soon as the day light or weather conditions require it.
I also suppose that it comes from safety reasons established in the past ad that's a worldwide standard.
what I don't understand is why, given nowaday's instrumentation both on ground and airborne, it's not possible to switch them off when no aircraft is ever going to even fly at cruise altitude around it. Here at LIBP (Labruzzo Airport, Italy) we hardly have more than 8 transits during winter so probably 80% of the energy spent by lights it's totally wasted.


texts: Why does the Eurofighter Typhoon pitch up on brake release?

texts:
In the video here of an airshow take-off, it's noticeable that when the brakes are released there's a brief but pronounced fluctuation in pitch as the aircraft accelerates.

This is something you see in very fast accelerating cars / dragsters, but I believe that is caused by the torque through the rear wheels, which is obviously not the cause here.

The same thing can be seen on an F-16 but much less pronounced.

Certainly for the Typhoon, the nose-wheel oleo doesn't seem to be particularly compressed as it's held under braking. I'd guess that you want to ensure that there's no chance even the slightest bit of any upward vector in the engine thrust while you sit on the tarmac, otherwise your brakes might not work, but that doesn't really explain the wobbling.

 source


texts: How does an altimeter deal with the non-linear pressure gradient?

texts:
Altimeters work via an aneroid barometer to sense the atmospheric pressure. If I climb from 2000ft to 4000ft, the altimeter senses that the pressure has reduced by, let's say, 70hpa, and is calibrated to know that 70hpa = 2000ft.

But the pressure gradient (or rate of change of pressure) reduces with altitude. A climb from FL240 to FL260 might result in a pressure reduction of only 30hpa. Yet it still knows that the aircraft climbed 2000ft. How does the altimeter do this?


texts: Is it ok to lift locked armrests on aisle or window seats?

texts: While reading this question, I came across a little trick, of how to lift up the locked arm-rests in window and aisle seats. Though I always wondered why they were locked, knowing that little trick now makes me wonder is it legal to lift locked arm-rests. Would it get me into any trouble with the cabin crews or the airline?


texts: Why changes the lift during turning with sidewinds? Why is there relative wind in the wind-frame?

texts:
I started doing some simulations with XPlane and could observe a very interesting effect when doing turns in the presence of constant wind:

All simulations are done with the XPlane Cessna 172 (?) with the motor turned off in gliding. (I want to simulate an emergency approach)

I control my plane to have a constant glide path angle and a constant roll angle. No coordinated turn. When I do so without wind, I get perfect circles with a true airspeed (TAS) that is decreasing with decreasing elevation. My glide angle controller has not too much work to keep the gliding angle perfectly constant.

However, if I turn on some constant wind, I can observe,

firstly: my circles change to trochoids over ground
secondly: my glide angle controller needs to counteract depending on the relative heading to the wind. When I am in a sidewind situation where the wind attacks the outer (higher) wing, the true airspeed is decreasing and when after a half circle the wind attacks the inner, lowered wing, the true airspeed needs to be increased to hold the gliding angle. In the quarters of turning with straight headwind or tailwind, the true airspeed is equal. So this results in a sine-like true airspeed profile with respect to the actual turning heading.

So in principle, I can imagine, that wind attacking the higher wing increases lift as it raises the whole plane from below and when it attacks on the lowered wing, it pushes the whole plane down from above.

What I don't really understand is why I experience this relative sidewind at all? My plane flies trochoids over ground instead of circles, as the wind blows the whole wind frame away. But shouldn't be the windframe kind of windless with regards to the plane?

My naive idea was, that the whole plane with its own wind frame is moved constantly by the wind, and calculating true airspeed within this wind frame is the same as in the no-wind condition. (see e. g. https://aviation.stackexchange.com/a/26332/30632)

Where do I over-simplify?


texts: Why is Hydrazine used to power the F-16's EPU?

texts: Why does the military use hydrazine to power the F-16's Emergency Power Unit (EPU)? What is so unique about Hydrazine fuel that it's  needed to power the EPU? Why not use a less volatile and less hazardous fuel?


texts: How to calculate airfoil geometry with the maximum lift to drag ratio for a given Reynolds number?

texts: How does one determine the optimal cross sectional geometry to maximize Cl/Cd?


texts: What pilots use VOR navigation: GA pilots, commercial pilots, military pilots? When is it most used?


texts: How are further structural failures prevented if an aft pressure bulkhead fails?

texts: In a modern airliner, if the aft pressure bulkhead experiences a structural failure, what design features are incorporated into the empennage to prevent the empennage from being overpressurized (i.e. at or near cabin pressure vs the normal case, which is at or near outside pressure) to the point of structural failure?  Or, in other words, what keeps the next aft pressure bulkhead failure from blowing the vertical tail, or some other important part, off the airplane a la JAL123?


texts: Planes returned to base after dumping fuel due toilet issues

texts:
A colleague of mine experienced this and I was astonished.
Flying KLM from PVG to AMS a couple of hours into take off toilets became full. The pilot dumped fuel and returned to PVG. All passengers were re-booked next day. Funnily, she had the same issue fly from JFK to LHR last year. (Probability that she was on both planes - amusing)

Thinking of aviation fuel, environment, cost of re-flying passengers. I wonder why the aircraft makers not allow dumping 'contents' of 'toilet tank' (on the open sea) instead of dumping gallons of fuel.

I just wonder how often does such issues happen? Would toilet tank emptying not be checked before take off?


texts: What is the power generating capacity for an airport GPU?

texts:
What is the normal current for GPU power supply for commercial aircraft and how much power do they need while on ground (in kWh)?

I have read that aircraft need need 28V DC and 115V AC - what would be the percentage between both modes of supply?

Would it by possible to power GPUs entirely by solar power?


texts: What's Permaswage / Harrison tube repair?

texts: In modern aircraft, damage of hydraulic tubes can be repaired by Permaswage/Harrison provided by maintenance manuel. However, What is Permaswage / Harrison? It's a name of company?


texts: What is that round antenna(?) on the bottom of a Piper Comanche?

texts: Does anyone recognize this round object under the belly of a PA-24?


texts: How does increasing the size of a jet engine make it more fuel efficient?

texts:
The design trend is there: 8, 4, 3, 2 jet engines on powering the large cargo or passenger aircraft.  Is it mostly to accommodate the larger, more efficient fans, or are there also benefits in the combustion cycle?

Jets seem more immune to the issues of excess heat removal that their piston engine predecessors suffered when scaled to greater size.  Is there a limit to how large an axial jet engine can be?  Are we approaching that limit today with engines such as the GE9X at over $130 \, 000 \, \text{lbs}$ of thrust, or is there more to go?


texts: How do propeller-driven, fixed-wing UAVs counter negative torque from engine rotation?

texts: What cancels the rolling moment produced from the rotation of the engine?


texts: Would a pilot know that one of their crew is armed?

texts:
The Federal Flight Deck Officer page on Wikipedia says this:

  Under the FFDO program, flight crew members are authorized to use firearms. A flight crew member may be a pilot, flight engineer or navigator assigned to the flight.

To me, it seems like this would be crucial information for the PIC to know, if their flight engineer (for example) was armed; but on the flip-side of this, the engineer might want to keep that to himself if he's with a crew he hasn't flown with before.

Is there a guideline on whether an FFDO should inform the crew that he's armed?


texts: Problem with right crosswind landing but not left

texts:
The prevailing winds where I'm training are almost always straight down the runway or from the left. I have no problem landing on (and staying on) centerline in either case.

However, when the crosswind is from the right, I tend to land on the centerline and then skip leftward.

I thought it was just me being inconsistent about my crosswind correction. However, during a recent lesson with wind 090, I was nailing every landing on 18, but when tower turned the airport around, I botched every landing on 36, so that seems to rule out coincidentally having a bad day every time there happens to be a right crosswind.

My CFI can't explain why I'm only having a problem with one side, much less how to fix it, and seems to be blowing it off since (now that the winds are back to normal) the problem has "gone away" again, but I'm not satisfied with that.

What could be causing this, and how do I practice for right crosswinds specifically when they are relatively rare here?


texts: Does the pilot in command always sit on the left seat?

texts:
Are there any rules (i.e. airline-specific) or regulations (laws) that state that the pilot in command (PIC) must sit on the left seat in commercial airliners?

This question specifically asks for rules concerning the PIC who is not neccessarily the highest ranking crew member (as I think that a check captain may sit in the right seat when checking a captain).


texts: I have heard of transonic speed and it is between supersonic and not supersonic. What is it and why does it happen to aircraft and how does it produce a lot of drag. How do you prevent it from happening?


texts: How do I use the takeoff and landing distance charts in the C172 POH?

texts: Can anyone explain how to calculate takeoff and landing distances using the chart for C172s, and please give me an example?


texts: How many radio transmissions per hour occur on a given frequency over Europe and North Atlantic?

texts:
For one of our research projects, we want to simulate a north atlantic flight from Frankfurt, Germany to the U.S.. To make it realistic, we are also simulating air traffic control - both instructions and clearances for the flight to be simulated as well as for all other flights on the same frequency. Now we were wondering, how "dense" is voice radio chatter over Europe (mainly Maastrict UAC and Scottish UAC) and over the North Atlantic (with CPDLC - Controller Pilot Data Link Communication in use)? In other words, how many transmissions per hour do pilots listen to in the given regions (approximately and in average)?

Please note, this question is not only about radio transmissions regarding the own flight, but transmissions from all flights on a given frequency that pilots listen to.

While this likely depends heavily on day and time, let's consider a typical weekday, departing Frankfurt around 10am local, so a time frame 1000Z - 1400Z for the above named regions would be of interest.

Can anyone, potentially a pilot regularly flying such a route, give some estimates?


texts: Does a failure to respond to FAA questions on ME disqualify for sport pilot?

texts: I had submitted a medical evaluation to pursue a private pilot certification. The FAA had requested further evaluation by specialists. I didn't respond to their questions. Does this disqualify me for a sport pilot license?


texts: How can I tell if an aircraft is equipped with fly-by-wire or with a FADEC?

texts:
Can anyone help me with a link or advice on how I can identify whether an aircraft is fly-by-wire (FBW)?

I understood the function of FBW, however if I want to know if a SA227 or smaller type of aircraft has FBW, I am not sure how to identify it? Is there a link or a way to exactly say which type of aircraft have FWB and which don't?

The same applies for FADEC as well.


texts: What purpose does a control area really serve related to managing air traffic flow?

texts: I can understand that we have control zones at busy airports to streamline the flow of landing and departing traffic. But in Control areas of many airports i have seen that routes go straight through the control area upto control zone. I mean no noticeable change occurs in route geometry. I can't understand what purpose are these control areas serving the air traffic services personnel? In other words, are'nt control zones alone enough to streamline landing and departing traffic at any airport? If not, why not? I am really confused about this.


texts: How can I find the optimum chord wing length for this wing?

texts:
This Aviation SE forum looks the perfect place to ask this question: people here usually make maths the root of most solutions and I think this may solve my aerodynamic optimization problem!

I am having a very hard time optimizing the wing size of my rc plane. I already went to the excelent RC GROUPS community but, despite the generous help of many people, this subject got a little more confusing and personal opinions (practical experience) are conflicting.

My question is this: I already have an rc plane (with tail, fuselage...) and I want to optimize the wing size in order to get efficiency and the longer flight time. I already built dozens of rc planes but this time I want to make this one the most efficient as possible.

IMHO to get longer flight time I need to consume the least amount of energy from my lipo battery as possible - so I need to keep my brushless motor running in the slowest RPM possible, consuming less Amps. Having said that, my total plane weight (not considering the wing, of course) is around 300g (summed weight of ESC, servos, 1000kv motor, 11 inch prop, fuselage, tail, receiver and battery). The weight is fixed, 300g. My wingspan is also fixed, 90cm. I cant have a wing longer than that. The wing shape is rectangular (I know elipses would be the better shape but let's fix the wing shape to simplify this discussion).

If everthing is "fixed" so what is the variable? Well, I want to find the optimum chord wing length for this plane which is gonna bring me the highest flight duration.

I am using the CLARK Y airfoil but you can assume any other one you want. I wouldnt like to discuss airfoil, I would like to discuss the size of the chord and how to optimize it.

My experience and lots of study into this subject says that high aspect ratio wing are usually more efficient than low AR. My wingspan is fixed and all other variables are fixed (to make this discussion more specific) except chord.

So my dear friends, I am struggling a lot to find the optimium chord to get the best flight duration. It looks easy but I am almost 2 months trying to get this answer from many different sources and I still cant find a good solution.

PS: I know I could optimize many of my other fixed parameters, but to avoid having this question marked as too broad/global/generic, I really would like to only optimize the wing chord.

PS (2): the plane that I want to optimize the chord is in the image below. The wing that I show on the picture already provides good flight time (around 22 minutes) but I would like to optimize it in order to get better flight time.


texts: Why does a sport certificate have no distance restriction while recreational does?

texts: A recreational pilot certificate only allows flights within 50 miles of home airport. A sport certificate has no distance limits even though it's easier to get - no medical certificate, less flying time and less instruction. What's the reason?


texts: Which manuals should I study before flying to France, Portugal and Switzerland?

texts: I am from Brazil. My crew and I will fly to France, Portugal and Switzerland. I am accustomed to flying to the USA, but it will be my first time to Europe, and I am studying the differences. Which documents and manuals do you recommend that I study and read? (Note: I want names not resource location)


texts:
I fly in/out of a small international airport occasionally, the runways are quite long. It is not unusual to land half-way or even three-quarters down the runway.

When doing this, pilots request long landings from ATC. I once did not request a long landing and did anyway and got chewed out a bit from ATC.

My question is:

Is it mandatory to request a long landing or is it more of a courtesy? Where is this information documentated?


texts:
I installed an app some months ago, which gives a push message when an aircraft squawks 7700. The first time it happened, I thought the plane was about to crash, but fortunately nothing happened.

However, within the last months, I got a lot of notifications, maybe a few a week or so. I'm wondering, why there are so many emergency alerts?

I've read about possible reasons for 7700 squawks and they seem to be manifold. Isn't the purpose of an emergency call to be used only in really critical scenarios? How is an aircraft going down to be differentiated from one carrying a sick passenger? Are there any plans in the industry to change the current system?


texts: What was in the noses of airliners before the weather radar?

texts:
At the time of the first Lockheed Constellations, airliners fitted with a weather radar were not common, and the navigator was not placed in the airplane nose. Thus, the nose seems to be mostly dead space.

Was the nose dead space with no useful equipment in it, or was it used for equipment I don't know about?


texts: Can a Diesel Aircraft engine be run on Car Diesel?

texts: What are the operational differences between normal diesel fuel used in cars and the Jet-A diesel type fuel used for some prop aircraft such as the Diamond DA62? I know that aircraft use Jet-A fuel, but could an airplane be run on car diesel?


texts: What is the difference between ICAO and non-ICAO flight address?

texts:
In document 260B, "Minimum operational performance standards for 1090Mhz Extended Squitter", on page 47 of the pdf, in the DF18 format they have mentioned for a particular CF(code format), "non-ICAO flight address".

So I wanted to know what the difference was between ICAO and non-ICAO flight address?


texts: Where can I find information on the DC-9's turn radius in flight?

texts: Does anyone know where I can find information on a DC-9-30's turn radius at various altitudes and airspeeds?  I've tried Googling it, but all I've found is information about its turn radius while taxiing.


texts:
Most large aircraft and some fighters have blunt, rounded nose cone. OTOH many fighters (that don't use the nose for air intake) and notably the two supersonic airliners (Concorde, TU-144) have the sharp tip for a nose cone.

What is the aerodynamic justification for that? What advantages and disadvantages does the "blunt" nose cone provide - or why don't all airplanes have the sharp spike nose cone (which "feels" like the obviously optimal aerodynamic choice - obviously that "feel" is somehow flawed?)


texts: What precautions are taken to avoid bird strikes?

texts:
According to this Wikipedia page on bird strike,

  The International Civil Aviation Organization (ICAO) reported 65,139
  bird strikes for 2011-14, and the Federal Aviation Authority counted
  177,269 wildlife strike reports on civil aircraft between 1990 and
  2015, growing 38% in 7 years from 2009 to 2015. Birds accounted for
  97%.

What precautions are taken so that birds are not killed by aircraft?
Is the pilot held responsible or does the pilot pay some penalty in case innocent animals are killed?
Are there any planes which have been designed specifically focusing on bird safety (or have there been any efforts in designing planes focused on bird safety)?
Where can I get reports on the number of bird strikes per year on an international level?

Note: This question does not concern the damages the airline suffers from bird strikes.

Update In Addition To Other Answers

Why jet engines are NEVER protected in the front?!


texts: Why did most airliners have black noses in the 60's and 70's?


texts: How can business jets use slot coordinated airports?

texts:
Many capacity-limited airports in Europe are so-called coordinated airports, meaning an airline must have a slot allocated to land at this airport. In Germany for example, these are FRA, DUS, HAM, MUC, STR, TXL and SXF. Often times, these airports are also used by general aviation aircraft, i.e. business jets, ambulance flights, government flights, etc.

Do airports "reserve" a given number of slots for such flights? Or are those flights exempted from the slot system?

I'm mostly interested in European regulations.


texts: Is the A320 family allowed to take off with the flaps retracted?

texts:
Is it legal for the A320 family (A318, A319, A320 and A321) to take off without flaps?

An answer to this question states that the A300 can take off without flaps. On the other hand, the 737 family of aircraft is not approved for a no-flap takeoff. (Under the right circumstances, you might survive one, but the margins for losing an engine would be unacceptable, so no data is published for such an operation.)


texts: With the on going grounding of 737 Max, if some airlines want to change their 737 Max to 737 NG what modification is needed? The main change would be the engine and control system. Any other change is needed in order for the plane to be re-certified for flight?


texts: Do jet aircraft have an emergency propeller?

texts:
I once heard, or misheard, this:

  There is an emergency propeller that comes down in an emergency of jet-engine aircraft. It is behind the main landing gears.

Is this true or a story somebody made up?


texts: Are runways booked by airlines to land their planes?

texts:
Suppose Indigo lands at Indira Gandhi international airport and the arrival is schedule at 5:30 a.m. Is the runway to land on fixed by the airline.

If not please explain reason behind not to schedule the runway on which the flights will land.


texts: Instrument approach DME VS instrument approch ILS DME

texts:
what is the diffrence of Instrument Approach DME and Instrument Approach ILS DME?
Is it same as LOC DME APCH and ILS DME APCH?


texts: Are there any unmanned variants of Solar Impulse?

texts: Solar Impulse proved to be capable of flying day and night without a single drop of fuel while carrying a pilot. Wouldn't it be easier to design an unmanned solar powered aircraft? Are there any? What about helicopters? Are they more difficult to make? What about automated landing at night time? I suppose there should be a lot of people interested in fuel-free aircraft, but why the only one I've heard of is Solar Impulse?


texts: Where is the fuel vent on a Piper Archer TX?

texts: I realized I haven't really noticed where the fuel vent is for the 2016 Piper Archer TX that I've flown, but I assume the fuel is vented from the fuel cap. Is that correct?


texts: What exactly are these unusual flight code names that require ATC priority?

texts:
(Related to this question)

The FAA's ATC Orders section 2-1-4 lists a number of different flight types that should get priority handling when possible. The obvious candidates are all mentioned: emergency services, VIP flights, search and rescue etc. But these less obvious ones are listed too, what exactly are they?

NIGHT WATCH aircraft
Aircraft using code name FLYNET
Aircraft using code name "Garden Plot"
Special Air Mission / SCOOT flights
OPEN SKIES Treaty flights


texts: Beside payload size, what precise factors are considered to choose the fuselages shape?

texts:
I am currently reading this very interesting book, which explains -I guess- most of the things you need to know in order to design aircraft.
Yet it is not clear to me besides the payload size what other factors are precisely used in order to determine the exact shape and size of the fuselage. I know that aerodynamics are considered, but that's very broad...

I read that the conic lofting method is usually used to determine the exact shape of the fuselage. But I would need some more explanation to get a better understanding of how this is determined.
In other words: I know my wing size, airfoil, payload size and would like to design the fuselage. How should I proceed?

Thanks

EDIT: Feel free to share the pragmatic approach

What bothers me is that I ended up finding a webpage with some interesting guidelines, but contains many constant values I have no I idea where they cone from: http://www.barnardmicrosystems.com/UAV/uav_design/guidelines.html

eg of such values: wingspan: 1.041, 0.382; step 3 length: 1.775


texts: How does a plane land without any radio connections?

texts:
It has been reported today that the German government plane "Konrad Adenauer", operated by the Luftwaffe, had a total loss of radio connection and diverted to Köln.

That made me think the following:

It was extremely fortunate that the problem did not occur somewhere over the Atlantic in the middle of the night.
How on Earth did they communicate their intend to land to the airport?

So, assuming it was indeed a complete loss of radio communications, how does a large plane like this indicate it has to land on an airport were it is not scheduled to land? Has that necessarily involved some jetfighters that communicate 'manually' (literally)? Is there an established protocol, e.g., a specific flight pattern?

1 http://www.spiegel.de/politik/deutschland/angela-merkel-verpasst-g20-start-flugabbruch-wegen-komplett-ausfall-des-funksystems-a-1241166.html


texts: Is the MTOW determined by the wheel maximum supported weight?

texts:
I was on a LATAM flight a couple days ago, and decided to have a read through their VAMOS magazine. As a lot of airlines do, they had a couple of pages on their fleet, and also a double spread on one specific plane.

This plane was the 777, which was a little bit surprising as they are about to get rid of those I think. Anyway, it had all the usual facts and figures, and also a couple of highlights about the plane.

I managed to find a web copy of the magazine, and the picture is below:

https://issuu.com/spafax/docs/vamos_latam_junio_2017_web

One of these highlights is the wheels, and it says (roughly translated):

  Each of the wheels is capable of supporting a maximum of 29,294 kg.

My first reaction was "That's pretty impressive!", then "I wonder how much above the MTOW that is?" The MTOW is specified at the side there: 351,530 kg, which correspondes to the 777-300ER.

So 29,294 x 6 x 2 = 351,528

Oh. That's under the MTOW. I wonder if there's some rounding off here:

So 351,530 / 2 / 6 = 29,294.166 - yes there is.

I was surprised that the maximum each tyre/wheel could take summed up to the MTOW, as I thought that they would experience larger forces on landing. Also, what would happen if a tyre blew?

So, does the maximum load for a tyre/wheel have anything to do with the MTOW? Or is this just marketing guys jumping the gun?

I have seen this question How is Maximum Take Off Weight determined? and that says that the manufacturers determine it, and it is based on the required payload of the aircraft and the design configuration, which doesn't really answer this question.

Edit with extra info mentioned in comments:

When stationary, the wheels will have a total force on them of 351,530 kgs, which according to this magazine is their max. When landing, the wheel like have to bear a weight of 251,290 kgs, plus the force of the landing. In my mind, the extra force of the landing would push the total above the MTOW, but this is just in my mind so I'm probably wrong :P


texts: Does EASA allow using a portable GPS for RNAV capability?

texts:
Assume an older IFR-certified aircraft with the classical equipment, that is two VOR/ILS receivers with plain CDIs, ADF and DME, but no GPS. It can be flown IFR, but many routes can't be used, because they use fixes that can't be found with this simple equipment.

If a suitable portable (that is, not built in nor connected to the aircraft systems) GPS unit is available in cockpit, and has appropriate aviation maps loaded, it it allowed to plan or accept an RNAV route that can only be flown using the GPS? What features and certifications does the GPS unit need to be usable this way?

Note that I am not thinking about any RNP procedure nor a RNAV approach (the ILS is there for approach in IMC), just normal en-route navigation over fixes defined by coordinates only. That way, the GPS is not critical—if it fails, I can always request vectors or rerouting over a navaid.

(If it differs over the world, I am most interested in European situation)


texts: I've heard that some airports don't have an ATC tower and nobody monitors the landings. Can someone tell me how those planes can land/takeoff safely without incidents occurring? I understand the fact that the airports without an ATC tower are small airports but wouldn't there be factors like weather which can cause accidents? So can someone please tell me how those planes can operate safely without ATC?


texts: When approaching stall, why does the center of pressure move back?

texts:
In an answer to a previous question, Peter Kämpf stated:

  Before the lift coefficient of a stalling airplane peaks, the flow over part of the wing will start to separate. Ideally it will do so near the trailing edge of the wing root, and the separation will slowly progress forward and outward as angle of attack increases. This separation will shift the local center of pressure back, such that the aircraft will experience an increasing nose-down moment as it approaches stall.

If separation starts at the back and progresses forward it seems to me that center of pressure ought to move forward. Why does it move back?


texts: What makes intentional low or missed approaches legal?

texts:
A common procedure in flight training is the low approach: simulating a landing, but without actually making contact with the ground before powering up and either going around in the traffic pattern or executing a missed approach procedure, sometimes after flying all the way down to an approach's minimums.
In this situation, a pilot flies very close to the ground - one suggested crosswind training procedure suggests flying along the runway low enough that "[i]t's OK if the wheels inadvertently touch down during the exercise."
Contrast this to other operations, including a simulated engine-out procedure away from an airfield. These are governed by FAR 91.119:

Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes:
(a) Anywhere. An altitude allowing, if a power unit fails, an emergency landing without undue hazard to persons or property on the surface.
(b) Over congested areas. Over any congested area of a city, town, or settlement, or over any open air assembly of persons, an altitude of 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet of the aircraft.
(c) Over other than congested areas. An altitude of 500 feet above the surface, except over open water or sparsely populated areas. In those cases, the aircraft may not be operated closer than 500 feet to any person, vessel, vehicle, or structure.

Training for missed approaches and going around are important for basic skills, and they are performed very frequently. However, the regulations make no exception for training. For a maneuver where a pilot descends below 500 feet AGL without intending to land, is there legal guidance that makes this OK near a runway, or is it an unwritten exception?


texts: Is airfoil thickness proportional to drag coefficient?

texts:
Does increase in the thickness of a camber airfoil mean more drag will be produced?
Why do slow flying planes have thick airfoils when it will just slow them down even more?


texts: Are exoskeleton wings technically possible?

texts:
While there have been a robot simulating a bird, could be there also an exoskeleton wing system for a human?

Main design considerations:

a) only human powered

b) using an additional, or exclusive source of power

I consider b) is more trivial because it's near to more or less attaching a human to a big bionic bird similar to mentioned above.

So we concentrate here on a).


texts: How does a synchro resolver converter work?

texts: There are Synchro converters or transducers used on aircraft to measure angle of attack using 3 sinusoidal inputs. I could not understand where  these 3 inputs come from and what angle information is generated by the synchro converter on the basis of the input signals?


texts: Pitch control of tailless aircraft/flying wings with very wide elevons

texts:
I'm writing a simulation of a flying wing and I need clarification on some of its behavior.
Specifically, the simulation suggests to me that a flying wing (or any tailless aircraft) with two single elevons along the whole of the two trailing edges is not controllable. If the elevons are deflected to pitch up, for example, it generates negative lift over both wings and the torque (assuming CoG is ahead of CoL) pitches the aircraft up. But this rapidly increases AoA and therefore lift and positive torque, pitching the aircraft back down until it stabilizes at Cl = 0 (steady state AoA depending on elevon deflection) because Cl = 0 is the steady state where no torque exists. However, it also generates no lift and the aircraft naturally crashes.
This result makes sense to me mathematically, but I struggle to observe this in real aircraft.
In a conventional aircraft the elevator is much farther back than the main wing and can balance the torque at a positive sum of the lift vectors. On a tailless delta aircraft with split elevons, the set of elevons towards the wing root have a CoL different from the elevons near the tips, which would allow small effective Cl according to the logic above. But this seems barely controllable to me and only reliable at high speed to compensate for the abysmal Cl.
Am I making a mistake? Is this really how it works?


texts: How can one change the wingtip geometry to enhance the wingtip vortices?

texts:
I'm doing some research on enhancing wingtip vortices as part of my Honours project. After spending a fair bit of time in the literature and on this forum I have some models which should kick-start my simulations. Because this is such a under-researched field (understandably) I wanted to mine the wisdom of those here: What design elements for a wingtip geometry would be conducive to creating a strong wingtip vortex?
The context is that I am studying how to enhance the efficiency of autonomous formation flight, using one drone as the 'tug-boat' for the other trailing drone. The leading drone would be outfitted with vortex-enhancing wingtips in order to increase the upwash experienced by the trailing drone. The overall purpose is to increase the range of the secondary drone at the expense of the first, in situations like scientific aircraft stationed in Hobart anf flying round-trip to Antarctica.
So far I have identified the Aspect Ratio, Lift Coefficient and Oswald Factor as parameters I'll need to change, based simply off the induced drag equation $C_{d_i} = \frac{C_L^2}{\pi*AR*e}$. This has given rise to potential solutions like using vortex generators on the wing surface to enhance lift while removing the winglet to allow the flow to curl around the tip, pitching the winglet up to increase its local angle of attack (effectively the same principle), and using a wingtip fence that runs from the leading edge to half the chord length and stops there, creating a high-pressure difference and then allowing the vortex to develop rapidly.
I'm aware I may have fundamental issues with this theory but also that I don't know what I don't know. If this won't work physically, then an explanation as to what I should be focusing on to create greater upwash outboard of the trailing edge of the leading wing would be much appreciated.


texts: Why didn't early jetliners use turbofans?

texts:
For subsonic operation, high-bypass turbofans seem to have essentially only advantages for efficiency, noise and takeoff thrust, at least until they reach the size where ground clearance or LP/fan speed mismatch become major issues. Yet early jetliners first used turbojets then only very low-bypass turbofans, despite the existence of turboprops meaning that using gas turbines for indirect propulsion was evidently understood.

Did they not fully realise the potential benefits at the time/thought they wouldn't work well, or was it just very difficult to build a jet with useful excess turbine power (to drive the fan) at the time?


texts: What difference is there between stabilizers and stabilators concerning longitudinal stability?

texts:
It is known how stabilizers affect the longitudinal stability of an airplane.

What about longitudinal stability in airplanes using stabilators (all-flying tails) or trimmable stabilizers?

Is it to be expected that certain combinations of angles of attack of the main wing and stabilators or trimmable stabilizers should lead to longitudinal instabilities?


texts: What repairs or modifications can be done without approval/certification?

texts:
I realize that this is likely to depend on jurisdiction (EASA or FAA would interest me the most in that case), but is there any common-sense kind of line that you don't cross until you've at least checked that it's okay?

I mean it's obviously okay to put checklists in a side-pocket, and it's obviously not okay to replace the avionics. Can I replace the PTT button on the yoke? Or if I don't touch the wiring and simply add some plastic on top give it a better feel?


texts: Can simultaneous departures be authorized from converging airports?

texts:
I am an ATC'r stationed overseas where we service two military airfields. The runways are 3 miles apart but converge. Our current regulations require aircraft from one airfield to delay in takeoff position while another aircraft is released or cleared for an approach to the other airfield, in order to protect from the missed approach point or departure route. However, our SIDS are designed to turn aircraft 45 degrees away from the other converging airport, but we are still required to wait.
We are in class G airspace with one airport 24/06 and the other, just south about 3.8 miles, on rwy 29/11. 90% of the time Rwys 24/29 are in use. The closest point of divergence, I'll have to double check for the exact distance however, the 24 departure SID is an immediate right turn off departure end, diverging at least 45 degrees from the missed approach or even departure of the southern airport in contention. Current rules require releases to be held if one or other other airports is departing aircraft however, it seems like the flight path deconflicts initially, making this unnecessary. I'll double check the distance, but our airspace isn't a factor. It's simply cutoff procedures that seem as a fail safe way of preventing an issue should the pilots heavily deviate from the SID (essentially flying rwy heading off 24) but very restrictive during departure phases.
Is there ANY way around this? Is it legal to clear both aircraft for departure with a SIDs that deconflict by 45 degrees from seperate airfields?


texts: Does the A320's FMC automatically adjust the rate of descent on a non-precision approach? Like a back course approach for example if the distance to altitude is (or can be) programmed in?


texts: What are typical airspeeds and lift coefficients for UAVs at different flight stages?

texts:
I've been trying (unsuccessfully) to figure out the relationship between airspeed of a fixed wing UAV at different flight stages. What I mean is, I would like to know the order of airspeeds from largest to smallest that would be expected for an aircraft (in particular an UAV with say 5m wingspan) to have during climb, cruise and descent. For example, the answer I'm looking for is something like: from largest to smallest, airspeed is expected to be ordered like this -> cruise>climb>descent (this would be my guess by the way).

Also I know that lift coefficient varies with angle of attack, airspeed and air density, but is it possible to make such a qualitative analysis to find an expected ordering like this for different flight stages? Looking only at the relationship between lift coefficient and airspeed, according to my previous guess, I would expect the lift coefficient to be smaller during cruise and larger during climb and descent. Is this correct?


texts: Where can I find an image of the Thales FMS220 RMS page?

texts: I'm looking for photo/color image showing Thales FMS220 RMS (Radio Management System) page. Also COMMUNICATION and XPDR pages are highly welcome.


texts: Linking equivalent airspeed with waypoints, altitude, time and speed

texts:
Say I want to find out EAS and I'm given a time that a pilot will reach a waypoint that is "X" Nautical Miles away, an altitude & I'm also given a ground speed that is increased by a tailwind. Is it possible to derive equivalent airspeed from these factors.

My current state of research is as follows:
I know the traditional EAS equation is useless in this case as I dont know the air density and other equations I've looked at require the Mach number which I also can't obtain. Basically all the EAS equations I've found require a density or the Mach number and I'm not sure how to proceed.


texts: If a passenger steps in for the crew, are they eligible for a reward as in maritime law?

texts:
Purely hypothetical question on aviation law.

In maritime salvage if your craft rescues/tows/supplies crew to a stricken vessel then you can claim a reward based on the value of the craft and cargo.

Let's assume that you are flying off somewhere warm for a few weeks in a commercial airliner and hear the call "Is there a pilot on board"... and let's all be honest every pilot has fantasised about it.

If you manage to take control of the aircraft and land it safely, does salvage law apply similar to maritime salvage laws? I cannot find anything online that covers it but it must have happened at some point in history.


texts: Why does the DC-9 have engines that are angled slightly upwards?

texts:
As per subject, I see that the above mentioned aircraft and some others that have engines mounted on the rear of the fuselage, have the engine intakes tilted slightly upwards. Why has this solution been implemented?

Wouldn't it be better having them parallel to ground?

If the airflow of the exhaust is directed slightly towards the ground would't it affect the plane causing it to push the nose downwards?


texts: Can a commercial pilot get paid by friend?

texts:
'm a little bit headache about charge issue with commercial pilot certificate .hope someone help me figure out.

IF my friend approaches to me first and ask for a flight to somewhere using my airplane and I get paid for this flight,am I holding out?If I am,how can I do that legally?How about using his/her airplane?
According to 119.1(e),can I hold out for those flights and get paid(Ferry,banner towing etc.)and get paid？


texts: Why am I getting a low L/D of 4.3 for this supercritical airfoil in Autodesk CFD?

texts:
I am a high school student learning to analyze aircraft models in Autodesk CFD for the first time. My current project is analyzing a supercritical airfoil on Autodesk CFD (that was designed in Autodesk Fusion360).
Can I get help with the following : I researched several turbulence models in Autodesk and I chose the SST k omega turbulence model, with a 250 m/s inlet velocity, 0 gauge pressure , unknown outlet and a compressible flow.
I am getting a lift to drag ratio of approximately 4.3. I think the lift to drag ratio is too low. I am suspecting the analysis conditions are to blame. Are these the correct input parameters? Am I missing anything else?
Here is a screenshot of the analysis: I ran the airfoil analysis at angle of attack of 5°.


texts: What are the implications of building a private airfield in the United States?

texts:
I've always wondered what it would take to build my own airfield.  I live close enough to an area where this would likely be possible (50 NM radius around Front Royal, Virginia, obviously outside the DC SFRA) and there are a number of private strips in the valleys adjoining mountain range I live near:

Here are the parameters I would consider, which would allow operation of one or more small general aviation aircraft:

Runway width - 50-75 feet
Runway length - 2200-2500 feet.
Runway surface - grass
Buildings - Space for a hangar (converted barn?) and a moderately sized house.

Answered Questions:

What are the legal implications in the United States?  Do you have to get permission from the government to do this?  Is this airspace dependent?  Answered in linked post and this post.
What about permission from neighbors?  I'm going to guess this will be harder to answer, since it likely depends on jurisdiction.  However, if anyone has done this, perhaps they can share their experience in this area.  Somewhat answered in revised post.  Still interested in additional experiences.

Outstanding Questions:

What would it cost to maintain this installation, above and beyond the cost of maintaining any piece of property of this size?  What's included in these costs?
Are you required to pay to have an airfield listed on charts?
Do the parameters I've listed seem reasonable for the requirements I've mentioned?


texts:
I wish to load test a model glider wing.

The standard static load test methodology using sandbags on the upturned wing would be difficult as the chord of the wing is small - it will be difficult to securely attach the loads required.

Are there any other methods commonly in use to do this kind of test that might be easier?


texts: How to convert an EASA CPL(H) to FAA CPL Rotorcraft With a Helicopter Class Rating?

texts:
I just finished my CPL(H) license and was just wondering if it is difficult to convert your license to an FAA (or TCCA) license.

Do you have to do additional exams or check rides?

It's hard to find a step by step guide to do this, or do you recommend to contact a training organization in the US or Canada to perform the conversion?


texts: Can anyone explain the reflex wings used in powered paragliding?

texts:
There are some paramotoring wings presumably designed for higher speeds. The method is to allow a portion of the wing near trailing edge to flutter in high speed, rendering it unaccountable for development of lift, but still accountable for drag (in my opinion). I believe is called reflex because the trailing edge will flex up in high speed.

The speed gain is minimal though. These wings fly at around 40km/h with stall at 24km/h and the reflex promises 60km/h, while the same wing trimmed non-reflex achieves 55km/h.

If there is anyone with piloting experience on those wings, please explain the reflex from your perspective.


texts: How does wing bending relief of an a340 compared to an a330 allow it to carry 30t more fuel in a center section of nearly identical wings?

texts:
From this question this reference in ymb1's answer states that the a340 and a330 have nearly identical wings.

Because of bending relief from the weight of its outboard engines, the bending moment of a four-engined aircraft is substantially lower than it is for a twin at the same maximum take-off weight. For the same fuselage weight, therefore, a twin needs a stronger, heavier wing than a quad.
It follows that, for the same wing, the payload carried in the fuselage must be less for a twin than a four, which is exactly what has happened with the A330/A340: the latter carries about 20% more payload. This translates to about 30t of extra fuel, giving the A340 its long-range capability and requiring the addition of a centre-fuselage undercarriage leg. Design strength required was "only 1% higher than the A330", says Jeff Jupp, BAe chief engineer, Airbus.

(Original: A330, A340)
The reference states that bending relief by having four engines instead of two is the reason 30t more fuel can be carried in a wing center tank.
How can moving 4t (per engine) outboard 10m create enough bending relief to add 30t in the center of the wing?


texts: What's the breakdown of total development cost for the various components of an aircraft?

texts: Can someone please explain citing an example Aircraft an approximate breakdown  of the cost incurred in developing each part of the aircraft( fuselage, engine choices) and other things like certification that allow it to be sold to the public. Preferably an example of a plane with a clean sheet design like the Concorde which was nothing like other planes of the time.


texts: How are parallel runways named if there are more than 2 or 3?

texts:
I know that it's very common for runways to have a parallel neighbor, and they're normally called left and right. I have also seen some runways called "center" if there are three parallel runways.

What would happen if there were more than that? Is this even possible?


texts: How do I calculate the landing weight in this situation?

texts:
Empty weight 538kg
Pilot and passengers are 150kg with full fuel tanks

If we use 2 US gallons for taxi and 10 US gallons for the trip, what will be our landing weight?

Fuel Capacity

Total Fuel Quantity:  24.5 US gal. (93.0 liters)
Usable Fuel: 24.0 US gal. (91.0 liters)
Unusable Fuel: 0.5 US gal. (2.0 liters)


texts: What is the fluid released from the tail of this clipped Turkish airliner?

texts:
A Turkish A321 airliner was hit by an Asiana A330 on 13 May 2018 at Istanbul Airport. It seems a large amount of fluid was released from the damaged section. What is the fluid? There is no APU up there so only hydraulic fluid, am I right?

Some news: https://onemileatatime.boardingarea.com/2018/05/13/turkish-plane-tail-istanbul/


texts: What is the exact wing chord length and thickness for Boeing 747?

texts: I can't find this info anywhere and all they give me is the ratio. However, I need the exact/approximate values


texts: Can having an incorrect hair color on my FAA medical certificate get me in trouble?

texts:
I just got a new FAA medical certificate, and I accidentally put down that my hair color is blonde when in reality it is dark brown. Also, my hair is listed as brown on my pilot certificate.

I bleach my hair in the summer, which makes it blonde.

Would such a small detail cause any sort of trouble?


texts: Why don't light-up runway numbers similar to runway lights?

texts:
I know that some airports have lights on the runway that can be controlled with the mic transmit button. Additionally, during night flight, runway lights help the pilot determine where the runway is located on the ground.

However, the runway numbers/letters are always indicated on the end of the runway, but do not light up. Why aren't the runway numbers made to light up? I'd think that at busy airports, this would help pilots determine the correct runway at night (ex. in the case of a "left"/"right" runway for a busy airport).


texts: Does uncoordinated control affect stall speed?

texts: Does an uncoordinated turn increase stall speeds? When you do cross control for crosswind landings in GA aircraft like C172, should you be worried about higher stall speeds during flares?


texts: Is an Aileron Roll Easier Done Opposite The Rotation Of The Plane's Propeller?

texts:
We all know helicopters have tail rotors because they would spin out of control thanks to Newton's third law.

That got me thinking, would a single propeller plane have an easier time doing an Aileron roll opposite the rotation of the propeller? And do light aircraft require any special tricks like having one wing longer than the other or the ailerons being tilted in the rest position?

To be clear, I really don't know any more about aviation than the average person. The question just crossed my mind and I didn't find anything googling around.


texts: What is the reason for KSFO PRM approaches being decommissioned?

texts:
In the latest terminal procedures packet dated April 22nd all San Francisco PRM approaches have been deleted.  I haven't seen any notice from the FAA on the decommissioning and am curious what the reason is.  Is there any official documentation on the decommissioning?
Thanks


texts: Which type of fan is better for wind tunnel testing?

texts:
I would like to build a small wind tunnel to test a miniaturized wing/airplane. I have two options, using axial blower (picture 1) or using centrifugal blower (picture 2). The first will be the wind source for "pipe" tunnel while the second one will be connected to a ducting tunnel. The size and the power (cfm) will be provided as per requirement.

Then my question: which one is better of the two? Or, is any other better alternative?


texts: Are planes allowed to fly through a planned professional fireworks display?

texts:
I was watching 4th of July fireworks tonight, and I noticed a very low plane circling the fireworks display.

I'm wasn't sure of its altitude, but I would estimate around 1000 ft or no higher than 1500 ft.

I'm thinking, "that's pretty low around here", and "it would be cool to be in that plane, with that view."

The plane then turns sharper toward the fireworks, then flies right through the middle of it, as fireworks are going off around the plane.

The plane then circles around again and flies just above display this time.

Is this even allowed?

If not, how would this pilot be held accountable/caught?

If so, how is this safe?


texts: What are the dimensions of an NPT pipe for fuel systems?

texts:
I have a question about NPT (National Pipe Thread) tapered connectors that are used in fuel systems of several airplanes. Please take a look at this standard-wall one-side threaded nipple (3/4 pipe size, 2" long).

My questions are:

1) How do I decipher the specified pipe size? This one is 3/4, but 3/4 is not any of the dimensions.

2) Why would the unthreaded side have the diameter 1.050"? I want to connect it to a pipe with a 1.0" diameter (yellow color, on the right) as shown in the picture below but I am concerned about mismatch when I use a threadless compression coupler.


texts: Can I get a third-class medical if I have sleep apnea?

texts:
Some year-and-a-half ago my physician recommended that I take a sleep study. Some preliminary exam (overnight finger-carried monitor) indicated that a few times per night my oxygen level dips below 91% (and one time below 81%). He indicated that this might be caused by sleep apnea. I ignored that recommendation as my sleeping had improved and I didn't want to spend money and time on the full-blown sleep study. Six months after that I started my PPL training. As it was not an issue, I didn't even think about it when I got my 3rd Class med certificate.

My soon-to-be-ex wife had recently found my old correspondence with my doctor and, out of pure vindictiveness, denounced me to the FAA. I received a letter giving me 60 days for addressing this issue. Here are my questions:

Does anyone at this forum has a mild case of sleep apnea and is still flying (i.e. has a valid third class med)?
Is the dip in the oxygen intake an 'sure proof' of sleep apnea?
Are there any other types of SA than Obstructive SA that are not viewed as dangerous by the authorities (the regs specifically mention OSA)?
Is there any recommended treatment that may still make the med cert possible even if I have a mild case of SA?


texts: Definition of Critical Part in type certification process

texts:
first time here :)

I'm part of the team at Flytrex (flytrex.com) and we're working with the Aircraft Certification Office to certify one of the first UAS systems (drones) under new initiative to certify drones for commercial use.
We are currently at the stage that we need to define our system critical parts.

From what I understand, a Critical Part is defined as a single point of failure that will lead to a crash of the aircraft.

Since every component in our system includes redundancies, is it reasonable to claim that we don't have any Critical Part?

Some examples:

Single motor loss - the aircraft uses 6 motors and can sustain a single motor loss.
Multiple motor loss - an independent parachute system is deployed, taking the aircraft to the ground safely.
Flight controller loss - again, parachute will deploy.
Parachute system failure - the flight controller will bring the aircraft back to safe landing (abort mission).

I think we need a clearer understanding what is considered a critical part, and then try to define the right parts in our system.

Many thanks!


texts: What endorsements does a student pilot need to practice maneuvers solo with no limitations on distance from the airport?

texts:
A question regarding the purpose of 61.93(a) and the distance limitations on a student pilot solo'ing in the local practice area.
Scenario:
A CFI trains a student in accordance with 61.87. They endorse a student pilot with the endorsements required in 61.87(c)(1)(2) as well as 61.87(n). The student solo's out to the local practice area and performs several maneuvers, but while doing so, goes 30nm from the airport. They return back and land at their home airport.
Did the student pilot violate 61.93(a)(1)(i), which says

Conducting a solo cross-country flight, or any flight greater than 25
nautical miles from the airport from where the flight originated

If this would be a violation, what exact requirements are necessary to meet for the student to just perform maneuvers in a practice area without a distance limitation (i.e. 25nm)? 61.93(a)(1) just says, "must meet the requirements of this section".


texts: How can I get the ADS-B GNSS Antenna Offset and Position Offset?

texts:
I'm reading the FAA's Advisory Circular AC No:20-165 appendix 1 point 28, which talks about GNSS Antenna Offset and Position Offset.

How would I receive this information from an aircraft? Is it transmitted?


texts: Can I join the Navy after a corrective eye surgery and still be a Naval Aviator?

texts:
I currently do not pass the requirements for uncorrected distant visual acuity according to the Navy physical standards document. However, if I were to receive eye surgery to correct my vision before joining and then apply to OCS/Flight School, would I be cleared as Class 1 aviation personnel and be able to fly as a Naval Aviator? Thank you!

(Here's some of the information from the linked pdf)

Class I: Naval Aviators and Student Naval Aviators (SNA). Designated Naval aviators are
subdivided into three Medical Service Groups based upon the physical requirements of their
specific flight duty assignment

Medical Service Group 1: Aviators qualified for unlimited or unrestricted flight duties

Medical Service Group 2: Aviators restricted from shipboard aircrew duties (include
V/STOL) except helicopter

Medical Service Group 3: Aviators restricted to operating aircraft equipped with dual
controls and accompanied on all flights by a pilot or copilot of Medical Service Group 1 or 2,
qualified in the model of aircraft operated. A waiver to medical Service Group 3 includes pilot-incommand
(PIC) authority unless PIC authority is specifically restricted.

Service Group 1, 20/100 or better each eye uncorrected, corrected to 20/20 or better
each eye.
Service Group 2, 20/200 or better each eye uncorrected, corrected to 20/20 or better
each eye.
Service Group 3, 20/400 or better each eye uncorrected, corrected to 20/20 or better
each eye.

The first time distant visual acuity of less than 20/20 is noted a manifest refraction (not
cycloplegic) shall be performed recording the correction required for the aviator to see 20/20 in
each eye (all letters correct on the 20/20 line).


texts: I have an idea about how to resolve a conflict between the pilots and an automated flight control system. Does it make sense?

texts:
I am thinking about the 737-MAX crashes.  There is a similar question at Is it common for automated control systems to use non-redundant sensors?  There was an article in yesterday's Seattle Times In key step for potential late-November ungrounding of Boeing’s 737 MAX, FAA details minimum pilot training which references Why Boeing’s emergency directions may have failed to save 737 MAX.
My thinking is that if the pilots are applying a force to a control which is near the limit of the strength of a human being, then the control system ought to recognize that the pilot is fighting with it.  If the control system recognizes that the pilot is fighting with it, then it ought to assume that the pilot knows what he or she is doing, and let the pilot do what he or she wants to do.  There might be an indication along the lines of "Are you sure you know what you are doing?".
I order to recognize that the pilot with fighting with the system, I propose adding a strain gauge to the controls.  Normally, one should be able to fly the airplane with one hand.  If a pilot is using two hands to fly and is using large forces to do so, the strain gauge will detect that (technically, the pilot is stressing the control by applying a force, and the strain gauge is measuring the deformation of the parts the pilot is forcing), and that will tell the automatic system to "let go" and do what the pilot wants to do.
Does this sound like a good idea?  I am neither a pilot nor an aeronautical engineer.  However, I once worked as a computer programmer in a test lab and I wrote software to test strain guages.
Thank you


texts: Can we bring a rotorcraft like Ingenuity to an altitude of the same pressure as the one on Mars?

texts:
At Perseverance's and Ingenuity's location the atmospheric pressure is about 750 Pa (0.11 psi). On Earth, we find that pressure about 110,000 ft high. If we built a copy of Ingenuity, could we bring it up there or close to that altitude? Probably not, because of the Earth's higher gravity and its atmosphere's lower density, but how high could we fly it?
The highest vertical rotorcraft so far went to "only" 40,800 ft (12.4 km), this was a massive crewed helicopter.


texts: Can we use the mobile phone GPS at 36,000 ft?

texts: Is it possible to use the built-in GPS function via the smartphone at high altitude during flying as a flight crew ?


texts: Can commercial pilot get paid for introductory flights with their own customers?

texts:
Can a pilot with their commercial certificate look for their own customers, rent an airplane, and get paid to do introductory flights?

If yes, where in the FARs does it talk about it?


texts: Does the nose-up attitude of a jet make it more difficult to land than a turboprop?

texts: Due to the more acute nose down attitude of a turboprop on approach, does this make it less difficult to control compared to the relatively high nose up attitude of a jet?


texts: What is the meaning of "transition area" as used by the FAA? Has the meaning changed over time since the term was introduced?

texts:
What is the meaning of "transition area" as used by the FAA?  Does it currently have a specific meaning?  Does the FAA still use the term at all?  Has the meaning changed over time since the term was introduced?  Is it a term that ceased to have a specific official meaning after the September 1993 "alphabet" airspace reclassification?

Additional context:

FAR 71.71 reads--

  § 71.71 Class E airspace. Class E Airspace consists of:

  (c) The airspace areas listed as domestic airspace areas in subpart E
  of FAA Order 7400.11D (incorporated by reference, see § 71.1) which
  extend upward from 700 feet or more above the surface of the earth
  when designated in conjunction with an airport for which an approved
  instrument approach procedure has been prescribed, or from 1,200 feet
  or more above the surface of the earth for the purpose of
  transitioning to or from the terminal or en route environment.

Does this suggest that the term "transition area" is best reserved for areas of Class E airspace with a floor at 1200' AGL?

The term "transition area" does not appear in the FAA's "Airspace Designations and Reporting Points" document, current edition Order JO 7400.11D.

As airspace with a 1200' Class E floor has proliferated to cover most of the US, it seems to have become a common practice to use the term "transition area" specifically to refer to areas with a 700' Class E floor that are protecting instrument approaches. Is this really a correct practice?


texts: Could an aircraft have squashable wings that get thicker as it flies faster?

texts: As I understand, for high speed subsonic flight a thicker wing is more aerodynamic, and at low speed, a thin wing is preferable. Could aircraft which range in speed from 180 to 620 knots (most commercial airliners) have wings which can compress to be thicker during high speed flight? This would be controlled either by a mechanical system to change its shape or just by the oncoming wind pushing it into shape.


texts: Why did the first Boeing B17 test flight crash on takeoff?

texts:
Wikipedia says that the control surfaces were locked.

What does this mean, and if the control surfaces cannot be moved, how did the aircraft get into the air in the first place?


texts:
What are stick position stability and stick force stability?
What are the difference between them?
How will changing trim of an aircraft affect them?


texts: How to know if an airport has PAPI lights?

texts:
Is there any way to identify whether an airport has PAPI lights (2-light or 4 light system, doesn't matter)?

I am working on some map generation and using aerial images to identify PAPI lights for airports. I was wondering if there is any quicker way to identify visual whether PAPI lights exisit on airport runways.


texts: What should I consider when storing a light aircraft outdoors for several months?

texts:
I would like to store a Cessna outside for a period of time, close to six months. The temperature here will not exceed 30°C and will not go below 0°C.

With tie downs and a tarp, how long can I store a Cessna outside for in these conditions? Should I invest in a shed of some sort? I would prefer a specific period of time please.


texts: Which aerobatic manuvers should I restrict myself to if I wear glasses?

texts:
Are there aerobatic maneuvers which I should never attempt if I wear glasses? Or, is there a specific G-loading which is not recommended for pilots who wear glasses?

I'm not into competitive aerobatics. I will not pull 6~7Gs or perform violent maneuvers like snap turns. However I do like to flip the world around just for the fun of it.


texts: Does the large 6-pointed star on a sectional warn of dangerous radar facility?

texts:
I cannot find an explanation for this symbol on the chart legend.

Example: near BAB, Beale AFB, on the San Francisco Sectional Chart, does it warn of the dangerous radar facility?

Source: skyvector.com


texts:
I am looking for some help regarding decoding ARINC 429 data.
I have a CSV document that contains sequentially stored ARINC 429 labels.

My overall goal is to be able to scan for 4 specific labels and only decode those frames (data field, label field, and ssm field) and append them to the document.

Does ARINC 429 randomly come in different data formats (i.e. BCD, BNR, Discrete Bits, etc)?

Since I am looking for specific labels, is it okay to only have it set to decode BNR format or do I need to be able to identify and decode all the data formats?


texts: Can fighter jets set their lights to flash six times?

texts: So last night President Trump was in town at the Grand Rapids Airport in Michigan. I live about 5 miles away directly to the west of the airport. I noticed multiple high and fast flying jets (they were not on my Flightaware app). I would see them flashing 6 times quickly with about a 1-2 second pause in-between. It was very consistent. I had never seen 6 quick flashes from any jet ever. I'm hoping someone can verify which type of (I'm assuming fighter) jet can do that, and why?


texts: Can an aircraft be issued a standard airworthiness certificate after being operated under and experimental certificate?

texts:
14 CFR, §21.191 (b) states that experimental airworthiness certificates can be used when:

  Showing compliance with regulations. Conducting flight tests and other operations to show compliance with the airworthiness regulations including flights to show compliance for issuance of type and supplemental type certificates (...)

Can the aircraft that is used for such testing be converted back to a standard airworthiness certificate after testing is complete?

Example scenario: Manufacturer A is developing a new autopilot to be offered as an after-market modification (along with the necessary STC). The manufacturer purchases an aircraft with a standard airworthiness certificate, installs the prototype avionics hardware, obtains an experimental certificate, and performs the necessary testing. Once complete, he manufacturer would like to return the test aircraft back to the condition it was before obtaining the experimental certificate in order to sell it with a standard airworthiness certificate.

Is that possible? If so, what would the manufacturer need to do in order to demonstrate that the aircraft was not operated outside of the limits of the standard airworthiness certificate while under the experimental certification? What FAA documentation exists that would provide guidance on this?


texts: What are regulations for pyrotechnics on planes?

texts:
Being in love with both fireworks and flying this is a question that I wondered about for quite some time.
Especially when watching videos like this (which is from 2009 showing a stunt plane flying stunts during night with sparklers on the wings and some single shots) or this (a glider with essentially the same effects like the stunt plane from 2015) I wonder what safety regulations apply.

Most certainly I am not allowed to duct tape some rockets to my wing and light them off remotely mid flight but I haven't heard about a firework rating or something similar either.

What requirements do I have to accomplish to be allowed to fly with pyrotechnics (mainly fireworks) on my plane? This would include anything additional directly in my PPL, permission by local authorities, special safety measures on the plane, etc.
This question is mainly regarding the european room (namely Germany) but I am also looking forward towards answers about regulations from other regions.


texts: Why is the "Dutch" roll called so? When did this name enter common usage, and what is its origin? Please cite sources if possible!


texts: In light aircraft, non-instrument flight, apply (nearly) full aft elevator before beginning the takeoff roll or at some predetermined speed?

texts:
Consider a small, light, nose wheel tricycle aircraft, something along the lines of a C152 or similar, sitting at the end of the runway ready for takeoff, with no issues and with all pre-takeoff checks completed.

In general, what is the correct procedure for take-off with regards to the elevator and nose wheel?

One instructor I've flown with taught takeoff as apply nearly full aft (nose up) elevator before beginning the takeoff roll. After rotation occurs, accelerate further to and maintain best climb speed, limited by maximum flaps extended speed (which for the particular type I'm flying are identical). This approach has the obvious advantage of getting the nose wheel off the ground as soon as there is sufficient lift for that, and ensures that one can look straight ahead at the runway, not really having to worry about the instruments at all before rotation, but means you need to be careful to not apply too much aft elevator at the moment the nose wheel lifts off the ground (since you don't yet have sufficient speed to actually fly, and by rotating too quickly you'll end up with a tail strike on the runway).

Another instructor, in the exact same aircraft, advocated neutral elevator until around the maximum speed the nose wheel can take, then slight aft elevator to raise the nose wheel, and more aft elevator for lift-off only when approaching speed of best climb. This has the advantage of keeping you near the ground longer during the takeoff roll, but requires keeping pretty close tabs on the instruments (and possibly adjusting from airspeed to ground speed, because the nose wheel is concerned with ground speed which is likely less than the indicated airspeed because the airplane is facing a headwind component). To me, this seems more complex.

Obviously in both cases, after lift-off, the important number becomes the indicated airspeed (a proxy for which can be engine power and airplane pitch), which should be near the speed of best climb to gain altitude as quickly as possible. That's the easy part.

But while the wheels are still on the runway, why would one prefer one style of takeoff over the other? Are there any particular situations in which either is clearly superior to the other, or is it merely a matter of taste?


texts: Can a pilot use ILS when cleared for a visual approach?

texts: When cleared for a visual approach, do airline pilots still use the localiser/glideslope or GPS or even the autopilot, or is it strictly a "visual" approach?


texts: What is the maximum lateral deviation allowed on an RNAV route?

texts:
If an airliner (enroute via IFR rules) discovers a thunderstorm ahead, how much lateral deviation is allowed before a clearance from ATC needs to be obtained ?
Is the width of an RNAV corridor only for navigation errors or also for intended deviations ?