texts: Which is safer? The Piper Tomahawk or the Cessna 152?

texts:
I have booked my first flying lesson for 2 weeks time, in my first step to obtain a PPL or LAPL. I had done all of my research on the Cessna family, assuming that is what I would learn in. I was satisfied by the safety and glowing reviews by students and instructors alike.
Anyway, my local school has since told me that they don't have the 152 anymore, so I will be learning in a Piper Tomahawk. Some quick reading here states:

The PA38 accident rate ranged from 0.336 to 0.751 fatal stall/spin accidents per 100,000 flight hours, compared to 0.098 to 0.134 for the 150/152.

and

There was always a concern about the stall and spin characteristics of the Tomahawk. The old adage “be careful what you wish for” applies because an overwhelming majority of the PA38 survey respondents requested an aircraft that would stall with more authority than the 152. And they got it.
You’ll hear many people talk about the stall characteristics of the PA38 like they’re referring to a demon, but it should be remembered that this was essentially a design feature to teach better pilots. Unfortunately, this led to a higher than average stall/spin accident rate that earned the PA38 a less than admirable reputation quite quickly (thus the nickname Traumahawk and Terrorhawk).

This isn't as comforting. So taking into account engine reliability, stall issues, etc. - which aircraft really is safer?


texts: How many axes are used in weight and balance calculations?

texts: When doing weight and balance calculations on fixed wing aircraft is the transverse axis (wingtip to wingtip direction) used?  Or is only longitudinal axis considered?


texts: Should I log flying lessons from the start?

texts:
I've recently started taking flying lessons and was wondering if I should begin logging my flying hours immediately?

I'm aware there are minimum hours for each license certification, so I'm assuming I should be noting down my flight time right from the start but my instructor hasn't really said anything about it yet.


texts: How can drag induced by the landing gear be reduced?

texts: What are some of the methods used to reduce the drag caused by the landing gear for aircraft with non-retractable landing gear?


texts: What is typical cruise altitude in the Himalayas?

texts: An important tourist connection goes from Tribhuvan International Airport (VNKT) in Kathmandu, at 4,390 ft, to Tenzing-Hillary Airport (VNLK) in Lukla, at 9,334 ft. The mountains around Lukla quickly raise from south to north. Right around Lukla the ridges rise to about 15,000 ft, but the aircraft does not have to fly over these, since decent approach is only possible through the valley from the south and the ridges are somewhat lower further south. So does anybody know what is actual typical cruise altitude in that area?


texts:
I was having a conversation concerning airplanes and the calculated fuel. We were having a conversation about the Airbus A380. Based on this site:

http://www.modernairliners.com/airbus-a380/airbus-a380-specs/

It shows a capacity of 320,000 Litres. After some conversion (I am in the US)

320,000 Litres = 84,535 gallons

84,535 gallons = 710,000 lbs

Now that is based on water density. I've heard that jet fuel isn't exactly comparable to water? Is this true? I am trying to confirm because 700 thousand pounds of fuel sounds like a lot? Is there something I am missing? An average Olympic sized swimming pool carries about 660,430 gallons of water. How does this plane carry that much weight? And what would be the easiest way to explain this to a layman like myself?


texts: What do you call the portion of a tail-dragger takeoff when the tail is in the air?

texts: During a take-off roll out down the runway, in a tail-dragger airplane, what is the period of time called where the plane is level, with the main gear still on the runway, but the tail has come up off the ground and before you pull back on the stick to begin climb-out?


texts:
I live in Southern California and was surprised to learn today that a local company is operating very short-haul VFR flights as an alternative to car commuting.

https://www.floatshuttle.com/

I can understand operating out of small airports to keep costs down, but flying VFR for a service like this seems unusual to me. Is this legal?


texts: What should I do if I lose situational awareness while in the pattern?

texts:
Let's say that I'm doing some pattern work in my favorite little Cessna or Diamond at my favorite little non-towered airport. Everything is going just fine, I'm on the downwind leg...

Or, wait a minute, am I on the crosswind leg? Which runway are we using today? I just heard another plane on the radio that I can't see; what did she say, again? Is she behind me or are we on a collision course?

In short, I suddenly realize that I don't have a full picture of what's going on here.

What are my options here, and how should I choose between them?

Here are my ideas, from best-sounding to worst-sounding:

Just climb out of the pattern, then fly a safe distance away from the airport, descend, and fly back into the pattern. I assume that after starting the climb, a quick radio call wouldn't hurt: "Wobegon traffic, Skyhawk eight three four sierra tango, climbing out of the pattern and going west." (I've always heard that you should never descend or climb directly into the pattern, but I've never heard that you shouldn't climb out of the pattern.)
Keep flying, keep looking out the window, and talk fast on the radio: "Aircraft at Wobegon, where are you again? I'm not sure exactly where I am, do you have me in sight?" (I'd feel stupid saying this, but it's better to speak up and feel stupid than to stay quiet and be stupid.)
Keep flying, keep looking out the window, stay quiet, and just try to figure out what's going on.


texts: What is the cost per hour of a Gulfstream V?

texts: Could someone inform me about the exact operational costs of a flight hour for this specific type of aircraft?


texts: What was the decrease in approach speed of the KFIR over the Mirage 5 due to the canards?

texts: The Mirage III approached at 170 knots according to the Dassault. The Mirage NG and the KFIR C2 as well as the Swiss Mirage 5s added canards to the design, what was the decrease in approach speed due to these changes? I see improvements in low speed handling stated in some references, but does anyone have any references to the approach speeds of the modified aircraft?


texts: How can an airplane keep going forward if it has no thrust?

texts:
Every pilot is familiar with the basic model of aircraft forces:

If lift is greater than weight, the plane climbs, if less, descends.  If thrust is greater than drag, the plane accelerates, if less, decelerates.  In unaccelerated flight, all must be equal.

In an engine-out situation, there is no thrust, so if a constant glide ratio is to be maintained, I thought the plane must be pitched forward so the forward component of lift does the job thrust would normally do in cancelling drag.

However, in the Airplane Flying Handbook, 4-3, figure 4-2, it shows an example lift-drag diagram that shows $L/D_{max}$ ($= V_{BG}$) to be about $6°$ AoA.  Wouldn't that result in lift having a backwards component and slowing down the aircraft to the point of stall?

What am I missing here?


texts: Are there any reference values for Cl and Cd of a NACA 0012 airfoil to verify CFD simulations?

texts:
I am having trouble finding the established results of inviscid flow CL and Cd variation over NACA 0012 airfoil, for the transonic region. I need the data to verify the results I am getting through my CFD simulations. I have recently started learning CFD and the actual results would be really useful to me as they would clarify whether I am in the right direction or not.

Please suggest any site, research paper or book.


texts: What is the altitude record for the F/A-18 Hornet?

texts: Does anyone know how high (above MSL) the F/A-18 ever went? Its service ceiling is 50,000 ft, but when going up steeply, is it able to surpass 100,000 ft altitude?


texts: Is the B737NG AoA indicator a "normalized" indicator?

texts: Is the B737NG AoA indicator, when/if it exists, an indicator of "normalized" AoA, or does it indicate the actual AoA measured?


texts: Are there any aircraft with retractable vortex generators?

texts: From this answer, “Of course, these also add drag, even when the wing is not stalling, so they are only added where needed”.  Are there any aircraft that have vortex generators that are retractable so that if the flight computers determine that the wing is stalling, the vortex generators are automatically deployed without them causing drag all the time?


texts: Does the Flight Acquisition Unit on the Boeing 737 NG stream data?

texts:
I noticed on B737-800 entering the flight deck on the right side there is a port Data Loader and I think this is the Flight Acquisition Unit.
Is this port used exclusively for loading data to FMCs etc or it can also read data?
Does the aircraft "stream" data through this port? If yes, which protocol is used?
I am trying to understand if it works like OBD-II we have in cars. Obviously not exactly the same, but is it similar? Does it stream live data?


texts: What's the difference between a two-blade prop and three-blade?

texts: I read that a three blade can improve climb performance and decrease noise.  How does that work?


texts: Is there a requirement for self-locking / positive locking electrical connectors for aircraft systems?

texts:
Is there any FAA or EASA regulation that dictates the use of locking electrical connectors for certain systems on an aircraft?

Self-locking (ratchet mechanism, bayonet) and positive locking (wire locked) connectors are used on most systems.

But there are also push-pull connectors mainly used on headsets or quick disconnect batteries.

Is there a regulation that prohibits the use of not self-locking or positive locked electrical connectors for certain systems even though they fulfill exactly the same mechaninal specifications concerning vibration, shock and durability?


texts: Is there a way to find what types of aircraft have landed at an airport?

texts: When I was a child, I recall an aircraft landing at my local airport, CSG, I would like to know if airports keep records of what aircraft land there? If so how long do they keep these records, and are the available to the public?


texts: Where, exactly, is the Boeing 727's FDR located?

texts: I'm working on a history report and I am trying to find a diagram that shows where the flight data recorder would have been on a Boeing 727 in 1984, specifically for Eastern Airlines. I know the general answer is "tail section," but I'm looking for a specific location, ideally with a diagram.


texts: Is the descent performance of the PMDG 737-800 accurate?

texts:
I often fly the PMDG 737-800 (with winglets) in my home simulator and most of the time, I find it hard to slow the aircraft down for landing when I descend. Most of the time, I need to deploy the speedbrakes to keep descending without increasing speed. I usually start my descent earlier than the marked top of descent point to make the flight a little smoother.

So I was wondering if this is a bug or if the real aircraft actually behaves like this. I have wondered about this for some time. I can only dream about becoming a pilot and find out myself cause of my bad eyesight.

Here is a video on YouTube of me landing the 737 where I had to deploy speedbrakes.

Since this video is getting a little outdated: I can no longer recall exactly the payload or weight of this aircraft. But I normally fly with a heavy payload.


texts: Why were most of the first-generation-Learjet wing mods never approved for the Learjet 23?

texts:
First-generation (straight-wing1) Learjets (the 23, 24, 25, 35, and 36) are, rather infamously, beasts to fly, due in part to their hideous stall behaviour;2 due to their flow-separation-prone laminar-flow wings, they have a tendency to stall at a fairly high speed with little to no warning and roll uncontrollably to one side, something that caused a considerable number of fatal crashes upon landing.

For this reason (and others), a number of modifications were devised over the years for the first-generation Learjet wing to improve its flight characteristics:

The Dee Howard-Raisbeck Mk. II wing mod, which lowered the aircraft's stall speed considerably, was released in 1975.
The following year, Gates Learjet responded with the Century III modification pack, which both lowered the aircraft's stall speed (by modifying the cross-section of the wing's leading edge) and modified the aircraft's stall-warning system to alarm earlier if the aircraft's angle of attack is increasing rapidly.
In 1979, the Softflite modpack (a set of stall strips and wing fences installed on the upper surfaces of the wings) became available; it considerably improved the straight-wing Learjets' stall characteristics, changing their behaviour from an abrupt stall and violent rolloff to a gradual, wings-level stall.

Learjet 23 owners, however, are unable to benefit from most of these improvements, as most of them were never approved for use on the 23.  The Mk. II modification was approved for the Learjet 23, but the Century III and Softflite modpacks - with the former's improved stall-warning system and the latter's benignified stall characteristics - were made available only for the Learjet 24 and up:

  The manufacturer's Century III and Softflite wing modifications to improve the airplane's slow speed and stall characteristics have not been approved for the [Learjet] Model 23.  The Dee Howard-Raisbeck, Mark II, a similar wing improvement modification, has been approved for the Model 23, but the accident airplane was not equipped with this modification.  ...  [NTSB AAR-83-01, page 16 (numbered as 13).]

Why was the Learjet 23 excluded from most of these stall-protective modifications?

1: Technically, the wings of first-generation Learjets do have some sweep.  However, the wings' sweep angle is too small to make a meaningful improvement in the aircraft's flight characteristics; the 23/4/5 have the leading edge swept at 13° and the trailing edge unswept (giving a quarter-chord sweep angle of only 9.75°), and the wings of the 35/6 are based on the 23/4/5 wing, with the addition of completely-unswept wingtip extension panels which give it an even lower effective sweep angle.

2: Other bad points: an original autopilot with a great tendency to produce large, spontaneous pitch inputs in either direction, a tendency to dutch-roll violently if said autopilot failed or was disconnected at cruise speed, or if the aircraft's yaw damper failed or was disconnected at any time except when configured for takeoff or landing, a mach-tuck susceptibility best described as "extreme" at not far above MMO on an aircraft with easily enough engine power to exceed that limit in level flight (aggravated by an overmach-recovery procedure which, as it turned out, was very likely to send the Learjet into an unrecoverable dive), et cetera, et cetera.


texts: Does ducting help to stabilise heavy lift drones?

texts:
I'm looking to build a UAV that is extremely stable. It doesn't have to be fast, it doesn't have to be agile, but it will have to carry up to 50lbs (agriculture focused UAV that has to operate for at least 8 hours at a time) over private land (where the drone is authorized to be, and with FAA registration) at an altitude of about 15 feet.

Is ducting the way to go here?

I'm looking to do a quadcopter with a very very low center of gravity right now because of it's inherent stability. Is ducting or more rotors the way to go here? And I have very few specifics because I'm still working on the basics of the platform. It will have to carry a lot of weight and potentially deal with being thrown off balance by a rover getting caught on plants.


texts:
I am interested in the case of Qantas Flight 32 and similar incidents, where there was a fuel leak after a number two engine explosion due to the disintegration of the turbine disc. It was a very dangerous situation since the fuel leaks were very close to the failed, then burning, engine. And to make the matter worse, fuel dumping system was down due to hydraulic failure.

Although the crew managed to shut it down, the engine took considerable amount of time for fire to be extinguished completely.

I wonder in those kind of situations, could adding eventually a "drop-engine-on-fire" feature make the situation less dangerous?

You may consider the following:

Modern airplanes could fly with one engine out.
Dropping the engine must be in water to not cause any harm to the people below.
Usually, the engines are mounted on the wing only at three points.
Even if the main evidence of the investigation (that is, the burning engine) will be lost and maybe never found, I think that saving lives is a bit more important.

EDIT :
In response to comments, I think that every feature (even if its seems silly) is subject to pro-con studies. For example, Boing 747 had fuse pins  that are designed to break cleanly in case of excessive loads/vibrations.


texts: Who authorizes low visibility takeoff operations for airlines, and what is required?

texts:
A previous question pondered the legality and safety of low visibility Part 91 takeoffs. I am wondering about the requirements for low visibility takeoff for commercial airline operators (e.g. Part-121 scheduled operations). I know of authorizations for operators down to 600 RVR (though I believe I recall 300 RVR for one carrier out of DEN), and various requirements for other increments below standard takeoff minima.

My question is:

Which RVR are authorized and what ground equipment requirements need to be met to use them?
What authorizes (regulation? op spec?) these reduced visibility operations?


texts: Should an aircraft registration match the flag next to it?

texts:
More specifically, I have noticed that on several of the aircraft of Blue Panorama Airlines, even though they are an airline based in Italy and the Italian flag (together with the EU flag) were on each of the aircraft's tails, they all had an aircraft registration prefix of "EI", which is obviously the prefix for Ireland.

Why do the flags and registration prefixes contradict?
Even if there is a reason for that, why does an Italian airline have aircraft registered in Ireland?


texts: How can I tell if a rental aircraft has been maintained in good condition?

texts:
When I rent a Cessna (typically old) from the local airport, how concerned should I be that the plane may have been abused at some points over many years (over-load forces, hard landings, over-rev'd engines, etc.)?
Perhaps the question is "are the plane's standard inspection schedules enough to catch such abuse?". Should I be concerned?


texts: Why would only a specific model of drone be allowed to fly over crowds?

texts:
The FAA allowed CNN to fly a drone over crowds at extremely low altitudes. Its scope is within the UAVs. Only a specific model/type is allowed to operate on these flights.

Why is this model of drone allowed to do such a thing, and others not? CNN claims that it is to minimize the damage to people, if the drone crashes or something.


texts: Do turboprop and piston engines perform differently at higher altitudes?

texts: When flying at higher altitudes, does it matter if you have a turboprop vs a piston engine driving a propeller?


texts:
Single-engine aircraft (one propeller on the 'nose')

Why do propellers on aircraft have a slight offset angle? I have picked up this information that the rotational axis of the propeller is not aligned with the roll axis of the aircraft, but I don't know why and by how much it is off. I also don't know the direction in which the propeller's rotation axis pointing (other than 'roughly' in roll axis direction).

Is the direction of the propeller's rotation axis important?

Does the direction of the propeller's rotation have any influence on it?

How big are these angles between aircraft roll axis and propeller rotation axis typically?

Is this concept only useful for propellers?


texts: What are these autonomous, shape-shifting indoor neutral-density craft I read about?

texts:
This may be on the edge of off-topic. I am trying to read more about a technology where generally autonomous (though could be sent commands), neutral-buoyancy craft were navigating indoors, in large spaces. The image I have in mind - vaguely - is of huge, transparent whales swimming around in the air in a giant atrium, never colliding with each other or the walls or floor or ceiling.

I'm trying to read more about how the sensing was done and the algorithms used, and how it was made to be so light weight, and what kind of propulsion they used that was also so light weight.

I seem to remember that they were possibly even changing shape in order to change direction.

But all I have is this image in mind from roughly 3 to 6 years ago, and so far I can't find search terms that give me anything even close. There were several articles and videos about this at the time.


texts: How can lift be less than thrust that is less than weight?

texts:
Physics in schools teaches two contradictory and mutually exclusive things:

That the upward lift force on an airplane in flight equal its weight (Lift = Weight = Mass x Gravity). This is based on applying Newtons 2nd law of motion (F = ma) to the airplane in flight.
However, modern commercial airplanes like the Boeing 747–400 can fly with thrust-to-weight ratio as low as 0.3. Here the engine thrust is only 0.3x the weight of the airplane, but this thrust is sufficient to push the airplane forward and generate enough lift to fly.

Therefore the upward force required for lift and flight must be a lot less than 0.3x the weight of the Boeing 747-400 (Lift < Thrust < Weight). Both statements cannot be true. Which is correct?


texts: What Blackbird variant is the one at the Kalamazoo Air Zoo?

texts: Which one is sitting at the Air Zoo (Kalamazoo Aviation History Museum)? What variant is it?


texts: How to calculate the variation of Z force with elevator deflection (Zδe) in Nelson for pitching dynamics?

texts:
I have been trying to model the pitching dynamics of a General Aircraft (Nelson, "Flight Stability and Control").  I need to use the Zδe which uses CZδe parameter in the control matrix B, but Nelson provides no method to find it.  The state space equations are:

]2


texts: What US airports have approaches with LAAS?

texts:
LAAS (Local Area Augmentation System) is a ground-based GPS augmentation system, intended to be placed at airports to get position accuracy down to around 3m (~10ft) from WAAS's 10m.

I've read that it has been installed at a few airports, but can't track them down; I've also heard, anecdotally, that installation has ceased as WAAS is more than sufficient.

Is LAAS still being installed, and if so, where can one fly a LAAS approach?


texts: What advantages are there to operate a corporate flight department under Part 135 as a separate entity instead of in-house as a Part 91?

texts:
This question specifically involves FAA regulations in the U.S.
Some U.S. corporate flight departments will set up a separate business entity for their flight operations to limit the liability of the parent company. Because this business operates with on-demand passenger transport for compensation as its primary business, it must be operated as a part 135 (or 125 if they are running big ships) instead of part 91. In some cases, this new subsidiary will provide additional revenue stream by servicing outside clientele in addition to meeting the travel needs of its parent company, and sometimes they remain exclusive.
If a corporate flight department doesn’t want to use their aircraft to supplement income with charter flights, is liability the only reason to set up and operate as a Part 135 instead of keeping it Part 91?
Are there any other reasons, aside from liability and supplemental income, to bother with a 135?


texts: What can I do to prepare for private pilot training? (India)

texts:
I am an aviation enthusiast from India. I am 24 now and want to be a hobby pilot after 1 or 2 years (I need to save money to afford training).  I want to move up to twin engine aircraft as well.

Since I have fair amount of free time and can understand the concepts clearly with no time pressure, what should I start doing now that will help me tremendously when I train to be a pilot (reading books or doing any other stuff)?  What should be my plan of action?


texts: What is this runway marking on Kirkwall Airport's runway?

texts: What are these markings on Kirkwall Airport's runway? From where they are on the runway, they seem like the touchdown markers, is that what they are?


texts: How to know that single engine aeroplanes are not allowed to depart on the TETAN SID?

texts:
I'm studying for my IR exam and came across another tricky AIP question.

  Which of the following statements about the TETAN 1A standard departure chart are correct?

  Single engine aeroplanes are not allowed to depart on this SID >>> marked as correct
  Aircraft equipped only with RNAV (GNSS) avionics equipment may not fly this procedure
  If the SID is in force, an aircraft that cannot comply with the minimum climb gradient on the chart may not take off
  The altitude at which Cape Town Radar control must be cancelled will not be confirmed in the ATC departure clearance

I would say #3 seems more likely because of the terrain. However, it says that that if an aircraft cannot comply with the climb gradient, it just needs to notify ATC.

As for #1... how would one determine that? I've had a look at the TETAN C and TETAN B Dep charts and they don't indicate anything about being single engine or multi engine aircraft limited either.

I'm located in South Africa and we use ICAO as a reference for most of our regulations.

(Click here or on image to view full size, or here for the PDF)


texts:
What is the maximum taxi speed and who defines it? has a lot of interesting thoughts and facts about what maximum taxi speed is admissible or practical. It brings me to this new question: how does a pilot know how fast he/she is going when on the ground, apart from just looking out the window?

Afaik most planes only have an airspeed indicator, which I suppose is not of much use while taxiing due to surface winds being in the same order of magnitude as ground speed. Also I wonder if an ASI has any usable accuracy near the bottom of its range. The same might be true of GPS speed indication.

Did some more research and found out GPS is much more accurate than I thought it was. http://www.ncbi.nlm.nih.gov/pubmed/15519597 and other sources find it better than 0.5 ms-1 most of the time. I guess that is better than what can be calculated from wheel speed, especially with big, fast wearing tyres.


texts: Is it possible to power a B-52 bomber with four bypass turbofan engines?

texts: Is it possible to power the B-52 Bomber with 4 bypass turbofan engines instead of the eight in its current configuration? They would have less noise and be a lot more fuel efficient.


texts: Do military pilots use amphetamines or other stimulants?

texts:
Related to this question: Do military pilots have flight & rest hours regulation?

According to the wikipedia article, amphetamines were commonly given to Allied pilots.

Are they still in use today?


texts: Can a plane fly without the Vertical Stabilizer?

texts: What would happen if a plane (for the sake of the question let's say that the plane is an Airbus A380) lose its  Vertical Stabilizer?


texts: Why are the lights inside commercial airplanes turned off during take off and landing?

texts: Before landing and taking off, I notice the lights inside commercial aircraft are greatly reduced. I don't buy the explanation of power saving in case full thrust is needed as nowaday lights don't need a lot of energy and the crew says we can use the smaller reading lamp to continue reading. I suppose this is something to do with security but I don't understand what.


texts: Why don't horizontal stabilizers have winglets?

texts: Winglets are used to reduce induced drag on the main wings of an aircraft as per explanations on wikipedia. Since they are very effective I was wondering why they are not installed also on horizontal stabilizers. For sure there must be some sort of induced drag being generated on horizontal stabilizers too as they are cutting through the air just as the main wings do. So why aren't there any sort of "minified" winglets available as an aftermarket installation (or, at least, I haven't ever seen some myself)?


texts: Can I preheat my C150 by placing a space heater in the cabin?

texts:
I have a C150 in a hangar, but no jet heater.  I was planning on just putting a directional space heater (an FH-06B) in the footwell and opening the cabin heat to let the heat through to the engine.

I figured that running that for an hour or two would be better than 20-min with a jet heater and almost as good as a heated hangar.

Testing this out, the rudder pedals get very hot, but not so hot that you can't touch them.

Are there any flaws with this plan?


texts: What makes the F/A-XX twin-engined tailless fighter controllable with engines out?

texts:
There are operational tailless aircraft such as B-2 spirit, X-45.
It seems yaw stability/control at slow speed is achieved aerodynamically, using either split elevons (B-2) or adjacent elevons deflected in opposite directions (X-45) Combined with negative wing tip twist angle, both solutions increase drag / relative swept angle, and by the way, yaw stability. Also note both examples have a very small vertical surface ahead of CoG.

(Left, Right)

On the other hand, looking at this picture of a F/A-XX Boeing concept, it seems vertical surface ahead of center of gravity is quite significant, and forward swept trailing edge is in contradiction with aerodynamic stabilisation using split elevons.

One might think this isn't such a big issue since this concept might use permanent vector thrust adjustments on yaw axis.

Question is : Does it fly with no yaw thrust vectoring?

Edit: One other issue affecting yaw stability is forward swept elevons. Their "split brake" efficiency decreases while sideslip angle increases :

(Source)


texts: Can a SIGMET last less than initially forecasted?

texts:
Lets say I have a SIGMET that says VALID 310800/311200.

Is it possible that by 1100 the SIGMET would not be active anymore or it will always be valid until the published end time?


texts: What are the meanings of these terms used in ATC ground communications?

texts:
Regarding ATC ground communications, what/who are the following callees? Are these aircraft, or vehicles, or people?

[Airline name] maintenance
[Airline name] tug
[Airline name] mechanic


texts:
In a recent question, one of the answers states:

MCAS has nothing whatsoever to do with stall recovery or stall behaviour.

It was implemented strictly to make the MAX's pitch stick force response in certain regimes match older 737s, to avoid an additional training requirement necessitating Sim time.

But after reading this article, I'm confused about what exactly MCAS was intended for, as I thought it was stall recovery.


texts: What crosstrack should I have during a holding pattern?

texts:
I want to know if the ATC is expecting a maximum crosstrack depending of the plane's speed.

I've learn to be at 2.2nm for my holding (with 175kias) but is it just a distance to help me or a rules ?

I think that my protecting side is higher if my speed is higher too but can I use the whole protexting side  ?

Thx


texts:
If we know the helix angle is 3angle, forward speed is 150mph, and rotational speed of propeller is 1500rpm

How can i calculate the blade angle of propeller ?


texts: What is the requirement for fire fighting equipment on board a passenger flight?

texts:
What is the legal requirement regarding fire fighting equipment on a passenger flight, e.g. fire extinguishers and fire hoods? I imagine that the number is proportional to the airplane's max capacity.

I'd prefer ICAO since it applies internationally, but if there is none, a FAA reference would be a good as well.


texts: Is there a way for the helicopter rotor to get its power half by wind, half by engine?

texts:
Imagine a gyroplane, if something happen mid-flight (when the plane is basically an autogyro and the engine provides no power to the helicopter rotor) and just the wind generated by forward flight can no longer turn the helicopter rotor enough to provide enough lift, could the engine partially take over? Like using the engine to provide just enough power, with the rest provided by the wind, so the helicopter rotor could spin enough?
I don't want the plane to autorotate downward. I want the plane to keep flying, but using the engine to increase the rpm. If the incoming wind could turn the top rotor in a certain rpm, could we increase the rpm using the engine? In my memory, rotodyne could do this because it uses a tip jet, but what if we use normal piston or turbine engine?


texts: Does a lean mixture result in a higher cylinder temperature for a given power setting?

texts:
From what I know over rich mixture help cools the engine due to evaporation process and lean mixture do the opposite.
So why this graph showing when reaching around peak EGT the opposite happens:


texts: What are some examples of warning areas and restricted areas?

texts:
Can you please give me some examples of warning and restricted areas?

How can an aircraft enter these areas? What are the procedures you have to follow before entering them?


texts: Tiny margin between VFR cruise and over Class C?

texts: Our class C airspace at KRDU has a 4400 ceiling. If I fly Westbound above the airspace at VFR cruise, I'm expected to be at 4500. Since this is a tiny margin and I don't want to bust into the airspace by accident, do some pilots fudge on the cruise altitude and create a larger margin for themselves, flying at say 4600? I'm a lower hour pilot and while that's no excuse to bust minimums, just asking what you all think. Yes yes, flying at 6500 is also an option but this was a rather short XC scenario, plus let's assume a cloud layer at say around 6000MSL. :-)


texts: How is the A320neo life span calculated?

texts:
I read an article saying that the new Airbus A320neo life span is based on monthly cycles instead of hours or takeoff landing cycles, is this correct?
If so can I understand how it’s calculated based on monthly span?
Any external documents explaining this method will be much appreciated
Thanks


texts: Can an empty 747-400 with minimal fuel take off on two engines?

texts:
This is a fanciful question. 747s are allowed to take off on 3 engines for maintenance ferries (I did a couple), but a 2 engine takeoff is not a practical or legal consideration. However, my gut level feeling is that it could be done in optimal conditions, but I'm interested in what the more technically oriented people here have to say.

The aircraft for this thought experiment is a 747-400ERF, a freighter with a basic operating weight of 351,088 lbs and a max takeoff weight of 910,000 lbs. Let's say we want to take off and make a 15 minute swing about the countryside around Moses Lake, WA with its 13,500 runway, elevation 1189 feet, on a STP day with no wind. It's flat land, there are no departure or arrival path obstacles.

We want to land with no less than 15,000 lbs of fuel, and the takeoff and flying is going to take around 20,000 lbs. Thus our takeoff weight is going to be around 386,000 lbs, which is roughly 42% of the max takeoff weight.

We have half our engines inoperative, but we are significantly less than half as heavy as the max takeoff weight. To make it easy, let's say that engines 2 and 3 are operating (the inner most engines on each side).

So, what say you?


texts: What units should use for velocity prediction equations?

texts:
I'm not an expert aviation but I'm designing my own RC Plane and I wanted to estimate the maximum velocity using equations (15-20) from this paper. Honestly, I am not quite sure on the units to use for the Clmin equation and the Vmax equation, because when I try to apply the equations I end up with unreasonably high velocities.
The units I've been using for the parameters are:
$[W]=\text{lb}$
$[\rho]=\text{lb}/\text{ft}^3$
$[S]=\text{ft}^2$
$[V]=\text{ft}/s$
$[P_\text{max}]=\text{Watts}$


texts: Could box-wing aircraft be the plane of the future

texts: I've read that box-wing aircraft can reduce wingtip vortices caused by induced drag hence saving up a lot of fuel and hence able to carry more passengers. Would we able to see such aircraft in the near future?


texts: What are the aircraft requirements to legally offer commercial sightseeing flights in a C-172?

texts:
When I retire in a couple years I want to fly my 172 and make some money. Even if I just break even that's ok.  My CFI certificate has expired and I don't want the hassle of having it re-instated. I do have a commercial pilot license.

What would it take to give "scenic airplane rides" legally (so I have insurance). I read far 91.147 but it says nothing about the airplane itself.


texts: Is it legal to overload a plane in Alaska?

texts: Is it true that it's legal to fly a plane over max gross weight in Alaska? If so, what are the rules?


texts: Are there any pitfalls to be wary of when purchasing an "umbrella" insurance policy?

texts:
Typically, a pilot will have airplane insurance (or renter's insurance, if flying un-owned aircraft), car insurance, home insurance, life insurance and then for good measure purchase an "umbrella"-type insurance (usually up to $1MM). Have there been cases where this wasn't enough insurance, or the pilot thought he or she was insured but there was something unforeseen that rendered his insurance policies ineffective of shielding him or her from liability?

This question is specific towards American pilots, in this case if would be for an "average" person, owning/flying a small single-engine piston airplane and a net worth of less than $1MM.


texts: Are General Aviation tires filled with Nitrogen?

texts:
Long story short, I'm working on a concept for a book.
We all know why commercial aircraft have nitrogen tires, but my question is if GA aircraft have nitrogen tires, or are they just filled with helium, oxygen or any other gas? My theory is that commercial aircraft are heavier, so probably need nitrogen tires, whereas general aviation aircraft are much lighter, so wouldn't be needed to withstand as much surface friction, meaning it may not need a more heat-prone gas for the tires, like nitrogen.


texts: How does the FAA determine which format of location identifier to assign to an airport?

texts:
In the U.S., FAA location identifiers are assigned to registered aerodromes. However, these can have different formats:

3 Letters (e.g. ORD)
1 Number and 2 Letters (e.g. 1AD)
2 Numbers and 1 Letter (e.g. 25M, 8M1, or M72)
2 Letters and 2 Numbers (e.g. TN01, 1CA3, or 50SD)

How does the FAA determine which of these formats should be used when assigning the identifier for an airport?


texts:
Do large aircraft accumulate water in their tanks?

If so, how is it drained? How often is it drained? At what rate per hour does it accumulate? If not what was done to circumvent the problem?


texts: Why is a 0 kt, vertical climb in a helicopter not safe near the ground?

texts:
In the "Test Pilot" column in the July 2017 issue of AOPA Pilot, one of the questions was

  From reader David Franklin: If a given helicopter has a best rate-of-climb airspeed of 60 knots, its best angle-of-climb speed would be _____ knots.

The answer provided

  Assuming a no-wind condition, zero knots of airspeed would result in a 90-degree climb angle. This would be neither safe (near the ground) nor efficient but certainly would be effective.

makes intuitive sense (climbing straight up gives the best angle, of course).

But why is it not safe near the ground? Does that change if there were wind (and no correction for the wind were applied)?

A suggested duplicate indicates reasons why going straight up is not as efficient, but does not mention the safety aspect at all.


texts: Was the F-4 Phantom the only fighter to be in service for the US Navy, Air Force and Marines?

texts:
As is stated here:

  Furthermore, the F-4 came in both ground- and carrier-based models and
  served in the U.S. Air Force, Navy and Marines. The only other
  frontline fighter to serve in all three services before or since is
  the F-35.

Is that correct? Was any other fighter used by all three services?


texts: What factors cause a turbine aircraft to have decreasing fuel burn over time?

texts:
Consider a fictional aircraft with a fuel schedule similar to the following:
1st hour - 10,000 (lb or kg, doesn't matter)
2nd hour  - 8,000
3rd hour  - 6,000
4th* hour - 5,000
 * and subsequent

As we can see the fourth hour of flight burns only half the fuel of the first hour, so fuel consumption is a function of time.  Is the decreasing weight of the aircraft as fuel is burned the only reason for this increase in fuel efficiency, or are there other influences?  For example if a jet launches with half tanks versus full tanks, would you use the same 1st hour fuel schedule?
I may be way off base here, so if there are fundamental errors in my question, please correct me.


texts: What is this aircraft and its submarine?

texts: I got this picture from an anonymous source and I'm curious to learn more about its mission and I want to know if it's a genuine picture. It happens to be a submarine aircraft carrier.


texts: Would atmosphere floating inside an airship be counted towards the mass of the airship?

texts:
Airships are filled with hydrogen.  However as pointed out by Peter Kampf in the answer to the question below when an airship is on the ground only a portion of its hydrogen cells are filled with hydrogen.
During WW1 Zeppelins began their missions with Hydrogen cells at 33% full. How did this provide enough lift to get off the ground?
This chart details the hydrogen density in a given airship before takeoff.

LZ104's cells are only filled to 42% at sea level.  Does this mean that below the hydrogen cells sits an empty volume of air equal to roughly 58% of the volume of the cells?  If so is this air counted towards the mass of the airship?
I ask because water in a ship's hull makes it heavy and sink.  Why wouldn't air in an airship make it heavy and fall to earth?  Or would it?


texts: Is designing a small GA airplane with a wing loading of 20-25 lbs/sq ft a bad idea, or is that wing loading too high?

texts:
Is designing a small GA plane like the following a bad idea?
This question is not the same asking if a an airplane with a traditional design is safer with a lower wing loading.
This question specifically asks if there are any reasons not to design a small slow landing plane such as a non-USA ultralight with a specific wing loading of 20-25 sq ft, and gives specific design suggestions to counter against popular reasons why an airplane shouldn't be designed at that wing loading.
Is designing a small GA plane like the following a bad idea?
Similar to the Cri Cri but with a wing loading of 20-25lbs/sq ft, slotted flaps, similar 17% airfoil to a Zenith 701, for low a weight spar, wing twist and vg's for better stall resistance,  twin engine, MTOW of 600 lbs, so wing area of 30 sq ft, 15 ft span, 2 ft chord, and a stall speed of 30-45mph (assuming all the math works out)?
This reduces the argument that high wing loading planes must land at a high speed and use low profile wings, which are easier to stall.
It seems many small airplanes are designed in the 10-14lbs/sq ft range, except for the BD5 at 17 lbs/sq ft (popular longer wings), and Rutan's Catbird at 45lbs/sq ft.
Wouldn't smaller wings, smaller spar, lower weight, less drag and less horsepower requirements be advantageous?
Approximate wing loading of various aircraft:
Cessna 172 - 14lbs/sq ft
CriCri - 11
Zenith 601 - 10
BD5 - 17
Rutan Catbird - 45lbs/sq ft


texts: I have an Australian CPL, what do I need to fly in Indonesia?

texts:
If I have an Australian CPL can I fly in Indonesia?

How likely am I to obtain employment if I have 250 hrs. flight in Indonesia?


texts: What is the battery voltage for a Supermarine Spitfire?

texts: I am used to modern aircraft being 28V systems. I found an article saying that a trolley AC plug in battery used to start WWII aircraft was 12V. I'm trying to confirm or disprove this.


texts: What is the cart and cable connected to this plane?

texts:
During boarding I noticed many times that planes are "connected" with some orange cable.

It's curious to know what is it. Does anybody knows?


texts: What are Mode C requirements with ADS-B 978?

texts:
ADS-B out is available on the 1090 (Mode S) band, and can even be implemented as a firmware update to some Mode S transponders.

In the case of 978 ADS-B Out, I believe that it is still necessary to keep operating a Mode C transponder for operations where Mode C is currently required, as noted in This video at 16:25, in order to work with TCAS systems.  Continuing on to 41:24, there is a recommendation stating that if a Mode C transponder fails, it should be replaced with an ADS-B "out" transponder.  Here are my questions:

Is there such thing as a 978 transponder which will meet ads-b out requirements and eliminate the need for Mode C, or does this recommendation essentially mean that you move to a 1090ES transponder?
Perhaps this recommendation is assuming that there was no ads-b out at the time.  Given an aircraft with a failed mode-c transponder, what equipment options which meet the mandates are worth considering for GA aircraft?  Apparently John Zimmerman does not recommend Mode C + 978 out.  It appears he recommends 1090ES.  Either one of these would seem to benefit from having 978 in.  I can see no advantage to 1090ES in, as it appears to offer only a subset of the 978 services, unless it was desired to be able to receive 1090ES air-to-air or our operate outside the US.


texts: Which computer controls auto thrust on an Airbus A320?

texts:
An Airbus A320 has seven computers that control flight surfaces:
two ELAC, three SEC, two FAC, and two AP (autopilot) computers.

Is there an separate computer that controls auto thrust, or is this controlled through one of the above?


texts: What happens at a ramp check when I forgot my license and medical?

texts: I wonder what happens if I would get ramp checked and don’t have my license and medical with me. Especially in EASA territory. Anyone ever had this case?


texts: I watched this video of the Raytheon SDB II and noticed that it seems to have no control surfaces on its wings, just the four fins on the tail. How do these fins work to alter the attitude of the SDB and other missiles or aircraft using the same scheme? For example, if it were to pitch downwards, which fins would need to move and in which direction?


texts: What is this little strake on Cessna 182 vertical tail?

texts: can somebody explain what is the reason of mounting this little horizontal strake on a Cessna 182 vertical tail?


texts: Why do some airports park the aircraft backwards at the gate?

texts:
(YouTube) Push-in at Dortmund Airport.

While at most airports, aircraft park at the gate facing the building, there are some airports that park aircraft backwards, e.g., Dortmund Airport (shown above), and London City Airport. After arrival and engine shutdown, aircraft are then pushed back into their parking position.

What is the benefit of parking aircraft backwards?


texts: Do any newer production aircraft use venturis as a backup vacuum source?

texts:
I began my flight training in a Cessna 120 with 2 venturis as the source of vacuum for my DG and TC. They worked well in flight.

Are there any aircraft with deployed/deployable venturis out there? Other than my 1946 vintage C-120 which is also my birth year.


texts: Credible Sport Project: Is it possible to revive the idea with modern avionics?

texts:
Synopsis: On a secret mission to rescue 52 hostages in Iran, Operation Credible Sport was created. The project consisted of a modified Lockheed C-130 Hercules and developed so that it would be able to land on a runway as short as a football field. In order to shorten the landing distance, the engineers retrofit the planes with rockets.
These rockets slow the planes as it lands and provide extra propulsion upon take-off.
During training in October 1980, just days before the surgical operation, "Operation Credible Sport" derailed.As the plane came in for landing, the pilot mistakenly fired the rocket before the wheels touch-down. The plane loses lift and slams in the tarmac.

For illustration purposes, here is a short video summarizing the event: Credible Sport Test YMC 130 H

Now, technology has come a long way since the 80's; avionics have greatly improved and the aviation industry even came up with the fastest transistor ever-created in 2009 thanks to Northrop Grumman.

That being said, would it be possible to revive this project and allow an automatic firing of the rockets by a computer system rather than by a manual control of the pilots(given that it was human factor that doomed it to failure in the beginning)?


texts: Recently, a friend asked me why aircraft registration details are made public since related car license plate numbers details are more regulated in access by law. Me, being an avgeek and taking this for granted, do not know why this is. Why are aircraft registration details made public?


texts: How much force is needed to tow an airliner?

texts:
Airliners are often (almost always actually) pushed back by a tug or a tractor to leave the gate. The tug can also tow an aircraft that cannot taxi by itself.

How much force is required to pull or push a large airliner on the ground? In other words, what is the horsepower of these tugs?

EDIT: By large airliner, I mean Boeing 747 / 777 / A380 type, the ones which ATC append "Heavy" (or "Super") to their call sign.


texts: Why are emergency water landings the majority of the pre-flight safety briefing if they're so rare?

texts:
According to an article published in the New York Daily News a few months after the "Miracle on the Hudson", when US Airways flight 1549 safely landed (watered?) on the Hudson River to the survival of all 155 souls on board, this incident was only the second ever emergency water landing that did not result in significant injuries and casualties in commercial aviation history.

And yet, the safety briefing at the beginning of every commercial flight adhering to aviation regulations spends more time discussing water landings than nearly any other topic, focussing on how to use life jackets, where to find them, where to inflate and where not to inflate them, how to use the emergency rafts, and so on.

Further, a very large amount of weight on commercial aircraft is devoted to equipment chiefly or entirely present to aid in water landings, with most commercial aircraft today having four or six emergency life rafts, hundreds of life jackets, and even the design of the aircraft itself adhering to minimum float time requirements.

With water landings so rarely attempted and even more rarely successful, why is there so much emphasis put on the current, ineffective methods? In other words, if water landings with current methods and technology generally don't work, why hasn't this changed?


texts: How could the B-29 bomber back up under its own power?

texts:
I was watching some footage of the Enola gay

I was interested in the part where the plane was backing up over the bomb (starts around 18:27). It appears to be doing this under its own power with the propellers running. Could the B-29 reverse some propellers to do this?


texts: Is it legal to use handheld radios to listen to airport frequencies in Australia?

texts:
I am a student pilot at ABX (YMAY) in Australia. It is a single engine aerodrome with three frequencies:

123.25;
125.80; and
the ATIS frequency

I live very close to the airport, directly under the base/final turn. Would I be able to purchase a handheld radio that I could use to listen to the ATC and practise my radio calls? Is it legal?


texts: What, effectively, does a navaid being unmonitored mean?

texts: I saw a NOTAM about a VOR being unmonitored. I think this means that the voice capability of the VOR frequency is not in operation/nobody is listening. Is that right? If so, it just seems like something nice to know but doesn't affect the navigational capability of the VOR, right? If a VOR is unmonitored can I still use it for navigation, such as for a VOR/DME approach?


texts: Why can’t the newest high-bypass turbofans run at their EPR, temperature, and RPM limits simultaneously at sea level?

texts:
The General Electric GE9X turbofan (used on the 777X), unlike the vast majority of turbofans before it, did not undergo the traditional triple-redline test (where the engine is run for a prolonged period of time while simultaneously at redline EPR, redline temperature, and redline RPM), because it is, apparently, incapable of doing so except at high altitude:

  ... Before certification, final tests include a full durability block test, replacing the usual “triple redline” test at maximum temperatures, pressures and speeds, as modern high-bypass ratio engines cannot achieve all maximum conditions near sea level...

In contrast, the GE9X’s immediate predecessor, the GE90 (used on some first-generation and all second-generation_777s), did undergo triple-redline testing before entering service, and again before the release of the high-thrust variants used on second-generation 777s.1

One would expect, intuitively, that it would be easiest to achieve triple-redline conditions at sea level, as fuel and air flow (and, thus, RPM, EPR, and thrust) are highest in the dense low-altitude air,3 and the increased cooling from the additional airflow should be just about balanced by the increased heat generation from the additional fuel burned.4

What makes it impossible for very new turbofan designs to reach all three redlines simultaneously at sea level?

1: Setting a record for the highest thrust ever generated by a jet engine (569 kN, or 64 short tons for you Americans) in the process, which stood unbroken until it was eclipsed by a 597-kN (67.2-short-ton) GE9X test run in November 2017.2

2: Ironically, while the GE9X is larger and has a higher record thrust than the high-thrust GE90s, and is required to power an aircraft just as heavy (and soon to get much heavier still, with the 777-10) as those using the latter engine, its rated thrust is considerably lower (470 kN [52.5 short tons] versus 510 kN [57.5 short tons])!

3: Although not by very much, as the maximum thrust available from (and, thus, fuel and air consumed by and RPM and EPR attained by) a turbine engine remains nearly (although not completely) flat up to very high altitudes.

4: These effects would be even more pronounced on an actual aircraft than in a test stand, due to the higher thrust settings needed to counteract the increased drag from low-altitude flight and the increase in airflow through the engine (and, thus, in fuel flow, as well) resulting from the ram effect of the aircraft’s (and, thus, the engine’s) forward motion through the air.


texts: How to calculate the wing chord of the aircraft Aero A.10?

texts: Can anyone explain how to find the wing chord of the aircraft Aero A.10? Given Wing Span = 46.6 ft and Wing Area = 549 sqft. Thanks


texts: How to find if an aircraft is inside an airspace using latitude and longitude?

texts:
I have the data of latitude and longitude of $n$ points on the boundary of the airspace of a country. I also have the coordinates of the current location of an aircraft. Using this data, how do I find out of the aircraft is inside the airspace or outside.

For the sake of simplicity we can assume the boundaries of the airspace form a convex polygon.


texts: When temperature increases what happens to the air molecules and aircraft while landing and takeoff during hot weather?

texts: Just out of curiosity on a hot weather with  temperature increases what happens to the air molecules and aircraft during landing and takeoff?


texts: How do you meet pilots looking for passengers?

texts:
I enjoy being up in the air.  Planes, gliders, helicopters... you name it, I like it.

What is an effective way to meet pilots looking for passengers?

I'm guessing that some pilots would like passengers to have someone with whom to share the experience, or maybe to gather hours for certifications.

I'm not looking to go anywhere in particular.  Although I'm open to flying to any destination, just going up in the air and coming back to the same airport is fine.

I enjoy being aloft in the daytime as well as at night.

I simply enjoy the experience of flying and want to connect with pilots who are looking for some company.


texts: Is this BA15X flight a logistic flight for British Airways?

texts:
Right now (26/11/2015, UTC 17:16), British Airways is flying over the Australian Outback with two Boeing 777-336(ER)s, christened flight BA15 (http://www.flightradar24.com/BAW15/8169bb5) and BA15X, which is slightly ahead (http://www.flightradar24.com/BAW15X/8169237).

Why is this? Is flight BA15X a logistic one? And if not, why did they use an "X" to distinguish between the two instead of another number?

EDIT

I am also wondering: is this going to cost extra money to BA, owing to the new slot they had to purchase or rent for operating a contemporary, second aircraft at SYD?


texts: How does EMAS reduce damage in case of an aircraft overrun?

texts:
I saw a report about Mike Pence's plane overrun today on Twitter link: Mike Pence plane overrun photo on Twitter.

As can be seen there is huge cracks and breaking of the runway but the plane was not damaged. According to twitter this is due to Engineered Materials Arresting System (EMAS). The FAA is adopting a plan to expand the use of this method for arresting overruns on runways that do not have enough land for a runway safety area (RSA).

I am interested to know how this system works. Is it similar to gravel runaway truck arrestors on the steep downhill roads? Do we have any specifications and test data?


texts: What are the unique sounds emitted by Embraer E190-E2 on final?

texts:
I live close to an airport where these aircraft frequently land. When the E2 is between 2-3 thousand feet, something which I can only describe as whale moans, is heard.

I say they are unique because I can’t hear them from other aircraft. However, this airport seldom get heavy traffic, so maybe this sound is common among heavier aircraft—I wouldn’t know.


texts: Nose gear failure in single prop aircraft: belly landing or nose landing?

texts:
Let's say we are flying a single prop airplane with tricycle format retractable gear, such as a Mooney Bravo or a Piper Comache. The nose gear fails mid-flight and is unable to be lowered. Is it safer to attempt a belly landing, or to actually try and make use of the functional main landing gear? What is the standard procedure?

Edits and updates:

Here is the video of a very smooth looking nose landing with a RCMP Pilatus PC-12 I could find
Here is the video of a smooth looking belly landing find I could find

My major concern with the nose landing would be the increased risk of the nose digging in, causing a flip and/or the fuselage to break in half. As pointed out by @acpilot, the probability of this increases according to runway type.


texts: How do "fundamentally unstable" aircraft deal with the risk of computer failure?

texts:
As technology becomes more advance airplanes are becoming less and less stable.  In flight school I learned that it's dangerous to load a Cessna out of it's CG range, and now in college (for aerospace engineering) I'm learning about modern fighters and their fundamentally unstable designs.

A lot of these unstable aircraft are supermaneuverable but rely on computers to fly them more than the human pilot in the cockpit.

I'm sure that these airplanes are thoroughly checked before every flight to make sure the computer systems will perform accordingly, but in the event of a failure what kind of side affects might a pilot experience?

The two conditions I can think of are

No computer aid, but the control surfaces are still "responsive"
The pilot loses all control of the aircraft and none of the inputs work.


texts:
In the history of aerospace engineering in the United States, the X-15 is lauded as a critical and necessary step on the path to manned spaceflight. Throttle-able chemical rocket propulsion systems, reaction controls, and pressurized flight suits were all major design features of the X-15 that eventually found their way into future successful spacecraft.

Given the obvious resources the USSR put into the space race and their numerous successful missions, why did they never build a hypersonic space-plane akin to the X-15?


texts: How does the airflow above an airfoil account for the downward turning-action of the airflow below the airfoil?

texts:
Wikipedia provides an explanation of the lift force in terms of flow deflection and Newton's laws, emphasis mine:

An airfoil generates lift by exerting a downward force on the air as it flows past. According to Newton's third law, the air must exert an equal and opposite (upward) force on the airfoil, which is lift.
The airflow changes direction as it passes the airfoil and follows a path that is curved downward. According to Newton's second law, this change in flow direction requires a downward force applied to the air by the airfoil. Then Newton's third law requires the air to exert an
upward force on the airfoil; thus a reaction force, lift, is generated opposite to the directional change. In the case of an airplane wing, the wing exerts a downward force on the air and the air exerts an upward force on the wing.
The downward turning of the flow is not produced solely by the lower surface of the airfoil, and the air flow above the airfoil accounts for much of the downward-turning action.

In what way does the air flow above the airfoil account for much of the downward-turning action of the air flow below the airfoil?


texts: Are solar / geomagnetic storms real risks for commercial aviation?

texts:
Background

Solar storms/flares are solar events sending particles in space that are potentially dangerous on Earth. From Wikipedia:

  Solar flares strongly influence the local space weather in the
  vicinity of the Earth. They can produce streams of highly energetic
  particles in the solar wind, known as a solar proton event. These
  particles can impact the Earth's magnetosphere (see main article at
  geomagnetic storm), and present radiation hazards to spacecraft and
  astronauts. Additionally, massive solar flares are sometimes
  accompanied by coronal mass ejections (CMEs) which can trigger
  geomagnetic storms that have been known to disable satellites and
  knock out terrestrial electric power grids for extended periods of
  time.

Source

They are rated by the US NOAA on a scale from 1 to 5. For instance, level 3 events occur about once a year:

  S3 (Strong) - Biological: radiation hazard avoidance recommended
  astronauts on EVA. Passengers and crew in commercial jets at high
  latitudes may receive radiation equivalent to approximately 1 chest
  x-ray.

There are also geomagnetic storms listed on the same page.

Question

Is this a real risk for commercial aviation, if so how do airlines treat this risks on affected routes, e.g.:

How are airlines informed?
Are pilot-in-command informed and allowed to veto a flight?
What do they do regarding exposed crews and passengers?


texts: What do I need to power up an EDF engine?

texts: I want to buy a EDF engine (just the engine). What items, such as battery and chargers etc. do i need to buy to power it up?


texts: What is the function of the Apache's Strap Pack?

texts:
I have recently been reading about the issues with the Apache's (AH-64) strap packs. I've read that the strap pack holds the rotor blades on to the hub.

However, it appears the blade also connects to the pitch housing assembly. So I don't really understand the function of the strap pack and why it's failure would cause a catastrophic failure leading to loss of aircraft.

Questions:

What is the Function of the Strap Pack?
Why does its failure lead to loss of aircraft?
Is this a common design on other helicopters?

Reference: Story

Image Source


texts: How easy is it to pull the ejection handle in a Rafale B?

texts:
A civilian passenger ejected from a two-seat Rafale B during takeoff on Mar 20 2019. The investigation is underway as to how it happened, but one of the possibilities discussed is that the passenger accidentally pulled the ejection handle.

Having sat in various military aircraft over the years, I never thought it would be easy to accidentally pull the eject handle.

Is the ejection handle on a Rafale B easier to pull than most fighter jets, or closer to the hands' resting position?


texts: Does an aircraft carrier have a VOR onboard?

texts: I wouldn't think so due to the impracticality of VOR on a moving platform, but aircraft still need to navigate to the aircraft carrier. Would the radial shift around as the boat rocked around? The enemy could use the VOR to literally home in on the carrier as well.


texts:
[I'm referring to an ATC conversation during the military coup in Turkey with an MD83 EP-TAS (ATA TBZ5402).
Can a pilot take off at his own discretion?

To summarize the link: a pilot is begging the tower to be allowed to depart and repeatedly denied due to what the controller describes as a "military operation" or "people in the tower". The pilot indicates the situation is dangerous and even reports seeing gunfire on the ground at one point. The pilot then repeatedly asks for permission to depart "at my own discretion". In the end, it appears that he does not depart.

Would there be any consequences for the pilot? Is he allowed to take off if the situation on the ground is more threatening than in the air? Are there any international regulations in this case?


texts: What is the meaning of ACAI and ATCI in Air Cadets?

texts: For my staff cadet course, I need to know what ACAI and ACTI stand for but I can't find it anywhere. Would anybody be able to notify me of what this means?


texts: How does the ski shape of an aircraft carrier deck help for take off?

texts:
Why is a ski-shaped deck used on an aircraft carrier for take off?

The aircraft needs a particular lift for a particular weight, how does ski assist in take off?


texts:
I'm working on a Python script that takes in metar data and decides if an airport is VFR/IFR/MVFR etc. This is the website that I'm getting the info from:

https://www.aviationweather.gov/metar/data?ids=kbwi&format=decoded&date=&hours=0.

I'm using this website to decide if an airport is IFR/VFR. I understand the visibility requirements, but not the ceiling. What if an airport is overcast at 500, broken at 5000, scattered at 3000? What takes priority to decide the ceiling requirement?

https://www.aviationweather.gov/metar/help?page=plot


texts: What is this "No Hand Hold" thing in the P-51 Mustang cockpit?

texts:
Does Anybody remember Combat Flight Simulator WW2 Europe Series ?
In the P-51, there is a "something" with "No hand hold" text on top of it
What is that ?
Image source


texts: Do modern aircraft still have mechanical sensors as backup to GPS?

texts: A comment here Why does "no aircraft cross directly over the pole"? indicates that modern aircraft use GPS for navigational purposes, which makes perfect sense.  However, do these aircraft also have backup mechanical sensors (altimiter, magnetic compass, etc.) in case GPS signals go haywire or are not available?


texts: How should the Swiss international airlines flight 850 METAR reports be interpreted?

texts:
From the Wikipedia page on the Swiss International Airlines Flight 850 crash investigation, it was stated that the initial METAR did not reflect the situation and the METAR less than an hour (a moment before the approach was started) was drastically different.

Initial METAR:

  EDDT 04001KT CAVOK 30/17 Q1002 A2959 0998 2947 NOSIG.

Later:

  EDDT VRB01KT 9999 FEW040CB SCT120 BKN260 29/17 Q1002 A2959 0998 2947 TEMPO 27025G55KT 2000 +TSRA BKN009 BKN015CB COMMENTS: OCNL LTNG AND CB SW OF STN.

I'm not very familiar with these reports, or how they are generated. From some research it sounds like the second report is much more serious, however I'm having trouble understanding a few things:

  VRB01KT

This seems to suggest variable visible range, but I'm not sure what the 01KT means.

Can someone clarify?

The later report first mentions scattered cumulonimbus clouds, but then says the coverage is up to broken.

Why are there multiple mentions of the same types of clouds?
Are they talking about different height/direction?

The Wikipedia article seems to suggest that there was a massive storm moving rapidly into the area. My understanding is that NOSIG means the weather is not expected to significantly change in the next two hours.

What would cause the initial report to include NOSIG?
Given how much worse the weather seems to be in the later report, why would it take the station almost an hour to file a new report?
Why wouldn't they file a new report as soon as it seemed like the weather was degrading?


texts: Could I build an airship (rigid dirigible) that used a vacuum rather than lifting gas?

texts:
There are other questions (c.f. What gas is used in airships to give them buoyancy?) that discuss the use of lifting gasses such as Helium and Hydrogen in airships. Helium is rare and Hydrogen is flammable.

If one could build a light-enough and strong-enough rigid outer frame, then couldn't one use a vacuum rather than lifting gasses?  At ground level, the frame would only have to withstand 15psi (100,000 pascals), which isn't a tremendous amount of force. Theoretically, a vacuum should provide even greater lifting force than any gas.

Have there been any attempts at vacuum based rigid-dirigibles -- and if not, what are the technical or mechanical limitations to doing so?


texts: Turboprop vs Turbofan: How to compare Specific Fuel Consumption

texts:
I understand that Turboprop engines have a lower Specific Fuel Consumption (SFC) than Turbofan engines, on average. I want to see this for myself by analysis, ideally by comparing values of SFC for typical turboprop engines vs turbofan. As turboprop SFC is usually given as the Fuel Consumption Rate / Power, and turbofan SFC is given as Fuel Consumption Rate / Thrust, it is tricky to directly compare them.

For a given airspeed and altitude, I want to show that a turboprop engine will require a lower rate of fuel consumption to produce a given amount of thrust. Is there a way I can show this without going into too much detail on things like blade pitch, thrust coefficient etc.

Ideally, I want to compare SFC of turboprop engines with that of turbofans, and show that the SFC for turboprop engines at a given thrust is lower.

Thanks


texts: How to get a NOTAM on a Restricted Area?

texts:
Is there any online service to get restricted area NOTAMS?

For example how can I get NOTAMs related to R-2503-D (intermittent by NOTAM 24 Hrs in advance) on Los Angeles Sectional chart?

I found this website but I am not sure how to find by restricted area name.


texts: How big is the radar cross section of a modern glider?

texts:
I heard somewhere that modern glider made of plastic and composite materials are less detectable than other aircraft by primary radar. I wonder how much.
What is the radar cross section of a typical modern glider such as the Schempp-Hirth Duo Discus? How does it compare to a typical GA aircraft such as a Cessna C172 and to a typical airliner such as an jet airliner such as an Embraer E190 and to a typical turboprop such as a De Havilland Canada Dash 8?


texts: Do aircraft technicians need additional certifications to work in other countries?

texts:
Professional technicians, who work in aircraft maintenance, usually obtain some sort of national certification, right?

Let's suppose someone got training and certification in one country, and wants to migrate to another country. Does he require some certification to work there as an aircraft technician? How is it achieved?


texts: How do you calculate the wing moment coefficient knowing the moment at each spanwise station?

texts:
A lot of theoretical formulas exist for finding the moment coefficient for airfoils, but I have been confused by how to get the moments for a wing. I came up with three related questions that have been confusing me a lot:

If I know the moment coefficient at each spanwise station for the wing (so the moment coefficient for each airfoil used along the span), how can I get the moment coefficient for the whole wing? Is it just a weighted integral? If so, what's the formula look like?

How does one find the moment coefficient for a straight tapered wing?

How does one find the moment coefficient for a swept wing?


texts: Learn in-depth about airplane operations

texts:
Currently seeking a book or manual that teaches a civilian how a cargo aircraft operates and what it's pilots do, say a 787. Preferably a high-level overview at a per flight phase:

Pre-flight: Flight planning, aircraft checkout (airworthiness), maintenance checking, taxing, ATC communication, etc
Take-off: What do pilots look at during take-off: engine parameters (torque?), airspeed, etc.
Cruise: What do pilots moderate during cruise? What are they doing to prepare for landing?
Landing: Again, what parameters are they looking at, and how often are they looking down? How and what are they communicating to ATC?
Post-flight: What happens to the aircraft? What maintenance is done on the aircraft? What are they doing while they await instructions from ATC? What reports are looked at.

I understand that this is a lot of information to ask for from one book but I am willing to do a lot of reading, from various sources. Any help in answers these questions would be greatly appreciated as well. Young engineer in the aerospace industry and I'd like to learn more.


texts:
I just got my private pilot license and I want to build-up time with another private pilot

lets say I am acting as a safety pilot and we make a flight of 3.7, and his time under the hood was 3.4 in C172

1-as a safety pilot, what is my total durain time?

2- as a safety pilot, am I going to log PIC, or SIC? and how much?

I keep getting different answers. It would be really appreciated if you cite your source.


texts: Where are the microphones for the black box located in the cockpit?

texts:
All modern commercial airliners have a CVR (Cockpit Voice Recorder) on-board to record what the pilots are saying during the duration for a flight. I feel that the location of the microphones is important because they should be in a place that can easily pick up the cockpit conversations but should also be discreet enough to avoid accidental damage or even intentional sabotage by hijackers/suicidal pilots.

So where are the recording devices or microphones located in the cockpit for this?

Moreover:

Is there more than one microphone in the cockpit to provide stereo sound?
If so, do investigators listen to the recording from each microphone?
Are there any pictures of these microphones in the cockpit?


texts: Why shouldn't variable pitch propellers be operated at low speed?

texts:
Aircraft with variable pitch propellers usually have a red arc on the propeller speed gauge somewhere between about 500 and 1000 rpm, often accompanied by placard like "stabilized propeller operation between 500 rpm and 1000 rpm is prohibited" (the range is slightly different in different aircraft).

What is the reason for this restriction?


texts: How to obtain true altitude from indicated altitude, temperature and QNH?

texts:
maybe it's a little impolite to ask but I got stuck with knowing bunch of formulas and not understanding how to use it:
Can you help me on understanding how the correct answer 7300ft came out of the following question:
Given the following information, what is the true altitude? (rounded to the nearest 50 ft) QNH: 983 hPa;  Altitude: FL 85; Outside Air Temperature: ISA - 10° (1,00 P.)

My attempt based on the fomula from here:

$A_T$ is our estimated true altitude, in feet
$\Delta_{ISA}$ is the difference above ISA, in °C
$A_I$ is our indicated altitude, in feet
$A_{Ik}$ is our indicated altitude, in thousands of feet

$A_T = (4\times A_{Ik} \times \Delta_{ISA}) + A_I$

$A_{Ik} = 8.5$
$\Delta_{ISA} = -10° - ( 15° - (8.5 \times 2) ) = -10° - ( 15° - 17°) = -10° - (-2°) = ISA-8$
$A_i = 8,500$

Therefore,
$A_t = ( 4 \times 8.5 \times (-8) ) + 8,500 = ( 34 \times (-8) ) + 8,500 = -272 + 8500 = 8288$
So my incorrect answer is 8288'. The correct is 7300' :(
I also realize I did not use QNH in my calculations.


texts: What does the preliminary report on the Ethiopian B737 MAX accident show?

texts: In early April the Aircraft Accident Investigation Bureau of Ethiopia released a preliminary report on the crash of Ethiopian Airlines flight 302 that happened on March 10, 2019.  There apparently is some technical detail in it from the "black boxes".  What are some of the main technical things the report shows about the flight?


texts: How is the pressure difference in passenger plane toilets generated?

texts: The toilets on passenger planes flush with an impressive amount of force - Is the negative pressure inside the tanks generated by a pump or are the tanks connected to the outside air pressure? Considering that the toilets should also work on the ground, I presume pumps are used - on the other hand, maybe the low pressure is stored inside the tanks from the last flight? Also, pumps would mean the toilets don't work when the aircraft is not powered up  - is this true? Also, how was the engineering problem solved of keeping the pumps or the tubes connecting to the outside free from waste?


texts: Since engines are run only when the fuel pumps are on and vice versa , why are there separate switches for this? Why can't it be automated ?


texts: Does the Predator drone's design make a tail strike more likely on takeoff and landing?

texts:
I was reading an article about drones and happened to glance at an included 3-view of the General Atomics Predator series UAV. The inverted-V tail appears to leave, at most, around 6" of clearance to the ground.

On takeoff or landing, how is there enough clearance to allow the operator to rotate? Is the wing designed to have a high angle of incidence on the ground?


texts: Do fan blades use bell shaped lift distribution curves?

texts: Seeing the organic curvature of some newer fans in turbofan engines, I'm curious if they use bell shaped lift distribution curves in their design, or something else all together.


texts: Why bother tracking TSN after an overhaul?

texts: I've noticed that mechanics often like to keep track of "time-since-new" (TSN) on components that have already been overhauled.  What would TSN matter when the component is tracked by TSO for maintenance purposes?


texts: Why do airplanes have to retract landing gear?

texts: Why do all the airplanes have to retract their landing gear, once they reach some specific height? Why can't they simply leave their landing gear deployed all through the flight?


texts: Could Falcon 9 fairing become glidable / flyable?

texts:
Reading and thinking about this and this questions on space exploration stackexchange, I was wondering if the fairing could shape itself, so that it becomes one stable and steerable gliding element able to land safely, fully replacing the parachute / paragliding wing.

The idea is to hinge both halves longitudinally, and convert (by actuating & hinging) the tapered conic root part into trailing edge control surfaces or V-tail elevons, making the whole system flyable and steerable, eliminating conflicts between wind, paragliding wing and fairing large surfaces.

Is this concept practical in any way, could this thing fly and if not, why?

(let's assume both halves open for separation with payload, close for entry, open again in "glide mode" once subsonic)


texts: If we enter and exit through the emergency exit, then how come when the door is opened for the air bridge the slide does not inflate?

texts: When we enter through the door it's an emergency door. Right? But if we enter through the emergency door then how come when we open it for the air bridge the slide doesn't inflate?


texts: Why don't aircraft carriers have multiple sets of arresting wires?

texts:
On this answer to this question regarding the merits of angled flightdecks on aircraft carriers, @JanHudec makes this interesting observation:

  You don't really have "two flight decks". The catapults are well distributed, but there is just one set of arresting wires, so while hit to the bow disabling catapults 1 and 2 would leave 3 and 4 available, hit to the landing area still prevents all landings.  [Emphasis added.]

Why don't aircraft carriers have multiple redundant sets of arresting gear, to allow them to land aircraft even if one of the landing runways is disabled by battle damage?


texts: Where is helicopter rotor attached on Allison Model 250 engine?

texts: Which section of the Allison Model 250 engine is attached to helicopter rotor?


texts: Would propellers be more efficient if they were mounted at the rear of the aircraft?

texts:
The propellers of a front-mounted propeller plane push air back directly on a collision course with the aircraft's body. That results in zero thrust or negative thrust from at least some sections of the propeller that are close to the body, thus making the engine work harder and use more fuel as the air bounces back from the body towards the propeller.

Would it not be better to mount single propeller engines somewhere at the back of the plane, where all of the propeller is generating thrust?


texts: I live under Chicago's airspace. One evening I saw a plane approaching Chicago with both wingtip lights red and the front landing lights flashing. I've never seen that before, why would that happen?


texts: Is flying without sunglasses in daylight doable in a Cessna 172?

texts: Do the windows in a 172 provide any protection from the sun or is too bright? Particularly, if one wants to do a flying lesson and was told to bring sunglasses more than once.  So, is it critical?  My friend doesn't have sunglasses and would have to get prescribed ones which he can't get now. He got a gift of a flying lesson so he wants to try it but is being in the plane without sunglasses doable?  Or will he be squinting the entire time? Or is it really bad for your eyes?


texts: How do carbureted and fuel injected engines compare in high altitude?

texts:
I couldn't find enough information on the internet for this topic. What I found can be paraphrased as:

  Carburetor means easy engine start while fuel injected means manual fuel start up and carburetors are cheaper.

So how do carbureted planes compare against the fuel injected ones for GA purposes especially in long distance cold high altitude flights?

I looked for the M-9 Series and the specs doesn't reveal much.


texts: What non-precision approach in the US has the longest segment at MDA?

texts: What approach is the longest approach, in the US, which has the longest segment at the MDA?  Obviously this is for non-precision approaches.


texts:
This question was raised as part of this discussion.

Why are accident rates higher on smaller aircraft?

It seems the safety record of military, private and small commuter planes is much less safe than that of large commercial operations and I was wondering what factors cause this?


texts: Is there a database of airfoils for a given Reynolds number?

texts:
I'm trying  to design my ultralight airplane. I know the basics of aerodynamics and airplane design, however, my question is
if there are any tools (online, software, database ) that suggest the best set of airfoils with best possible Cl/Cd ratio based on a given Reynolds number?

I think that the database  should have all airfoil graph data and not just the geometry information.


texts: What are the differences between FCLP markings and equipment and the LA on a ship?

texts:
Most Naval and Marine Corps Air Stations have these markings on at least one or more of their runways:

It’s a Field Carrier Landing Practice (FCLP) area and used to maintain proficiency amongst carrier based fixed wing squadrons with landing in a carrier.

The area is marked like the Landing Area (LA) on a carrier.  However, since the real carrier is steaming forward at 25-30 kts during recoveries, the perception of the pilot approaching the real LA will be a little different than when approaching the FCLP area.

Approaching a carrier with an LA angled 9° left of the ship’s keel axis requires not only that the pilot crab to the right on approach but the closure with the touchdown area, when at optimal AoA will be 25-30kts slower at the boat than when doing FCLP approaches.

I’m wondering if the Navy has modified these FCLP area making them elongated, decreasing the glideslope angle in the IFLOLS, etc. to more realistically simulate an approach to a carrier during FCLP workouts.


texts: Where can a realtime map showing all flights and all dangerous areas be found?

texts:
Further to my other question, how can I find a realtime map of all flights that's combined with the foregoing map of all perilous zones? My goal is to see which flights may be overflying them, and in particular, if there are any commercial flights doing so.

For example, I only learnt of this via CNN, but want to predetermine this by myself: http://edition.cnn.com/2014/07/22/world/asia/malaysia-airlines-plane-over-syria/


texts: What are the differences between these types of air cycle machines?

texts:
I am MSC student of mechanical engineering and my project is about ACM machine. I have read something about various systems of air conditioning system in aircrafts;

simple system
boot strap
reduced ambient temperature
regenerative system
boot strap with evaporator
simple system with evaporator

I just know that reduced ambient temperature is for supersonic aircraft.I don't know other systems applications.For example, when is a regenerative system used and when boot strap is used?

Are all of the possible air conditioning systems exists in every aircraft and switch to another depending on flight condition?


texts:
Recently someone on another thread recommended the following video:

Andrew Godwin - What can programmers learn from pilots? - PyCon 2015

where the speaker, at about ~3:14, talking about pilots mentions:

  not to the point where we can replace them with computers, because we're not there yet

which got me thinking:

How close are we to replacing pilots with computers? (like totally)


texts: At what altitude do vacuum powered gyros become ineffective?

texts:
Obviously, in space a vacuum powered gyro would not work because there is no air to move, but, how high do you have to go before they are unable to spin fast enough to work properly?

would a vacuum gyro work properly in a sr71 at 80,000 feet?


texts: Does ATC direct flights to fly eastbound at odd levels and westbound at even ones?

texts: Do commercial airlines routinely travel at altitudes specified by the ATC based on the direction they are heading? Example: eastbound flights travel at odd levels and westbound flights travel at even ones?


texts: Reference Map of EUROCONTROL charging zones

texts:
I'm building out an application to calculate EUROCONTROL navigation fees. EUROCONTROL make one of these already, but I need to replicate the functionality within my own stack.

In the aforementioned EUROCONTROL app, there is a data file containing what appears data in a geospatial format. In order to do the required calculations, I first need to understand that data format.

My first impression is the first row is some metadata. EG means the UK. From there the number pairs begin and end the same, indicating a closed polygon.

Example for EG (so UK) is here

3274 -600
3300 -600
3360 -600
3420 -600
3480 -600
3540 -600
3600 -600
3660 -600
3660 -540
3660 -484
3660 -480
3660 -420
3660 -390
3660 -360
3660 -300
3660 -275
3660 -240
3660 -180
3660 -120
3660 -111
3660 -60
3655 0
3600 0
3420 300
3300 300
3090 120
3067 120
3060 88
3040 88
3000 -15
3000 -120
2930 -480
2940 -480
2970 -480
3000 -480
3060 -480
3140 -330
3235 -330
3265 -490
3320 -415
3325 -440
3320 -495
3285 -540
3274 -600

Plotting the numbers in an SVG, so simply turning the numbers into pixels gets me this...

I'm hoping that matches a EUROCONTROL map someplace. Geospatial data  can be quite complex, and I don't really understand a lot of that complexity, so projection might be off (or any number of other things).

Can anyone point me in the direction of this within an official EUROCONTROL document? From there its a short hop to understanding how that original data file can be translated into some GIS software that gets me to the next stage of my project.


texts: Are directional instruments like an HSI or AHRS immune to magnetic compass error?

texts:
Pilot educational curriculum includes learning about magnetic compass errors intrinsic to their construction.

A standard magnetic compass in an airplane erroneously shows turns when accelerating or decelerating on an east or west heading. They also read incorrectly during turns from the north or the south.

My question is about more advanced instruments like a fluxgate compass found slaved to an HSI or a magnetometer used in an AHRS. Are these systems impervious to the compass errors present in a magnetic compass?


texts: Can I use motor oil in a aircraft piston engine?

texts: In one episode of the 'reality' show Airplane Repo a pilot topped off an aircraft engine with motor oil; I think it was a Cessna 182 but I may be wrong. What would be the effect on the engine? Is it a practical (and safe) alternative if aviation oil isn't available?


texts: Can military personnel land their own private aircraft at military bases?

texts:
First off, I am asking similar, but logistically different question to What process do I follow to land a civilian aircraft on a military base?

If I am in the US Military (with a valid ID), am I free to land my personal (civilian style) airplane (with my civilian licence) at military bases - in the same sense that I could drive my car on?


texts: Can I fly in Europe using an FAA Statement of Demonstrated Ability (SODA)?

texts:
I want to become a airline pilot but I have Monocular vision. I have no vision in my left eye but I have good vision in my right eye. I have read that I cannot become a pilot in Europe because of this condition.

So I just want to know if I can get a Statement of Demonstrated Ability (SODA) equivalent in Europe and then become a airline pilot?

If that is not possible, then can I take an FAA medical class 1 with a SODA, and then move back to Europe and fly in European airspace and fly internationally?


texts: What is the extra cost of aborted landing and go-around for typical "big" airliner?


texts: Can we use the term CONTAMINATED RUNWAY for other meanings, such as: oil spill or debris on the runway?

texts: Contaminated Runway is used to say that the runway surface area (25%) is covered by 3.0 mm or more of: water, slush, snow and ice. But is it also possible to use this term to say about: heavy rubber, oil spill, debris or other substances are on the runway surface?


texts: How much does a new hangar at a major airport save an airline?

texts:
I'm doing research on a case involving United Airlines trying to build a new hangar at Newark International Airport, and being extorted by the chairman of the Port Authority. He demanded an unprofitable, bi-weekly custom flight route in exchange for his approval.

As a small but important detail of my research, I'm trying to determine how much an airline can save by building a new hangar at a major airport.

I believe the primary benefit of a new hangar is the ability to do repairs and maintenance locally, instead of having to fly the plane elsewhere to do it. Is this true?

What expenses, roughly speaking, does a new hangar of this sort save a major airline each year (or longer period)? Sources would be appreciated.  So far I've only found information on the benefits to private plane owners in using or renting hangars.


texts: How does the F-16 side stick convert pilot input to an electrical signal?

texts:
In What is the motivation behind designing a control stick that does not move?
the F-16's control stick is discussed. What is the method that is used to sense the pilot's input to the stick and convert this to an electrical signal?


texts: What does the "D" symbol mean on this instrument approach chart?

texts: What does the "D" symbol mean on this approach plate in the airport diagram section (bottom left of plate)?


texts:
Why are geodesic airframes no longer produced?  Do they cost more than conventional structures?  Are they not as strong as conventional structures?  I assume it is insufficient cost benefit ratio, but how does that work out?

  Wellingtons under construction. Photo: Royal Air Force


texts:
I'm working through the ASA Private Pilot 2020 Test Prep questions and there's a question I don't understand the answer for.

3579 (Refer to Figure 28, illustration 5) The VOR receiver has the
indication shown. What radial is the aircraft crossing?

A - 030
B - 210
C - 300

I thought the answer was B - 210 but that is the heading, not the crossing.
The correct answer is A - 030, but I'm not sure why. What does it mean to be crossing a radial?


texts: How does the canard plan of the Dassault Rafale work?

texts:
I'm quite puzzled after seeing some videos of the Dassault Rafale. When pulling the stick, the canard plan should move as in this video (low speed, high angle of attack, stick pulled backward on average). But, this a high load and high speed maneuver, the canard plan's position should be similar but it is not.

How is that possible? Does the canard plan act as a canard plan only at low speed, the elevon doing most of the job at high speed?

I'm double puzzled as this canard behaviour seems to be the same for the SU-30.


texts: What is the regular stall speed of an F-16 flying in a straight-and-level path?

texts:
I want to know what is the minimum speed that an F-16 can fly at without stalling.
I have searched the web, but found no exact information answering my question.
Most of them say that it depends on many factors, like payload and maneuvering. But, for simplicity, I want to know the stall speed of that plane flying in a straight path at a constant altitude.

If there is no exact answer, I want to know the regular stall speed, just an average value of that speed, for a clean F-16A weighing 18,000 kg flying in a straight & level path.


texts: Can a modified aircraft be imported and certified in the US?

texts:
Aircraft can be brought into the US and be made airworthy by FAA standards. What about aircraft legally modified in other countries?

For example, there is a new STC to put a Rotax 912 into Cessna 150s approved by the EASA. Can that STC be made legal in the US even though no similar STC exists here?

If yes, is this just due to relations between the EASA and FAA, or can this be done with aircraft coming from anywhere?


texts: How is the area rule applied on airliners like the A380?

texts:
Wikipedia says that because of the area rule's impact on wave drag:

  aircraft have to be carefully arranged so that at the location of the wing, the fuselage is narrowed or "waisted", so that the total area doesn't change much.

This much makes sense to me. Though it's a bit difficult to tell, I understand that in the picture supplied there, the green circle toward the front of the aircraft is intended to have roughly the same area as the blue circle and lines through the wing cross-section:

All images from Wikipedia unless otherwise noted

This is more clear in the picture of the F-106 Delta Dart where one can easily see the Coke bottle waist where the wings near their widest:

That's an awesome picture! You could stare at it all day, couldn't you?

Peter Kämpf even provides a nice explanation of the area rule in his answer here including a drawing from the Junkers patent on the subject:

Image posted by Peter in his answer, referenced above

In this image, I can see how the areas through several lines across the fuselage, wings & engines are all intended to be (roughly) equal.

What I don't understand is how this is applied to airliners like the Airbus A380 which they say is:

  showing obvious area rule shaping at the wing root

in reference to this image:

To me, it appears that the cross-section at the wing root consists of the same area at the front of the plane (roughly behind the cockpit appears to be where maximum diameter is achieved), plus the area of the wing root, plus the area through the wing, plus the area through a pair of engines (depending on exactly where you make the cross section). As I see it, there's no slimming of the body to make the area through the wing cross section equal to the area of the cross section just behind the cockpit.

This shot from above of another A380 shows that there is no Coke bottle waist near the wings:

Am I not seeing this correctly, or do I not understand the area rule correctly?


texts: How does ATC handle different kinds of emergencies?

texts:
This question deals with the pilot procedures for declaring an emergency.

I wonder how ATC in the US handles different kinds of emergency or quasi-emergency situations, such as:

MAYDAY
PAN PAN
Minimum Fuel
Medivac
etc

Are there multiple levels of priority handling inside ATC, and how do they communicate priority handling from controller to controller?


texts: In terms of noise, how does a steep climb-out compare to a noise abatement procedure?

texts:
For airports in populated areas, it is common to implement noise abatement procedures. In practice, this means that aircraft reduce thrust on departure, so that noise is reduced in proximity to the airport.

However, this does mean that aircraft spend a longer time at a lower altitude, which may be bad news for populated areas further away from the airport. I am wondering how noise abatement procedures affect areas further away, up to 150km away from the airport. I would like to know how this compares quantitatively (e.g., a dB(A) chart like below, for larger distances) between procedures.

Image: Hamamci et al. (2017). Determining characteristics of lands affected by noise pollution of airports. Fresenius Environmental Bulletin. 26. 69-74.