texts: Is co-flow jet wing technology workable?

texts:
Coflow Jet claims that their idea of sucking air from the trailing edge and blowing it out the leading edge improves efficiency.
But this looks like nothing but flow control done wrong to me. And by blowing at the leading edge, they give up on achieving laminar flow(!).
They also claim that it increases transonic efficiency.
Does this work?


texts: Lost radio communication after take-off in IMC - what are my options?

texts:
This might be "yet another lost comms questions", but I've tried to read a lot and there are different answers everywhere. Here's the scenario:

(The flight plan as filed is - KSSI SSI V441 MONIA GNV OCF V581 DADES KTPA)

I'm taking off from an uncontrolled airport - KSSI to fly to KTPA (ICAO IDs). The current weather at KSSI is 003 OVC and 2 SM. I call MACON FSS for my clearance on 121.5, and here's what I get -

MACON FSS: "ATC clears N123CW to KTPA Direct SSI and then as filed, climb and maintain 4000 expect 8000 two-zero minutes after departure, departure control will be 126.75, squawk 1234. Released for departure, clearance void if not off by 20:45, time now 20:30, frequency change to advisory approved."

After read back, I take off exactly at 20:35 and after a couple minutes I contact Jax Center on 126.75 as I'm crossing 1300ft. I hear no other traffic on the frequency, and I try to contact them 2 more times while I'm heading direct to the SSI VOR. I try to contact MACON FSS with whom I'd just spoken a few minutes ago - and I hear nothing back. I try a couple of other frequencies that I can get from charts - no luck anywhere. I'm in complete IMC.

Now, I know that I've lost my radio communications capabilities and hence squawk 7600, and figure out my route and altitude to fly.

I was cleared direct to the SSI VOR, and then as filed. Looking at "AVEF", ATC expects me to fly the route I filed. Looks good - no problems here.

I was asked to climb and maintain 4000ft, and expect 8000ft 20mins after departure.

Looking at "MEA", ATC expects me to be at 8000ft since it's the highest amongst the Minimum En-route Altitude, the expected altitude (which is n/a) and the assigned altitude).

I'm still at 2400ft, climbing to 4000ft.

My questions are:

1) When should I start my climb to 8000ft? Should I level off at 4000ft and wait until 20:55 (which is 20 minutes after my departure time) before initiating my climb, or does ATC expect me to be at 8000ft by 20:55?

2) Along my route (not immediately after departure, but after a while), for e.g. at the GNV VOR, if I briefly enter VMC, should I go ahead and land at the nearest airport as practicable or should I still continue through my route? I do know that the regulations advise to land as practicable when you're in VMC, but if the airspace ahead is being cleared for you when you're under IFR, is it advised to try and land into VFR traffic who have no idea that you're coming-in out of nowhere?

Appreciate all the answers. Thank you!

PS - Here's the Low-Enroute chart for quick reference:


texts:
In view of this other question, does the lead first enter or infiltrate the cabin air dispersion system, and then pervade or permeate the entire passenger cabin, thus every breathing passenger?

I believe that the recirculated cabin air passes through HEPA filters, but does this resolve all the menaces and perils of lead? If not, how can passengers protect themselves?


texts: For general aviation small aircraft flying VFR under 10,000 feet, can I use my phone GPS for navigation in the US?  So no onboard GPS (which are expensive), no VOR/DME, of course there is always dead reckoning and pilotage.


texts: Why are holding patterns clockwise by default?

texts:
PANS-OPS (Doc 8168), Procedures for Air Navigation Services, volume 2, section 4, chapter 1: "If no operational considerations prevail, right turns holding patterns should be established."
When was this convention established, and why?


texts: Where can I obtain official German VFR approach charts?

texts: I am looking for the official VFR approach charts of German airports. I could found a preview here : airports.de however I do not know where I can find the official ones or where I can order them. This would be useful to purchase the  maps only for the  airports I am interested. Any suggestion?


texts: Is a Mooney M20 a difficult plane to fly as a beginner?

texts:
I am considering purchasing a Mooney M20 for 60k to fly for my initial certification. I'm not sure if this seems like a logical choice on the surface but let me explain my reasoning. I travel quite a bit. I live in the Dallas area and drive to Houston, Austin and San Antonio regularly. I average 60 hrs in the car a month traveling. This aircraft would be used for travel on a regular basis, 15-20hrs a month. The speed of the mooney is what is most attractive to me. I considered a 172 but the faster Mooney will save me valuable travel time. I will occasionally have 2-3 passengers with me.

My questions are:

Am I crazy?
Is a Mooney a difficult aircraft to learn in?
Should I suck it up and pay the rental fees and buy the Mooney after I get my license?


texts: What restrictions apply to flying RC and UAV planes in India at very low altitudes?

texts:
We are working on a UAV and will soon get to the testing phase. We intend to fly at a maximum altitude of 300-400 meters. I wanted to know as to what restrictions apply to the airspace in India (specifically Delhi) with respect to flying UAVs as well as the altitudes from which they apply?

We will also be testing autonomous capabilities. Do we need to get any licenses for this?


texts:
In flight training we're warned against skidding turns since they have a higher potential for a stall/spin (the classic example being the stall/spin on the base to final turn).

However, how does the airplane behave during a stall entered from a slip?

It's a cross-controlled condition, but since the rudder input is opposite to what it would be in a skid, is it more difficult, or not possible, to spin from such a situation?


texts: Which aircraft can fly at FL600 or above?

texts:
I would like to know some examples of aircraft (specific models) which can fly at FL600 or higher.

I am interested in aircraft which can or could fly at that altitude on a regular basis (service ceiling included). Space exploration or launcher systems are out of the scope.

As far as I know, commercial airplanes cannot fly that high so I can only think of jet fighters, aerostatic balloons, and rocket-powered aircraft.


texts: Finding Angle of Attack/Angle of Sideslip using East/North/Up Coordinates

texts:
I've got a set of data that includes:

x rate, y rate, z rate (all ENU) which I'll call xd, yd, zd.
roll, pitch, yaw (which I'll call ϕ, θ, ψ)
roll rates, pitch rates, yaw rates

I'm looking at some math that is meant to convert these values to AoA and AoS, but I'm having trouble understanding exactly what's going on.

As far as I'm aware, this is basically just taking euler angles and making a rotation matrix and using that to find u,v,w. But I'm having trouble verifying the accuracy of this work (it was done by someone who is no longer with the program.)


texts: How do aircraft manufacturers determine the elevator size?

texts:
I’ve heard some pilots say the MD-11 (I think?)was made with too much elevator, and that it’s an overkill.

So now I’m curious, how do they determine the length for the elevator? Is it possible to make one that can be called an “overkill” without it having drastic effects on the flight?


texts: Why didn’t the 757 have manual-reversion capability?

texts:
The Boeing 757 was the highest-capacity and latest-designed narrowbody Boeing ever produced (and, in the case of the 757-300, the highest-capacity narrowbody anyone ever produced); it was also the only Boeing narrowbody lacking any form of manual-reversion capability for its flight controls in the event of a total hydraulic failure.

Now, I can sort of see why Boeing didn’t bother to give their widebodies manual-reversion capability (even if I don’t agree with their reasoning on that point), but the 757 is just a large narrowbody, and not even Boeing's largest; the 707 was even heavier (123,830 kg MTOW for the 757-300, versus 151,500 kg for the 707-320B/C), and it had full manual backups for its flight controls.  Also, in the time since they decided to leave manual reversion out of the 757, they’ve grown the 737 to near-757 size, and yet haven’t had any trouble at all keeping its manual-reversion system working!

Besides, if our friends beyond the Iron Curtain could do it all the way back in the 1960s (MTOW 165,000 kg)...

The only reason I can see that would sort of make even a bit of sense (if you scrunch up your eyes and look at it in a certain very-specific sort of way) would be if they left it out in order to avoid introducing excessive differences between the piloting skills required for the 757 and those required for the (widebody, and, thus, reversion-free) 767, and thereby possibly jeopardising the common type rating pilots can obtain for the two - but how can operational convenience possibly justify skimping on safety?

Why did Boeing leave manual-reversion capability out of the 757?


texts: Why do BWB designs typically put the engines in the rear?

texts:
A Blended Wing Body aircraft looks something like this:

In fact, every true BWB concept model I've seen puts the engines in the rear. Why is this? Can't they be hanging from the wings on pylons?

I'm envisioning a large cargo aircraft, if that maters. In fact I'm considering turboprop engines for even better fuel efficiency, so you could theoretically put one of them on the nose.

Is there something about BWB geometry that greatly favors rear engines? Wikipedia says the body can generate its own lift. Does that mean the airflow is faster over the top and therefore you get greater intake mass flow at the top of the tail area?


texts: Would a rotating skin design mitigate the heating problem limiting hypersonic flight?

texts:
Would a rotating skin design - where the skin of the aircraft rotates (powered either by an electric motor or the colluding wind) - mitigate the heating problem limiting hypersonic flight?

Would a liquid cooling system (to cool the skin as it rotates along the aircraft) add additional benefit?


texts: Does the explanation of why slower airfoils are more efficient involve less energy loss from heating or compression of the working fluid?

texts:
We read time and time again, how more efficient slower airfoils such as helicopter rotors, props, and sailplane wings are compared with rapidly rotating fan blades or faster (still subsonic wings).  We also read where some people consider compression a negligible factor below a certain speed, even to the point of considering airflow < 200 mph as "incompressible"!

Yet looking at this commonplace and ubiquitous phenomena (indeed, while your prop is putting out 600 lbs of thrust, your wing is creating 4x more lifting force), is there a mathematical explanation for this involving the ideal gas law:  PV=nRT?

Can we visualize creating and maintaining a compressed "bow wave" ahead of a moving surface involves substantial amounts of energy even at lower speeds?

I have yet to fully understand why "it is better to move a lot of air a little than a little air a lot".


texts: What is the measurement system used in the aviation industry?

texts:
I saw this question from History Stack Exchange and noted that the US is still using the imperial measurement system such as feet, miles and pounds.

Given that a plane may need to fly from one country to another, is there any standardisation across the globe? Does planes manufactured by Boeing use one system and planes made by the Airbus another system? If not, wouldn't it be very easy for pilots to make calculation error?


texts: When was trim on airplanes used for the first time?

texts: I would like to know when trim control was set for the first time on airplanes.. thank you!


texts: Why does flight training usually start with (unsafe?) propeller planes and not with (safer?) jets?

texts:
I live in the UK and would like to learn flying jets, but most courses seem to start with propeller planes.
Not sure if this might be a misconception about the safety of different aircraft types, but I remember having read or heard somewhere that small propeller planes are, well, less safe than jets; maybe because they are more fragile and less powerful than jets when it comes to bad weather and are also difficult to recover from dangerous situations... not sure and cannot find the reference for now.

But also doing a quick search for popular aircraft types, the propellers like Cessna seem to have huge numbers of crashes/incidents compared to jet engine aircraft.

So the question is - why are propeller planes favored in training e.g. for the Private Pilot License? Is it simply because they are cheaper and wouldn't be such a huge loss of they crash?

Are there any alternatives where I could start with a jet engine?


texts: What are the advantages and disadvantages of level flight with a nose-down attitude?

texts:
This is a questions about fixed-wing aircraft in general -- commercial planes and smaller. I have seen on a video that planes are capable of flying in a holding pattern with an nose-down attitude "for greater passenger comfort".

So, what are the advantages and disadvantages of level flight (not descent) with a nose down attitude?

And for what reasons do pilots fly like this?


texts: Why the "Terminal" in Terminal Aerodrome Forecast?

texts: Why isn't it just called Aerodrome Forecast? Where does the "terminal" part come from?


texts: Did the F-8 have a stall speed of 1.6x its landing speed?

texts:
Wikipedia says that the F-8 was to have

  a landing speed of no more than 100 mph (160 km/h)

This web page says that the F-8 did have

  Stalling speed 157 mph.

The two don't explicitly discuss exactly the same thing, but I do note that e.g. the quoted cruise speed of 570 mph agrees on both. Unfortunately, neither page seems to specify the actual landing speed of the final aircraft.

From an aerodynamics perspective, this doesn't really make sense to me: it seems awfully difficult, to not say outright impossible, to have a stall speed that is significantly higher than the landing speed. Intuitively, the two should be just about the same, or the landing speed should be higher than the stall speed.

Did the F-8 actually have a stall speed of around 1.6 times its landing speed as suggested?
Is that even possible?
What were the stall and landing speeds of the F-8?


texts: Why do I missing 1090 Rebroadcast Traffic (ADS-R) Targets from Ground Station as part of 978 Uplink?

texts:
For context I have an ADS-B 1090 OUT and 978 IN. I also have a Stratus portable Dual channel receiver in my plane, so I have the option of comparing the traffic between systems.

What I’ve been noticing is that lots of 1090 targets that I can see on Stratus connected iPad, I can never ever see it on my display connected to 978 IN avionics. My understanding is that my setup should:

A) Receive direct reports from aircraft equipped with UAT/978 OUT hardware. (Air-to-Air) (Working Good)

B) Receive ADS-R rebroadcast traffic from ground stations, for 1090 targets. (Not receiving)

C) Receive TIS-B traffic from ground stations, for Mode-C targets that aren’t participating in ADS-B network. (Good)

So my question is, why do scenario B seem not to be working for me?

I pulled ADS-B Performance Report for my flights and I see:

OUT capability is correctly listed as 1090 and IN capability is listed as UAT. This should indicate the Ground Stations that I need 1090 targets as part of rebroadcast (ADS-R) to me. I contacted FAA on it and they agree too

Any thoughts? is it something I am missing in the ADS-B OUT configurations or could it be Ground Station issue?


texts: How do I know my AGL altitude while in flight?

texts:
I am about to start my PPL, still flying in my FSX.

I have a question, let's say I am flying from airport A to airport B. Both airports are in G airspace and I would like to stay in G airspace and don't go over 1200' AGL to class E. Let's say I would like to fly at 1100' AGL and keep this altitude from A to B. And let's assume we are in un-congested area, so we do not violate minimum safe altitude rule. But I do not understand if terrain in uneven, I mean its elevation is constantly changing, how do I keep my altitude 1100' AGL. I don't have radio altimeter like in Boeing. I understand that at the airport you can get your elevation, also you can have minimum safe altitude from sectional chart and also you can find any obstructions, but how do I know in a middle of my flight (if I need to).

If this question sound stupid and pilot don't fly in G airspace please let me know.


texts: When were the last subsonic turbojet-powered airliners retired from commercial passenger service?

texts:
The very first jetliners (Comet, Tu-104, Caravelle I-VI, 707-120/-220/-320, DC-8 series 10-30, original 720, CV-880) all used turbojet engines, turbofans not being available until later; when turbofans became a viable option, jetliner manufacturers switched over to turbofans en masse for their new designs (including the later versions of the Caravelle, 707/720, and DC-8), and some of the older, turbojet-powered airliners were converted to also use turbofans, but many already-built jetliners continued to fly under turbojet power for decades.

I have been unable to ascertain precisely how long subsonic1 turbojet-powered airliners continued to carry paying passengers in regular service.  Wikipedia says that the Tu-104 was withdrawn from passenger service in March 1979, and the Comet last carried paying passengers in 1981, but does not provide a citation for either statement, and I have been unable to find any information as to when the other turbojetliners were retired from passenger service.

Can someone help with this?

Yes, I am aware that the Concorde used turbojets; it does not count for the purposes of this question, as it was a supersonic aircraft, cruising at Mach 2, where turbojets are actually more efficient than turbofans, whereas this question concerns those early subsonic aircraft that were only built with turbojets because turbofans were not yet an option.

EDIT: The original intent of this question was to ask when the last subsonic turbojetliners in scheduled passenger service anywhere in the world were retired, but John K's comment raises the good point that these aircraft would have hung on in the dusty corners of the globe for a good long while after they were retired in places like the U.S. or western Europe.  Therefore:

When were paying passengers last flown in scheduled service on subsonic turbojet-powered airliners...

...in First and Second World countries (U.S., Canada, Europe, East Asia, Australasia)?
...anywhere in the world?

EDIT 2: The Trident 3B also does not count, as it was mostly turbofan-powered, using the turbojet only as an additional booster on takeoff for hot-and-high operations.


texts:
I have been sent some old intermediate Royal Navy exam papers from 1956, I took a similar exam in 1966. One question concerns Wing Loading in a vertical loop, i,e, at the top and bottom. I know the weight, radius, speed (remains constant) and wing area. Units are British Imperial. In the deep recesses of my mind I remember that:
W=L= Clrv^s where r is density in straight and level flight.
Question
what other factors or formulae do I need produce an answer.


texts: Is there a system where plane/heli auto adjusts prop pitch/mixture?

texts:
This one is simple: is there a system that automatically adjusts things such as:

Mixture (I Am bored of listening for engine sounds)
Prop Pitch (I Hate auto adjusting "gears")

So I can only spend time adjusting throttle ?


texts: How does one become an airline pilot in Australia?

texts:
I am 19 years old and from a young age I have always wanted to become a pilot at an airline. Becoming one is my biggest dream, to me an airline pilot is the most coolest jobs - I get goosebumps just by thinking about me in that position.

I have finished my high school education and hope to go to Australia to study in order to become a pilot. However, most of the university programs don't give me the feeling that I can become a pilot. Most of what is learned and practiced is in small planes, even the career opportunities don't mention that one will become an airline pilot.

Does anyone know the best and fastest way to make my dream come true? What should I do?

The only course that has got me attracted to is the one that's in Swinburne University, but then again, small planes. I am fine with flying small planes, but where does that big jump to airplanes happen, if it's not taught in university. Where do I learn it? Does anyone know the procedure or the best place to train to become a pilot?

Also, I'm not an Australian so I will be an international student. I have checked for jobs in my home country airlines, they require a minimum of 5000 hours of flight, does this mean normal plane flight hours? Where will I get these hours covered from? Of course this many hours aren't offered in university.


texts:
What is the best way to keep logbook entries backed up?

Should a photocopied or scanned image on a computer suffice? Can an Excel spreadsheet or other software/apps be used? In case a logbook is lost or (unfortunately) destroyed, should all entries from the backup be rewritten in a new logbook?

Also, when one has 100s or 1000s of hours, spreading over several logbooks, how much importance the older logbooks will have? Would someone go over every page to make sure that this individual actually have 1375.2 hours (as an example)?


texts: How are spacecraft and aircraft traffic coordinated?

texts:
From time to time spacecraft cross our atmosphere, either climbing to space or returning from space. While the probability for a collision is tiny, it is certainly not null, especially during reentry, when the trajectory is not vertical and can cover hundreds of kilometers at aircraft altitudes.

Is there any coordination to prevent collisions between spacecraft and aircraft?


texts: Is failure to comply with evacuation procedures illegal?

texts:
In every flight, we are instructed that we must leave our personal belongings in case of evacuation. I remember also notified that it is illegal not to follow the rules (I don't remember if this goes only for the non-smoking rule though).

So, is it "illegal" to take your stuff with you, while instructed to leave the airplane in an emergency (thus stalling the process)?


texts:
The pilots operating manual of our Cessna 182 contains the lift-versus-alpha and lift-versus-drag data of the airplane, so I assume this is data that should be publicly available.

Is there a trustworthy resource where I can get the polar curves of different aircraft, especially airliners? I'm looking for that of the Airbus A350 XWB in particular.


texts:
I'm not a professional pilot, just an enthusiast, so this might seem obvious to others; but I noticed that airports don't use sequential numbering for runways, starting from 1.

Liverpool (for example) has runway 9/27; so how are these numbers assigned? Also, what do Left and Right signify?


texts: Why would a stretch variant need a larger horizontal stabilizer?

texts:
With the 787-10 stretch, Vedad Mahmulyin (a Boeing engineer) saved the company millions by implementing a software solution that negated the need to enlarge the horizontal stabilizer.

Software again proved useful with the sizing of the horizontal tails. As a stretch of the 787-9, textbook aircraft design would suggest the 787-10 would need larger horizontal stabilisers, offsetting the effect of the longer fuselage on pitch control. Instead, Boeing engineer Vedad Mahmulyin used software to increase the effectiveness of the existing stabilisers. Boeing gave Mahmulyin an internal engineering award for solving the problem.
Flight International (27 Mar 2018)

When a plane is shrunk, that is usually the case because of the reduced moment arm. When it is stretched, the tail volume is retained if I understand this comment about the DC-10/MD-11 stretch correctly:

Isn't the tail of the MD-11 smaller because it has a longer lever arm? The tail volume of both aircraft should be quite the same. Also, any FCS cannot help to trim the aircraft over a wide range of cg positions, and it is this trim range which drives tail surface volume. @PeterKämpf

So why would a stretch variant need a larger horizontal stabilizer?
Also, from an interview with Mahmulyin:

Mahmulyin figured out he could use software to tell the wings and the stabilizers how to fly together, "As opposed to having to produce all new horizontal and vertical stabilizers," he said.

What does "flying together" mean? (This is an optional question and does not involve proprietary information.)
Update and accept reason
The reason for asking why would as opposed to why does is I was not aware of any previous [jetliner] stretch requiring a larger horizontal stabilizer. For example, all the DC-8's from shortest to longest (almost the same stretch as the 787-10) retained the horizontal stabilizer throughout:

Source: Great Airliners; click to view

But then I finally recalled a situation where it has happened, the 737 Classic, and the reason given is the "fore-and-aft loading flexibility", in other words the cg range, and that's why I'm accepting @jwzumwalt's answer.


texts:
Can anyone cite any regulation that would prevent my child (not infant) from logging time for a private pilots license (i.e. 12 years from now when they are 16 for a solo, 13 years for a license when they are 17)?
Background: I have children that I would like to start instructing and having them log flight training when they fly with me. I am VFR/IFR and medically current, and have a current FAA flight instructors license, therefore my question doesn't involve my own qualifications. Just if there are any known restrictions against the kid logging flight time. To clarify I don't mean both kids logging time on the same flight, just one kid.
I have found none in the CFRs (e.g. 61).


texts: How do general aviation airports inspect their runways?

texts: How do general aviation airports inspect their runways for cracks, ruts, holes or anything that would impair their integrity?  How often do airport operators conduct standard inspections of their runways as well as taxiways and ramp areas?


texts: Why does the bottom part of an aircraft nose curve upwards?

texts: As you can see in this picture the bottom of the fuselage curves upwards to form the nose.


texts: Did Flight Engineers progress to be pilots?

texts:
When 3 man cockpits were common place on commercial aircraft what was the career progression of a Flight Engineer like?

Did FE's normally transition to be pilots? I'm not trying to insinuate here that FE's were in anyway inferior to the pilots and of course some FE's would of had no desire to transition to a pilot capacity at all.

Were there any airlines who operated a policy of starting flight crew out as a FE then training them as pilots?

N.B - Some background information that I'm basing this question on is I've read a number of reports regarding young (early 20 y/o FE's becoming pilots) and in maybe a more extreme case the hijacking of FedEx Flight 705 when the FE who hijacked the aircraft (an ex-Naxy pilot) had been made a FE (this could be part due to the fact he apparently falsified his Navy flying hours).


texts: What is this plastic device inside the plane window?

texts: I saw this on a recent domestic flight. It was glued on all the windows of the plane, behind the first layer of plastic. What is it and its purpose?


texts: May a non-instrument pilot legally file IFR as long as he amends and doesn’t accept an instrument clearance?

texts:
Say a pilot plans to make a cross country flight along Victor airways, but under VFR. Depending on workload and communication effectiveness along the way, our hero may provide the planned fairly complex route to the FAA at least three times.

Flight Service Station
Tower, if departing from such an airport
Approach/Departure Control or ARTCC

This seems like needless frequency congestion. Our hero happens across a suggestion from an ATC specialist that appears to solve the problem for everyone, emphasis in the original.

  If you file an IFR flight plan through any system, I will receive it. Make it clear to the first controller you contact that you want to fly your filed route as VFR and give the altitude. It is a very simple amendment I will be happy to make. The only difference on my flight strip is the altitude block that says 60 for IFR or VFR/65 for VFR, and a V in your data block on my radar scope. If you do this, do not accept an IFR clearance. If a controller says cleared to any fix, that is an IFR clearance. Using this method, everything on my end will work smoothly whether you depart a towered or nontowered airport, and this would be the easiest method for the controllers involved. CAVEAT: I do not know if it is legal for a non-IFR rated pilot to file an IFR flight plan even if you don’t accept an IFR clearance.

May a pilot lacking an instrument rating or currency legally do so?


texts: Why do engine cowl lips appear larger and more blunt on the sides than on the top and bottom?

texts:
I was looking into engine nacelles. I was not able to understand the design shape of it

Why is it that in most aircraft, the engine cowl lips on the side are bigger (more blunt) than on the top and bottom.


texts:
I want to know what is the difference between slats and flaps and the mechanism of the slats

This what I know and researched about flaps:

Flaps are a kind of high-lift device used to reduce the stalling speed of an aircraft wing at a given weight. Flaps are usually mounted on the wing trailing edges of a fixed-wing aircraft. Flaps are used to reduce the take-off distance and the landing distance. Flaps also cause an increase in drag so they are retracted when not needed.

This is picture of slats in real life

Flaps on a plane

Once again, I want to know the function of the slats and the difference between flaps and slats.


texts: What are these accelerating flare countermeasures called?

texts:
There seems to be a type of flare countermeasure, that not only gets ejected from the flare dispenser, but also gets accelerated in the direction of the plane. So fare I´ve only noticed it on super and legacy Hornets.
My question is, whether anybody knows the actual name for those kinds of flares, and if there is any kind of information on how they work.

Video of legacy Hornet dispensing a normal and an accelerating flare

On the left Hornet you can see one of the two flares accelerating forward in a spiral after it is out of the dispenser.

Video of super Hornet dispensing a normal and an accelerating flare


texts: How do pilots and controllers deal with TFR's that lie directly on an approach?

texts: FDC Notam 4/3621 creates a generic "template" TFR which sits on top of sporting events.  This one in Phonenix appears to sit right on one of the business ends of Phoenix Sky Harbor (PHX)  The Notam states that event operations are permitted with the appropriate waiver.  How do regularly scheduled airlines deal with such TFR's?  Are waivers obtained for scheduled inbound flights?  There does not seem to be verbage in the notam granting any exceptions for air carriers.


texts: Is the hydraulic fluid artificially colored?

texts:
A normal aircraft has multiple hydraulic circuit, identified by colors (e.g. according to the ATSB final report of the QF32 the green hydraulic line was disabled; according to the BEA final report of the AF4590 the Concorde had a yellow, a blue and a green circuit, ...). I understand the need to be equipped of several independant hydraulic system (redundancy) and the need of being able to identify those.

Thanks to the previous example, I figured out the hydraulic circuits are identify by colors.
Does it mean the hydraulic fluid is colored (useful in case of leak)? Does it means the elements of each circuit is painted accordingly (usefull for maintenance)?


texts: Why are piggyback launches done by dropping the carried aircraft and not by "fly-off" launches?

texts: Every air-launched aircraft I'm aware of, with the exception of the D-21 in combination with the M-21 carrier, has been launched by dropping it. Is there a reason why drop launches are preferred to "fly-off" launches from the top of the carrier?


texts: Different takeoff minimums between an Obstacle Departure Procedure (ODP) and a Standard Instrument Departure Procedure (SID)

texts:
It seems reasonable to me that an Obstacle Departure Procedure would include more "strict" rules (steeper climb gradient) than a SID, which is more "situational" and provides a specific direction in order to enter the en-route structure.
Take, for example, the takeoff minimums for the La Guardia Airport, page L16. It states, for Runway 13, "400-2¼ or std. w/min. climb of 280' per NM to 500".
On the other hand, this SID, also for Runway 13, clearly states as takeoff minimums "Standard with minimum climb of 563' per NM to 710, then ATC climb of 615' per NM to 2500, then ATC climb of 605' per NM to 4000, then ATC climb of 367' per NM to 5000". My question is, why does this SID require steeper climb gradient than the ones listed in Takeoff Minimums for La Guardia Airport?


texts: As you can see above, there are two small pipes next to the main engine exhausts on this Avro Vulcan(the one at Duxford). I'm curious what these pipes are/what they are for. Are they fuel dump pipes? If so why have two right next to each other?


texts:
What is the main reason why cruise flight in the transition layer is prohibited? For example if we have a separation of 1000 ft between transition altitude and transition level, why should we not maintain a level in this layer of 1000 ft?

I know about transition altitude and transition level but what is the cognitive reason of this rule?


texts: Where can I find that video of a college built blown wing aircraft?

texts:
I once found a video of a single engine, piston and propeller, high wing plane that had been built, or modified by a US college/university. They added a 200 HP turbine engine behind the baggage compartment up high in the fuselage and it drove a turbine compressor. Pretty much like a airliner starter turbine.

The high pressure air from the compressor went out to the flaps pivot axle and then into the flaps inner space. The flaps pivoted at the trailing edge, and so folded out by hinging down and back. Then, the edge that had been buried in the wing's underside forward of the pivot point was now the trailing edge. This trailing edge was a rounded tube of about 1.4 inches to 2.5 inches in OD. It had a jet flap blowing along the top surface and caused entrained air fom the top of the wing to go down 90 degrees.

It cruised around 150 to 200 mph, but landed around 30 MPH. Pretty incredible. I can't for the life of me find it again in Google or Youtube. Does anybody know about this project? I'd love to save that video down to my hard drive. Even better, I'd love to go see the plane.


texts: I was looking for the best glide speed of a DA42 with both engines out, but it seems it's not in the POH. In the emergency checklist, it only mentions a speed of 85 knots to maintain on final approach with landing flaps.


texts:
I was researching for the Eurofighter and I came up with a picture of its structure. I have three questions about its parts. I can't understand the role and the usage of them. Can anyone help me?

These 3 parts are the following:

Radar mounting bulkhead
Strobe light/anti-collision beacon
Engine bleed-air primary heat exchanger

*All of them are circled with a different color from me so to be focused and easy to find them. Also, their definition exists in the picture but I would like to also know, as I mentioned above, their role and their usage.

PICTURE

Thank you for your time in advance!


texts: What do pilots operating under FAA 14 CFR 91 have to do to fly in any of the Special Flight Rules Areas (SFRAs)?

texts: What do pilots operating under FAA 14 CFR 91 have to do to fly in any of the Special Flight Rules Areas (SFRA). Does each SFRA have its own requirements? I know there's a question already about the Washington DC SFRA. Is there a master list of these areas with corresponding requirements?


texts: Does Molecular Weight of a Gas affect its lifting properties at the same velocity over the same wing?

texts:
Let's say we test the coefficient of lift of the same wing at the same AOA and the same flow velocity at the same pressure.

The difference is wind tunnel A will contain helium (molecular weight 4) gas and wind tunnel B will contain air (average molecular weight around 29).

Which test will produce a higher lift coefficient?  Why?


texts: What is the largest and heaviest payload ever flown?

texts: Not counting the plane what is the largest or heaviest payload ever flown?


texts: What's the difference between Stress and Strain?

texts: There's a book for Engineers, entitled: 'Roark's Formulas for Stress and Strain', some describe it as 'High level Mathematics'. So what?


texts: How does Autoland work below decision height (200 ft)? Ie, what guides the plane until the radar altimeter notes the jet is at the right height to begin to flare? I've been searching the internet, and it looks like the plane simply holds its attitude for around 100 feet until the RA kicks in.


texts: Can I use PVC pipes for the rib on the wings of my homemade airplane?

texts: Can I use a PVC pipe as the rib of the wings of my homemade airplane?A rib is already load tested, and it failed at 40kg of weight and it is supposed to hold just 10kg in flight.


texts: Why is there no instrument taxi system for low-visibility operations?

texts:
In one of the comments on this answer regarding ILS category IIIc operations (or, rather, the lack thereof), it's mentioned that

There is no [radio] guidance for taxiing except the pilot's vision.

And, in an answer to another ILS IIIc question, it is stated:

There is no provision in the ILS system to provide for an auto-taxi or runway vacate. IIIc is just zero-zero and roll-out control, not auto-vacate as the linked AvWeb article seems to suggest. Its a logical extension of the FAA definition, however auto-taxi is not part of the CAT IIIc definition or system requirements. The only requirement is to get the aircraft on the runway and stopped.
...
Right now there is no airport approved for IIIc approaches because the aircraft would just sit on the runway, it has no way of taxiing in. Until an augmentation system like GPS with WAAS or LAAS, or the "Ground-Based Augmentation System" is developed further, automatic taxi is not there.
There is no provision in the existing ILS signals that allow for an aircraft to vacate the runway.

Given that the ability to land is meaningless without the ability to taxi off the runway and to the gate (this is why, even though today's airliners are perfectly capable of IIIc landings, there are, in practice, no such landings, as no airport is equipped to taxi an aircraft in from a IIIc landing), why isn't there an "Instrument Taxiing System" to allow zero-visibility taxi?


texts: Are there different sub-types of a mayday call and do pilots use them when declaring emergencies?

texts:
I was reading this pilot's quote from the Northwest Airlines Flight 85 incident:

  "This was a classic application of CRM. We were blessed and lucky that
  we had full flight crew augmentation. We had four pilots to work
  together in the cockpit. We had an excellent group of flight
  attendants on board; that became important later because we briefed
  this as a ‘red’ emergency, which means there’s at least a solid chance
  you’re going to have to evacuate. We weren’t sure we were going to be
  able to keep the airplane on the runway."

I'm aware of the Mayday call but does it have sub-categories?  He refers to a "red emergency". Do pilots always classify their emergency into sub-types when they declare it?

Any explanations on what the various sub-types are and how they are classified?


texts: Under what authority can the AIM overrule the FARs?

texts:
A commonly held belief among pilots is that the FARs are regulatory, while the AIM is not. Violation of a regulation in 14 CFR is punishable by the FAA, while the AIM contains mostly "good ideas" and violation of its precepts is only punishable to the extent that it rises to the level of FAR 91.13 (careless and reckless operation). The FARs must be published in the Federal Register and generally be subject to the rulemaking process, while the AIM can be updated by the FAA at any time, with no input from anyone outside the Administration.

With that background, consider a note in the AIM, at the end of section 5-4-5(l) about Fly Visual approach segments, on page 5-4-20 (page 346 of the current PDF version of the AIM):

  NOTE−
  The  FAA  Administrator  retains  the  authority  to  approve
  instrument approach procedures where the pilot may not
  necessarily have one of the visual references specified in
  14 CFR
  §
   91.175 and related rules. It is not a function of
  procedure
  design to ensure compliance with
  §
  91.175. The
  annotation  “Fly  Visual  to  Airport”  provides  relief  from
  §
  91.175 requirements that the pilot have distinctly visible
  and identifiable visual references prior to descent below
  MDA/DA.

This is, as far as I can tell, the only location where this exemption from FAR 91.175 is described. FAR 91.175 is quite specific in the elements needed before continuing beyond the DA/MDA, and does not stipulate that the Administrator has the authority to authorize exemptions. For an example of one that does, consider FAR 91.117(a):

  Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 m.p.h.).

What authority gives the AIM the ability to carve out an exception to the FARs? Are there other situations where the FARs are contradicted by a non-regulatory document without explicitly allowing exemptions or authorization by the Administrator?


texts: Why did the later versions of AeroVodocody L-39 Albatross find much market success?

texts:
The Aero L-39 Albatros had great success in the past.

Why didn't the later versions of AeroVodocody L-39 Albatross find much marketing success in the post-cold war modern aircraft market, like Aermacchi M-346, BAE Hawk, Korean T-50 golden eagle, Hongdu JL-8, and so on?


texts: Rules and restriction for toy UAV in India on very low heights ? (max 50 meter from ground )

texts: We want use RC UAV to take some pictures of  heritage forts (Gadh) around Pune. Do I need a special permission for that ? I have seen some one doing it before but just for to be sure I need to know. is there any official government website that can guide us ? I am so concerned because I want to do a research project.


texts:
This is something I have been questioning more and more often on how pilots do it. So, let's say we are flying on a new location and know very little about it. When flying around and keeping the location of the aerodrome we took off to later return back to it, how do we plan to consider which points to reference and which points represent what when flying?

Might be worth to mention VFR is in practice. Let us assume we do not have a GPS.

As an example where I have been flying I got references like a prison and a stadium that indicates a fly path back to the aerodrome, but I got to know those thanks to my instructor and become more aware of them. But when I think about it, at the start I had no idea. And when I consider way ahead once I have the ability to fly alone, I often think of how will I be able to understand which points references what, how can I quickly understand where I am and what is best for me to try and plan ahead to stay located when in flight.

Apologies if it is really obvious it is still something very recent to me and I have this worry recently. Just though it could be something I could start gain awareness, the sooner the better?

Thank you in advance!


texts: How do I get an FAA okay for a private runway?

texts: The county I'd like to put a private runway (for my use only) in doesn't require any special permits because the property is zoned Agricultural, BUT they do require some form of acknowledgement from the FAA that the FAA doesn't have a problem with it being in that location.  How do I go about getting something like that from the FAA?  Who do I contact?


texts:
On the SOFIA aircraft, the aircraft is designed to fly at very high altitudes (higher than what can be achieved by regular 747), with a cargo door open.

https://upload.wikimedia.org/wikipedia/commons/8/8a/SOFIA_ED10-0182-01_full.jpg

I know that oxygen mask are a standard feature for most airliners but:

How is the aircraft designed to handle this situation ?
What about redundancy ?
If there is supplemental oxygen, is it really without adverse effects ?

pic credits wikimedia


texts: Time to take the ATPL and license conversion

texts:
How long does it take to get the EASA ATPL license on average?
And if, after obtaining the ATPL licence in a particular country, you are recruited in a foreign country, do you need to re-take examinations in order to be able to convert it into a valid one in that country, or is the one obtained directly in your own country OK? For example, if you switch from an EASA license to a FAA. Thank you


texts:
Do airlines in the US or UK have to pay fuel taxes?

When looking at Jet-A prices on the Shell website, for example, it's unclear if the listed prices include taxes. Do they?


texts: How can I troubleshoot an intercom interference issue in a Piper PA-28?

texts:
Our Piper PA28-181 doesn't want to let us communicate via its own intercom panel in the dashboard. We connect via the pilot port and an "Intercom SL300". When connected there is a annoying sound on the phones, it seems to be the strobe or ignition (going to test it).

My questions:

Where would I get information regarding the intercom/audio wiring in old and small airplanes?
Is it possible to install a suppression capacitor?


texts: How to control torque effects on the ground?

texts:
I'm building a Lippisch ground effect vehicle with it's wingtips almost touching the ground, but because of torque effects the left wing actually does touch the ground, so it can't lift off. It even can't go straight.
Adding ailerons isn't an option because this problem has to be solved on te ground (zero speed) and not in the air (because it doesn't get there).
Does someone know something how I can solve this problem?


texts: Is there any disadvantage to slipping as a way to lose altitude?

texts:
I learned how to slip during my powered training as a way to lose altitude when too high and, of course, a way to track the runway center-line during a crosswind landing.

Quite a bit more emphasis was put on slipping during my glider training.  I guess the reason for this is pretty much common sense.  There is no concept of a "go-around" when landing a glider...you only get one shot.  That said, I don't practice slips often enough when soaring because purposefully losing altitude in a glider is counter-productive, except when too high in the pattern.

For this reason, I've now gotten into the habit of using a slip to descend when flying powered.  This allows me to practice slipping with the knowledge that I am guaranteed by virtue of having an engine to have the option of regaining that altitude.  Note: I usually only do this while flying solo since slipping can be a comfort issue for passengers.

This got me to wondering...

Questions:

Putting aside the comfort of passengers, Is there any disadvantage to always using a slip to descend when flying powered?
If not, why does it seem that this method of losing altitude is not used/taught more frequently?

Update after reviewing answers

I wanted to give this some time to stew before I checked an answer.  I came into this fairly (but not absolutely) certain that the short answer was no.  I think the responses confirm this.  I understand the need some have to "warn" against stalling, but I don't really see how this warning couldn't be applied to any maneuver and really has nothing to do with the fact that you are slipping,  short of making a mistake...like skidding instead.

The conclusion I'm taking from the answers is:

Slipping can be uncomfortable to passengers, pretty much for the same reason that healing in a sailboat can be perceived as uncomfortable.
Slipping is aerodynamically inefficient.  Since the objective is to lose altitude, this would appear to be a benefit, rather than a detractor.
That some planes, in some configurations, have restrictions on when slipping is allowed/recommended/optimal.
That slipping will get you down faster, thus making it preferred if getting down faster is the objective.


texts: What level of damage to an aircraft is acceptable to let it depart?

texts:
Yesterday (28 June 2016), a Bombardier Q400 from EPGD to EPWA made an emergency landing because of a blown tire, spotted by a passenger. Everything went smoothly and the plane landed successfully assisted by fire trucks.

You can see the article and video here (in Polish).

In addition to the damaged tire, I've spotted that there is some damage to some parts of the plane:

Is it okay to fly with that?
I guess it isn't important for the safety of the flight (it looks like some landing gear cover or something), but what damage to the airplane is considered safe for flight?
Is it possible to force the airline to repair non-critical parts?
I know that loose parts of airplanes could do harm when they fall off, e.g. during takeoff, and stay on the runway (like in the Air France Flight 4590 Concorde crash).


texts: How to calculate the amount of thrust of a autogyro during auto rotation?

texts:
When a autogyro/gyrocopter is in a horizontal steady flight the rotor should be able to provide enough thrust using the auto rotation principle if the horizontal speed can be regulated by the vertical propeller.

I was wondering how the amount of thrust provided by the main rotor of a autogyro during auto rotation can be calculated. All the characteristics of the autogyro and his blades are known.

The horizontal speed of the gyrocopter can be regulated by additional engines and they do not need a specification.


texts: Is it legal/possible to request a flight-path change from Domestic to International minutes after take-off, for a privately owned jet?

texts:
This is related to the recent escape of Carlos Ghosn from Japan. While we don't know the details yet, M. Ghosn allegedly boarded a private plane from a small airport near Osaka [and probably in a kind of "luggage"!].

In this event, it seems the private plane was aimed to travel internationally. But that brings the question anyway:

Would the pilot of a private plane be authorized to change their destination after take-off, and, more specifically, request to travel to a foreign destination, while initially, (before take-off) the plane was supposed to reach a domestic destination?

Probably not the case in this escape story, but since there is much less passengers verification on domestic flights, allowing the flight-path change (for a private plane) would make things much easier for someone (wealthy) who wants to evade a country.


texts: What is the reason for circulation of air around an airfoil? Based upon the circulation of air, why are airfoils shaped the way they are?

texts:
Foreword: I am an Aerospace Engineering student and next year is my third and final year, starting September 2019.

I was taught approximately 2 semesters ago that the correct theory of lift is that airflow circulates around the wing and so the upstream increases the velocity on the top surface while reducing the pressure, and reduces the velocity on the lower surface while increasing the pressure, which causes a difference in pressure that generates lift. Prior to that, I had the incorrect, yet simpler 'equal transit time' theory, which I'm guessing is taught at all universities at the early stage due to the simplicity of it. My problem is that I still base a lot of things on incorrect theories of the production of lift.

What causes air to circulate around a wing, or even a cylinder? My answer to that would be due to viscosity and boundary layer effects, is that right or wrong? I'm honestly unsure.
Since this theory was first being explored by analysing a cylinder, and it was determined that a cylinder can produce lift due to circulation of air (and the direction of upstream air), why do we have airfoils shaped in the way they are? I have many answers to this question which now I'm honestly unsure of due to the mix of theories in my head and some are based upon incorrect lift production concepts. Please give me a detailed answer for this question especially.


texts: What is the small openining on the bottom right of door 4R of an Airbus A321?

texts:
While observing taxiing A321 planes, I noticed that they had an open hatch-like opening on the bottom right of door 4R.  I marked it here on a picture I found online.

I could not locate it in the Airbus A321 Aircraft Characteristics manual.  What is it for?  Why was it open?  Does it stay open during flight?


texts: What does the statement painted on this P-51 mean?

texts:
In this video, there is a shot of the side of a P-51 Mustang.

The side of the plane is painted with:

  SERVICE THIS AIRPLANE WITH GRADE 100/150 FUEL. IF NOT AVAILABLE T.O. 06-5-1 WILL BE CONSULTED FOR EMERGENCY ACTION
  SUITABLE FOR AROMATIC FUEL

What does this mean?


texts: How much responsibility does ATC have to alert a flight about being in a dangerous situation?

texts:
There have been quite a number of accident reports referenced here at Aviation.SE about commercial (passenger or freight) flights executing controlled flight into terrain on approach for landing. The accident reports always seem to revolve around the pilots not knowing they are too low, failing to recognize or respond to the GPWS, etc.

While I understand that the pilot in command has the final say on what happens on board the aircraft, ATC is responsible for giving the PIC instructions to get him safely to the end of the runway.

In the case where ATC has given the PIC the approach route, whether VFR (flight following) or IFR, how much time, ability, and requirement does ATC then have to monitor that flight to ensure that it's on the expected course and at expected altitudes? In other words, how much responsibility does ATC have for failure to monitor the situation and allow these accidents to happen?

If necessary, differentiate between different CAAs, but I would think the answer would be fairly similar around the world.

There are a couple of nice answers, but they're not addressing (in my head, at least) the question I was attempting to ask, so it seems I didn't ask it well. I'll clarify further:

In a situation such as Eastern 401, the pilots had already contacted the tower to indicate that they had an issue - the nose gear lock light failed to illuminate. While attempting to determine what the cause of the problem was (bulb burnt out or gear not actually locked), they forgot to aviate and flew into the ground. In a situation like this, particularly where ATC has been notified that there was an issue with the flight, it seems to me that they (ATC) would have been more alert to the flight and notified the pilots that they were descending when they should have been holding a steady altitude.

This is the type of situation that I'm asking about (though not specifically EA401), and I'm wondering what role, if any, ATC should or does take in monitoring and alerting flight crews to altitude deviations, especially on approach.


texts: What is the purpose of the fin sweep on small piston airplanes?

texts: Why some small piston airplanes, like Cessna 152/172, Tecnam P2008 and many more, have the vertical stabilizer with a sweepback? I don't think that those airplanes may encounter compressibility effects, so what is the reason?


texts: Why aren't there brake lights on aircraft?

texts:
Why don't aircraft have brake lights so you can see when an aircraft in front is slowing down?

I know there are air traffic controllers to control aircraft but they cannot do much about an aircraft's speed on the ground, it is down to the pilot.


texts: How can I tell from the location of flow separation if an airfoil is stalled?

texts:
I am in the process of completing a carbon airfoil for my track car (sedan) and I am looking to determine stall angle visually.  AKA, wool tufts and highway runs with my GoPro pointed upward from the trunklid.

Since I don't really know the angle of incidence at which the air coming off the rear window will hit the wing, visually looking for flow separation is really the only way for me to determine my max angle and work down from there based on the car's balance at the track.

Is there a paper (or common knowledge) regarding over what % of chord length flow separation must occur for the wing to be considered stalled?  Highly cambered airfoil, Selig S1223, 11.5" chord, 66" span.  I have searched for papers on the topic but cannot find anything.

Thanks!


texts: If the APU is switched off but the APU bleed is on, will the engine bleed valve close automatically?

texts:
On he A320 family aircraft, if the APU is switched off but the APU bleed is on, will the engine bleed valve closed by the Bleed Monitoring Computer (BMC)?
This what I understood after going through the APU chapter of the FCOM. Just wanted to confirm because the way I understand it is that the APU bleed valves will not open since it requires a minimum of 8 PSI, so the engine bleed valve should be open.


texts: Does the AC-130 have de-ice or anti-ice protection for wings and surfaces? Can it fly in icing conditions? Looking at many pictures I see no sign of a shiny "hot wing" leading edge nor any boots. Does anyone have more information on this?


texts: What's an estimate for the cost of the cockpit technology on a 747 or 777?

texts:
Can anyone share what the percentage cost or dollar costs of cockpit instruments and related software is within a 747 or 777?

PS-  I'm a physician working in medical safety.  Physicians can no longer memorize it all (haven't been able to for decades- but now admitting it with more frequency).  They need instruments as in a medical cockpit.  Currently hospitals spend hundreds of millions on electronic medical records, but do not heavily invest in software to aide diagnostic and therapeutic decisions.  I am trying to develop a comparison between professions that deal with complex systems and the type of investments in software and guidance systems to handle complexity.  Thanks for any help!


texts: What is the historical reasons to start Belgians registrations with "OO-"?

texts:
For many countries, the registration number begins with a obvious letter (F for France, D for German (Deutschland I guess), C for Canada,...). For other, historical reasons have already been covered here (e.g. Where did the US 'N' registration letter come from?).

But for Belgium, I find it weird to begin with OO. Is there an historical reason for that? if so, what is it?


texts: Is there a formula to calculate take off runway distance for commercial planes?

texts: I want to be able to calculate the take off runway distance that a plane needs depending on factors such as weight and plane size, etc. I know that graphs exist in the pilot handbook to do this but is there a specific formula that I could perhaps put into a program?


texts: Are the fastest moving pieces of a jet engine supersonic?

texts:
A jet engine is composed of fast moving pieces. Those pieces are moving into an airmass different form the ambient airmass the aircraft is flying into.

The turbine pieces are spinning quite fast, thus its blade tips may be moving at a supersonic speed. But, the airmass may also be spinning modifying the speed of the blades into the airmass. Moreover, the temperature of the air at this stage may modify the speed of sound.

The first stage of compressor is spinning at a much familiar air temperature and pressure, thus it may be easier to find if those compressor's blades' tips are moving faster than the speed of sound. But pressure (and thus temperature) is not the same before and after each compressor stage. It may be hard to define the speed of sound for this airmass going through the compressor.

Given the airmass inside a jet-engine is different from the ambient airmass, are there any moving piece inside a jet-engine whose velocity (frame of reference: the airmass in which it is moving) is greater than the speed of sound?


texts: Is a new type of TSA pre-approval required before commencing flight training?

texts:
A friend of mine owns a flight school in the states.  A Designated Pilot Examiner (DPE) has informed his staff that a new TSA regulation will require all new prospective flight students to meet with a DPE prior to starting any flight training.  That is, every new student will need permission from a government agent prior taking a flight lesson from any flight school (61 or 141).

I would typically dismiss this as nonsense but, considering he source of the info is a DPE, I'm curious to know if there is any truth behind this rumor.

Does the TSA plan to implement rules that require every prospective student to seek pre-approval from a government agent (not just a flight school) prior to beginning flight training?

Current regulations require the flight school, or independent CFI as the case may be, to verify citizenship and retain records.  This can be done in minutes.  The DPE indicates that appointments are required and additional fees assessed for the new layer of government approval.

Say it ain't so!


texts: In the ARINC specification, does "sig bits" include the sign bit?

texts: In the ARINC specification, there are sections where all of the different labels (and their pay-loads) are described. In each of the tables where the labels are defined, there is a column called sig bits. For where the labels are designated as BNR, do the sig bits include the sign bit?


texts: What is this aircraft, and what country makes it?

texts:
What is this aircraft and what country produces it?

Source: Google Images


texts: Why are 4 engine civilian turboprops not produced anymore

texts:
As per subject why are 4 engine turboprops not produced anymore for civilian flights if turboprops are so efficient?

How comes the military still use them (see Airbus A400 and C130)

It would be amazing to fly on a 150 seater powered by 4 propellers.

What favours jet engines?


texts: Do flight recorders need more efficient antennas?

texts: At a frequency of 37.5 kHz, a quarter wavelength is about 2 km (1.24 miles) long. How does the black box efficiently radiate anything if it is not attached to 2 km of antenna?


texts: Is inverted flight possible under these conditions?

texts:
My understanding of flight is that the primary aspect is the angle of deflection, and the purposes of the shape of the wing is to maximise efficiency. Could a commercial airliner with asymmetric aerofoil sustain inverted flight by keeping its nose up, or something similar?

For the purposes of the question, ignore issues with the fuel or engine, and assume that the wing shape is fixed and not specifically built to accommodate inverted flight, including not having flaps or anything in the aileron department.


texts:
I wanted to know the name of equipment that controls the control surfaces of an aircraft by taking commands from the pilot through it's hotas stick. The aircraft could be a combat 50's or 60's a/c, so possibly there would be a specific name of such control equipment.
Will this equipment be the most safety critical equipment in such an aircraft compared to other equipment such as NAU (Navigation and Attack unit) or will there be any other more safety critical equipment in an a/c?
Edit: Let the a/c be a Mirage.


texts: What are the components of a crew pairing?

texts:
I need to do some modeling for an FRMS (Fatigue Risk Management System). By crew pairing I mean a sequence of flights that starts and ends at crew base. From my understanding, crew pairings are made of:

Duty periods, which include flight duty periods (where the crew actually flies).
Between duty periods, rest periods (overnight rest for example), or
You can also have deadheading before starting another duty period.
So basically when the crew finishes one duty period, he/she either has a rest period or some deadheading before starting another duty period.
Is there anything else that should be included in the pairing?


texts: On the A320 why do we follow this particular sequence of taking flaps and gear?

texts: First we take flaps 1 then 2 after that we lower the gear followed by flaps 3 and full. My thinking is that this will avoid any GPWS warning is that it or there is something else also to it.?


texts: What does it mean when an airplane has the "super" call sign?

texts: What does it mean if an airplane uses the "super" designation after their call sign on the radio?


texts: What is the best altitude to penetrate a thunderstorm?

texts:
135.293(a)(7)(iii) requires that pilots be tested on:

  (iii) Operating in or near thunderstorms (including best penetrating
  altitudes), turbulent air (including clear air turbulence), icing,
  hail, and other potentially hazardous meteorological conditions;

So what are the best penetrating altitudes when forced to operate in a thunderstorm?

The most obvious answer is to stay out of it in the first place, but the reg requires us to come up with an answer....


texts: When calculating takeoff performance why include airport elevation in pressure altitude?

texts:
When calculating the pressure altitude for aircraft performance I learned to calculate it the following way:

Pressure Altitude = (29.92" - altimeter setting) * 1000' + elevation

So at an airport at 3000' elevation and an altimeter setting of 29.92" I can expect the aircraft performance to be that for 3000'.
I never questioned that but now I wonder why don't we just care about the altimeter setting? If the altimeter says the station pressure is 29.92" sea level, but I am at 3000', then the airplane still thinks it's at sea level when it comes to performance. Is that wrong?

Same for an airport at 3000' elevation and an altimeter setting of 28.42" I can expect the aircraft performance to be that for 4500'. Again, why not 1500'? The airplane should think that it is, regarding pressure, 1500' above sea level.

I think that would make sense for en-route performance. If the station pressure along the way is 29.92" and I fly above at 4000', my pressure altitude will be 4000' (0*1000 + 4000). If my station pressure however is lower, say 28.92" for instance, then the pressure altitude above at 4000' would be 5000' ([29.92"-28.92"]*1000 + 4000).


texts: What is the difference between Review and Analysis in DO-178C?

texts:
In the context of DO-178C, what is the difference between review and analysis of the outputs of the software development processes?

Are they both the same?


texts: What is the origin of the waypoint CLAWW and PAHTI(New England region)?

texts:
I'm the reading the book "Sayfaring".
There are two waypoints I don't get the origins in the sentences.

1) CLAWW

"Boston has lifted a particularly intricate constellation of itself
into the ether above New England. There is PLGRM, for the
region’s history; CHWDH, LBSTA and CLAWW for its food"

2) PAHTI

"Even the region’s speech –WIKID, followed by PAHTI – seems to be mapped


texts:
This is sort of the reverse of an aircraft-identifcation question.

I am attempting to build a virtual model of a Gee Bee R1 (for fun). Unfortunately I haven't had much luck finding plans or images of the inside of an R1 cockpit. The best I could find is this image of a miniature model of a R2 instrument panel:

And this still from a video about a modern-day flying replica (also an R2):

Having desperately reached as far as the second page of google images without success, I've given up trying to find anything better. But if anyone knows some better sources, please let me know!

With very limited actual knowledge about any sort of aircraft, I have no idea which doohickeys do what. So my actual question is, can anyone identify what each of these things likely indicates or does?


texts: Could a plane take-off at 20,000 feet above sea level if the temperature is above freezing?

texts: I’ve read that “humans have survived for two years at 5,950 m (19,520 ft, 475 millibars of atmospheric pressure), which is the highest recorded permanently tolerable altitude” and that “Daulat Beg Oldie...has an airstrip at an altitude of 5065 meters (16,614 feet), which is the world's highest airstrip.”  I can’t seem to find any record of the highest horizontal take-off in history.  I really want to know if there is an altitude at which humans can survive but take-off is impossible.  Or if there are any other conditions at which humans could survive naturally but where take-off or flight is impossible for some reason other than temperature, weather or terrain.


texts: Why would short-haul flights be pressurised at a higher cabin pressure?

texts:
In the article here : https://abcnews.go.com/Health/Healthday/story?id=4507808&page=1 it is claimed that

  Short-haul flights are usually pressurized at 5,000 to 6,000 feet while long-haul flights are closer to 8,000 feet, according to Thibeault, [M.D., medical advisor, IATA].

But why would this be? My understanding is that the cabin pressure is chosen as a balance of:

what the aircraft can withstand without slow structural deformations, so that it is functional for many years
what is most comfortable for the passengers
most fuel efficient- pumping in air requires some fuel.

With regards to comfort, I should think that low pressures take their toll after a few hours (I think I read 3-9 hours, for people developing altitude sickness symptoms at about 8500ft equivalent cabin pressure).

The only guesses I have at why short-haul flights can operate at higher cabin pressure is:

the aircraft body won't have as much structural change with a short-term pressure difference
the plane can 'retain in' air pressure without actively pumping it for some time on the order of hours/ half-hours, so it is not so energetically costly.


texts: How feasible digital radio communications would be?

texts:
Its been over 100 years since we first flew and we still use analog radio with parasites and "radio effect" which changes your sound.

Why don't we ditch the old system and make a mandate a new law where any aircraft that wishes to fly in a controlled airspace has to be equipped with two digital radio communication systems?

What would the coverage costs be like? Doesn't digital systems require less power and antenna size etc to work which would make it better?


texts: Can I fly solo when practicing IFR under the hood?

texts: If I have my instrument rating can I log simulated instrument time under the hood while flying alone as the PIC? Or does a safety pilot have to be present?


texts: What is the total pressure of an air stream in motion?

texts:
This question is from a French aeronautics exam so I translated as best I can but I suck at these terms in English. Anyways, can someone please explain this question to me because I'm just really confused by other explanations.

In an air stream in motion, the total pressure is equal to:

- difference between dynamic pressure and static pressure.
- sum of dynamic and static pressures.
- difference between atmospheric pressure and dynamic pressure.
- sum of static and atmospheric pressures.


texts: If jets carried pure O2 to use for combustion, would they be more efficient?

texts: Air is around 21% Oxygen. The bulk of air is non-flammable Nitrogen. Wouldn't surrounding the jet fuel with only O2 create more efficient and clean combustion?


texts: Do any civilian aircraft use AESA or PESA for weather radar?

texts: Are there any weather radars in civilian aircraft that uses active or passive array techniques? I know that the most of the radar used in the civilian aircraft use doppler effect and latest military aircraft use AESA radars.


texts: Are there any methods to predict the location of a jet aircraft from its sound?

texts:
At times there are military fighter aircraft flying overhead of my location (MiG-21Bis and Su-30MKI).

The first indication of their presence being the sound, that obviously causes one to look up to try and acquire them visually. The sound can be distinctly made out to be changing, as if for a moving object (not sure pure Doppler shift and/or change of source location).

However, almost all the times the aircraft are actually sighted in a totally different location from where the sound 'seems' to indicate them to be (and sometimes not sighted at all)! This seems obvious due to the relatively slow speed of sound and the fast speed of the aircraft.

However, are there are any suggested method(s) to locate such aircraft visually based on the sound?


texts: Why do TACANs not have a symbol for compulsory reporting on IFR Enroute Low Altitude charts?

texts:
I am studying the IFR Enroute Low Altitude legend, and I noticed that all NAV Aids other than TACAN have a compulsory reporting point icon.

They do appear on the STAR/DP legend.

Why do TACANs not have a compulsory reporting point icon on the STAR/DP, but not IFR Enroute Low Altitude?


texts: Why aren't the undersides of military aircraft painted bluey-grey to camouflage them against the sky?

texts:
Why aren't military aircraft painted a bluey-grey colour to camouflage them against a bluey-grey sky?

(I researched this but couldn't find a clear answer)


texts: How does pilot know when to trim when flying an aircraft that have fly by wire flight control computer

texts:
My understanding of trim (on non fly by wire aircrafts) is that when the pilot feels force on his column or side stick, he trims the aircraft (either up/down) until the forces on the stick or yoke are neutralized. But in fly by wire systems, the pilot does not feel any force on the stick or yoke. In such case how does pilot know when to trim the aircraft (be it pitch/roll/rudder trim).
Or does flight control computer computes the trim required automatically? In such case, what happens during the direct mode (or alternate law) when flight control computers are no longer in control and pilot commands directly go to actuator controller electronics.


texts: Do the polar curves have large differences in takeoff than in landing?

texts: I was wondering if the polar curve has differences in the takeoff due to the smaller extension of the flaps (this is half that in the landing) that changes the AOA for $ C_ {la} = 0 $. In addition, should I calculate the landing polar on approach?


texts: Why did the pilot flying pull back in the moments after the auto-pilot disconnected on AF447?

texts:
In the AF447 disaster, one of the elements that contributed to the crash was an "excessive" nose-up input shortly after the disconnection of the auto-pilot.

This caused the aeroplane to climb and lose airspeed, precipitating the ultimately fatal stall.

Why did the pilot flying pull back (excessively) on his stick? Did the investigation find probable causes?

He was at the same time correcting for turbulence-induced roll. Would a nose-up input in such circumstances be appropriate?

If so, how easy is it for a pilot to make an excessive input of that kind without realizing it, and what would normally prevent that from happening?
If not, is there any explanation for why he might have made it?

Most of the crew's actions in the incident are comprehensible, even if they were incorrect responses. They make sense in the context of the situation, and it's possible to have a fairly clear picture why they made the judgements and decisions they did.

Is there a good explanation for that initial nose-up input, that makes sense of it too in the context?


texts: Why separate autopilot controls for course and heading?

texts:
Is there an explanation better yet equally pithy than the beneath, in fewer than 50 words?

Course is the direction in which the aircraft is flying over the ground. Heading is the direction in which the aircraft is pointing.

This quote motivated me to question the quote beneath:

[2.] See it like this... When Tomtom directs you from Amsterdam to Barcelona via Paris, Barcelona is your final 'course', but for now... you're 'heading' towards Paris... (taking in mind that you just left from Amsterdam...)
[3.] Other example: If you're doing an approach for landing at, let's say, LEBB (Bilbao) Airport on RWY 30, your Course is 300 but you can have various 'headings' TOWARDS your final course, Course 300 for RWY 30.

Why would heading and course need be controlled separately? If I'm flying to Paris first, then wouldn't I just input the heading to fly to Paris? Only after reaching Paris would I change the heading for Barcelona. Isn't 'course' redundant?

In the 'other example' above, isn't 'heading' redundant? Wouldn't I just input the course for Rwy 30 which is by definition 300?

Does anything above explain this picture, where the crosswind requires the plane to angle its nose to land?


texts: What is it called when you roll without yawing or pitching?

texts: My instructor made me do an exercise that consists of banking the sailplane left and right around 30 degrees without moving from the axis. I need to aim for a specific point, and start with the exercise. This is a coordination exercise but does it have a name? It's like a dutch roll but I need to stay in the roll axis without moving.


texts: What is the exact meaning of CAVOK and CAVU? How are they used by pilots and ATC?

texts:
Do CAVOK (ceiling and visibility okay) and CAVU (ceiling and visibility unlimited) have formal definitions worldwide?

CAVOK, source: formercaptain.ca

Are they used in ATC communications?


texts: What are the requirements for a foreigner to become an Air Traffic Controller in Sweden?

texts:
Background
I am an Air Traffic Controller (ATCo) working in Greece and I'm looking for information about working in Sweden as a foreign ATCO. I speak Swedish and my wife is of Swedish origin (not a citizen though).
My question is...
Is it possible for foreigners who know the Swedish language to get a job in ATC in Sweden? Where can I find vacancies for ATCO positions in Sweden?


texts: What are the effects of adding winglets to an aircraft not designed with winglets originally?

texts: Are there any positive advantages or catastrophic effects on adding winglets to an aircraft not designed with winglets originally?


texts: What is the procedure when a required A/D inspection via an AMOC has gone overdue?

texts: I recently purchased an aircraft that was legally (and otherwise) airworthy.  There is a visual inspection due (any private pilot can perform it) every 10 hours, but the ferry pilot may have overlooked this during the 18 hour ferry trip.  The inspection due time has now gone over the 10 hour requirement.  Are there additional requirements other than just inspecting again for compliance, or must something be submitted to the FAA as to report a non-compliance issue?


texts: What is the risk of icing with water / moisture on wings prior to takeoff?

texts:
If a plane without any deicing equipment has water moisture on the wings (say, from sitting overnight) and that plane is then flown to an altitude which will have temperatures below freezing, what is the risk of that initial moisture causing icing concerns?

For the sake of hard examples:

Plane: Piper Cherokee 140
Air temperature on ground: 40°F (4°C)
Air temperature at cruise altitude (3500ft): 28°F (-2°C)
No visible moisture in the air, the only moisture is the moisture on the wings prior to takeoff.

Questions:

Will this be a problem?
If it is a problem, what is the best course of action to protect against the icing concern?


texts: Advantages of square over circular engine nozzle?

texts:
The F-22 has square nozzles, while the Russian Sukhoi PAK FA has circular nozzles.

There are both 5th generation planes, but with different nozzles, why?


texts: Why airliners fly so high even when winds are more suitable at a lower altitude?

texts:
While playing a flight sim, I noticed West winds were very strong at levels >FL350 and weaker around FL270 above the US.
I took a look at Flight Radar 24 to see at which level actual airliners were flying, and I was surprised to see they're mostly over FL350, despite the lower ground speed and increased fuel burn I assume should occur

Is there any reason for that ?

FL270 :

FL390 :


texts: Could a plane land vertically in a strong headwind?

texts: I know there are VTOL craft meant to take off and land with a vertical trajectory. But, under the perfect wind conditions, could a normal airplane ever land (safely) with a vertical or nearly vertical trajectory?


texts: How to call a cartesian (END) coordinate system, that is referenced in surrounding air?

texts:
I'm looking for the correct/usual terminology for a coordinate system, that is moving with the wind.

I do calculations in a Cartesian East-North-Down (END) system. When taking wind into account I'd like to move this system with the wind and transform it back to an earth-fixed END-system afterwards. So basically, the reference point of my coordinate system isn't a point fixed on earth, but an air molecule that is blown with the wind.

Is there a common name for such a coordinate system?

Firstly, I thought of it as the "Wind-Frame", but after some investigations I conclude, that the term "Wind-Frame" is meaning a different system which is also rotated and not only moved in the plane.

So if any body knows, I'd like to hear from you.

I use this because I calculate Dubins paths and want to take wind into account. So when projecting the path of the plane on earth, you will see a trochoid, but the plane itself will fly a plain circle in its surrounding air. This eases calculations a great deal.


texts: ETOPS 330 vs ETOPS 370 etc; how are the exact minute ratings derived?

texts:
I am curious how the ETOPS minutes categories are arrived at. i.e. Say, ETOPS 330 vs 370.

What extra abilities would the 370 type have demonstrated that the 330 didn't have? Was it just that the test flight on single engine was longer? Or something else in the design limits the type to a 330 minute rating while on the drawing board? Is it the MTBF of a component? Or is the 330 minute time back calculated based on actual empirical testing and the associated failures?

On ground and maintainance procedures is there any substantial difference when dealing with a ETOPS 330 aircraft vs and ETOPS 370 aircraft?

Could there be (say) an ETOPS 430 in the future?


texts: What altitude to use for IFR off-airways route

texts:
Say I want to fly off-airways (both Victor airways and T routes) for my IFR flight, direct to my destination in the US.  How do I know what my off-route altitude should be so I can file for that?
I would expect this would be an altitude above the OROCA and suitable for direction of flight, however I encountered this in the Instrument Procedures Handbook:

OROCAs are intended primarily as a pilot tool for emergencies and
SA. OROCAs depicted on en route charts do not provide the pilot
with an acceptable altitude for terrain and obstruction clearance
for the purposes of off-route, random RNAV direct flights in either
controlled or uncontrolled airspace. OROCAs are not subject to the same
scrutiny as MEAs, minimum vectoring altitude (MVAs), MOCAs, and other
minimum IFR altitudes. Since they do not undergo the same obstruction
evaluation, airport airspace analysis procedures, or flight inspection, they
cannot provide the same level of confidence as the other minimum
IFR altitudes.

This suggests we cannot trust the OROCA.  Then I suppose the 14 CFR 91.177 indicates I need to be at least 2000 ft above the highest obstacle within 4nm of my course in mountainous areas, or 1000 in non-mountainous areas.  But how do I know what this is without using OROCAs?  Do we check sectional charts, or is there something more practical?  Checking a sectional seems reasonable on the ground for filing, but not so if diverting in the air and flying direct to some other airport on an off-airway course not planed on the ground.
Thanks for any help!


texts: Does wing sweep affect the direction of lift?

texts:
Given both a straight and swept wing (identical otherwise), exposed to the same airflow, would the direction of lift be the same? Please see below a crudely drawn example of my thinking.

Additionally, as angle of attack is defined as the angle between the airfoil's chord line and the direction of oncoming flow, is there a name given for the angle between the span line and direction of oncoming flow?


texts: When to start descent entering a racetrack under NORDO?

texts:
Scenario:
I am flying in IMC, and communications fail completely. IMC persists up until destination, where I will be conducting the following instrument approach:

I am flying direct to ZUNAD from the north, approaching it on a track of 200°. When within the prescribed MSA, I descend and maintain 4,300 ft. At the moment I reach ZUNAD, I will be performing a teardrop entry into the racetrack/procedure turn (heading of 211° after ZUNAD for one minute, then right turn direct to ZUNAD).

Question:
Can I start descending to 2,600 ft just after passing ZUNAD, entering the procedure turn on that heading of 211°, or should I wait until I cross ZUNAD again and become established on the racetrack pattern?


texts: How does a Fenestron remove or reduce the tip vortex losses in a helicopter?

texts: How are Fenestrons (or fantails) able to reduce the tip vortex losses in a helicopter?


texts: How does wing shape impact shock structure?

texts:
I am trying to understand what the 3D shock structure would be for a wing in supersonic flow. Suppose we have a wing which is made of double-wedge airfoil cross-sections.
If we view the shock structure over the airfoil (side view), it would look like so:

Now, if we look at the top view, we would see the following structure (top view):

Questions:

Is the shock seen in the side view (airfoil shock structure) related to the one seen in the top view?
How would the shock structure change if the airfoil is kept the same but the wing is swept more?
(If you can show some 3D plots for the shock structure, it would really be helpful!)
Can you explain what determines the shock angles in this picture (is it sweep or airfoil shape or both - and which is more dominant)?


texts: where can I find the codes used on Skyvector charts?

texts:
on https://skyvector.com/?ll=51.25181634927654,3.6845398064171233&chart=301&zoom=1 at N51°14.00' E3°46.96' is see a code "EBW" (blue circle with in-pointing teeth). I searched everywhere but couldn't find what "EBW" stands for. On Google maps I only see agricultural land there.
I also see similar codes like EHM and EBM, and would like to find an index for such codes.


texts: How can you tell what position the flaps are in whilst on a commercial aircraft?

texts: I am flying with thomson soon and want to be able to tell what position the flaps are in. How can i figure this out?


texts:
Let suppose an emergency aircraft has made an overweight landing. The brakes are white hot, and the fire crews are requested to be on scene.

What can be done about the hot brakes? Can they just shoot water at the gear assembly? If flames are visible, would they shoot foam instead?

This related question asks how do fire crew inspect the brakes, but not what they do when the brakes are known to be very hot.


texts: When should cross country flights occur in flight training

texts:
Question about 141 flight schools.  I'm 52 hours into flight training and my 141 flight school wants me to do my cross country work prior to a maneuvering stage check, landing stage check and solo endorsement.

Is this a red flag, meaning the school is milking me for my money?

My understanding is there are two 50 NM flights and 150 NM flight that occurs with instructor and then need to be completed individually.

Monetarily  I want to know that I'm endorsed to fly solo before spending the money on the dual cross country.

My school is unwilling to endorse Solo flight until I have fulfilled cross wind landings with winds at 15 knots.

Thank you


texts: Why are some contrails longer than others?

texts: I've often noticed that planes flying on more or less the same track, headed in the same direction leaves different contrails. By different I mean how long they stay visible and the length of them. Why is this so? Is it weather related?


texts: Are ATC assigned altitudes temperature compensated?

texts:
For the purposes of commercial air traffic operating in a terminal/approach space area that has temperature compensation applied to waypoints in the active flight plan, if ATC assigns an altitude, will the assigned altitude be a temperature compensated altitude?

If so, how does ATC know what factor to apply to the procedural altitude?

If not, then an ATC assigned altitude (non-compensated) could be interspersed with compensated altitudes and possibly cause non-monotonic descent or ascent.


texts: Can this design provide more lift force than thrust from engine?

texts:
The problem is depicted in the picture:

Generally, why we don't use engine blow wings to fly? Can we use wind-tunnel-like wing to generate lift force?

Can it generate more lift than thrust? If it can, how many times?


texts: What is required for an EASA pilot to fly an airplane with retractable gear, flaps and variable pitch prop?

texts:
Here is the FAA's complex airplane definition:

A retractable gear (not necessary for a seaplane).
In-flight adjustable flaps; and.
A controllable pitch propeller.

How is this airplane defined under EASA and what is required to fly it? A pilot with EASA PPL is able to act as a PIC with retractable gear and flaps; or flaps and controllable pitch. Can he fly an airplane that has all three elements without any additional ratings or endorsements? Or are there any other requirements to fly this type of airplanes?


texts: So, the great old argument, flyer-by-wire systems vs conventional hydraulics. I was wondering which one was better and why. Which one is safer? Pros and cons in terms of safety? Basically, I just wanted to know roughly the pros and cons of both systems.


texts: Can I request VFR flight following in a practice area and without a flight plan?

texts: Can you request VFR flight following for your local non towered practice area?  Can you have flight following without filing a flight plan? Can you also receive FF when flying low (800 AGL) locally for separation from pipeline patrols and ag spray planes?


texts: How should airline pilots find out about military activity along their route?

texts: What sources of information should a commercial pilot review before takeoff to become aware of military activity that might pose a risk to their flight?


texts: What do you squawk when multiple conditions apply?

texts: There are three standard transponder codes for exceptional situations: 7500 (hijacking), 7600 (radio failure), and 7700 (general emergency).  Which code do you use if multiple situations apply?  For example, if a hijacker smashes your co-pilot's head into the radio, do you squawk 7500 for the hijacker, 7600 for the smashed radio, or 7700 for your co-pilot's head injury?


texts: Does a Boeing 737 NG have Air Data Modules for the standby Pitot probe and static pressure port?

texts: In other words, how does the ISFD calculate the air data and IR parameters? Or is the ISFD an ADM by itself?


texts: Why would a Su-25, which has more power and is much lighter than an A-10, only fly half as high?

texts:
On the web, on several sites, the A-10 is listed with a ceiling of 14 km, the Su-25 with 7 km, although there is data that puts the height for the Su-25 at 10 km.

Nevertheless, why would the Su-25 fly only half as high as the A-10 knowing that the Su-25 has more engine power and is much lighter?


texts: Steady-state simulation of pitching motion

texts: Is it possible to perform a simulation of 'steady-state' pitching motion of an aircraft/wing? Is there any method where we can analyse the effects through a steady-state simulation of a pitching motion? I have seen numerous papers/articles where the unsteady simulation has been carried out but none related to steady-state.


texts: What if one of the navigation lights failed to function on a certified aircraft?

texts: What is the implication if one of the navigation lights failed to function, would it affect the airworthiness certificate of the aircraft?


texts: Airframe parachute on commercial airlines

texts:
My question, would a multi-deployment airframe parachute system be viable on a commercial airline? For example, Grumman & Cirrus already use this system.

As with the automobile industries, they were found to be culpable of many road deaths prior to implementation of seatbelts (refused by all the automakers at the time), so is it the airlines' responsibility for not making flight safe enough when the technology is there to implement?

You cannot buy a new car without it having airbags, why not airframe parachute on every new plane as a standard?


texts:
While studying the PBN (FAA Order 8260.58A) and TERPS (FAA order 8260.3D) documents, I still have some trouble figuring part of the logic behind the naming and definitions of the published IAP Charts. Specifically, I still have not figured out which Lateral Navigation System is combined with which Landing System (if this is how it's done in practice). Take the following examples:

Technically, ILS is a landing system, to the best of my understanding, at least. I expect that it can be combined with any Lateral Navigation System used in-flight, as long as the necessary equipment is available. Therefore, I would expect to find charts using RNAV with ILS. This would mean, to me, that, "RNAV-equipped" flights can still use an ILS Landing System. Is this combination possible?
According to Chapter 3 of the PBN manual, the RNAV(GPS) procedures can also be combined with a GLS Landing System. However, I have not found any published IAP chart mentioning the GLS minima. To my understanding the RNAV(GPS) procedures with GLS Landing System are published separately under the name "GLS". Is this correct?

My confusion can be described, in short, as follows: because I have seen RNAV (GPS) procedures being combined with LPV or LNAV/VNAV, which are Landing Systems, and ILS is also a landing system, I thought that the general idea is that Lateral Navigation Systems are combined with Landing Systems when designing IAP procedures. Is this correct? If yes, where can I find the possible combinations. If no, then what is the logic behind this, what am I missing?


texts:
I was watching this video of a FedEx MD-10 landing and some questions came up, of course again the unprofessional YouTube comments didn't help.

How many miles before the runway should an airliner put the gear down?
Was the aircraft in the video too close?
At which distance does radio altimeter warn the pilots?
Is the following YouTube comment accurate?

  This was FedEx flight 1356 and I can tell you what happened. During approach there was an anomaly on the left slat and it was being watched. Also during approach engine no.1 was heating up to unacceptable levels and because of all of this the gear wasn't lowered right away. It was only due to TCAS and the alarms on board that it was noticed as the aircraft was approaching it's minimums. Upon landing the crew was reprimanded for not following proper procedure and was suspended with pay.


texts: How are the takeoff V speeds calculated?

texts:
What is the actual formula for calculating the takeoff V speeds of an aircraft with any configuration? Specifically, I mean V1, Vr and V2

I know there are many factors, but what are they specifically and what operations are used on them in an overall formula?


texts: Does the FAA construe FAR 91.225 to prohibit aircraft w/o electrical systems w/o ADS-B-out from flying above 10,000' MSL unless below 2500' AGL?

texts:
Does the FAA construe FAR 91.225 as imposing a general prohibition on flight above 10,000' MSL (excluding airspace below 2500' AGL) in aircraft without ADS-B-out, even for aircraft without engine-driven electrical systems?

For example, does the FAA construe FAR 91.225 to prohibit a glider without ADS-B-out from exceeding 10,000' MSL, unless it is not above 2500' AGL?

If answering "yes", please provide specific examples.

For the purposes of this question, "aircraft without engine-driven electrical systems" means any aircraft that was not originally certificated with an engine-driven electrical system, that has not subsequently been certified with such a system installed, including balloons and gliders.

The motivation for this question is a conversation at a glider club where some pilots stated that their understanding was that gliders without ADS-B-out could not legally exceed 10,000' MSL, unless below 2500' AGL.

This related answer suggests that FAR 91.225(e)(2), which contains the prohibition on flight above 10,000' MSL for aircraft without engine-driven electrical systems, is best interpreted to only apply within the lateral boundaries of Class B or Class C airspace.

The current question is not about best interpretations of FARs, but rather about actual FAA practice.

Also, the current question is not about the significance of the phrase "without electrical systems" rather than "without engine-driven electrical systems" in FAR 91.225.  This letter of interpretation from the FAA Office of the Chief Counsel clarifies that the references to aircraft "without electrical systems" in FAR 91.225 should be understood to instead read aircraft "without engine-driven electrical systems", and that the omission of the phrase "engine-driven" was in fact simply a mistake.