texts:
Recently, the crew of an Indian airline performed a short choreographed dance sequence mid-flight on the occasion of Holi. This is, a not so rare practice amongst low-cost Indian carriers, who organize such dance sequences to celebrate special festivals (since festivals are a huge part of Indian culture, plus publicity for the airline afterwards).
Here is a YouTube video.

One of the pilots can be seen recording the dance on his camera.

SpiceJet specially planned this event, and had extra cabin crew on-board the flight as a precaution. Also, during the dance, one of the pilots was in the cockpit while the other one was outside, following standard regulations.
DGCA however, got wind of this, and turned out to be not in a very festive mood.

Mid-air Holi celebrations aboard eight flights have cost SpiceJet heavily, with the DGCA issuing show cause notice to the airline and suspending two of its pilots.

Here's another news link.
One of the arguments made by the DGCA was that this was dangerous to flight operations, and could have resulted in disaster had there been any emergency on-board during the event. Also, that this could result in an unruly cabin environment where in-flight safety of the crew and passengers would be affected.
Were the actions (suspension of pilots and showcause notice to the airline) justified? Is a dancing cabin crew dangerous to flight operations?


texts: What is the operating temperature of a turbo bypass engine, and how is it kept at that temperature?

texts:
What is the operating temperature of a turbo bypass engine? If advancements were made to materials through material science for the internal components would increasing the operating temperature result in better fuel efficiencies, better thrust and optimal engine performance?
How is the jet engine cooled to operate at the desired temperature?


texts: What are the pros and cons for "paying for your training"?  Specifically, there are companies out there that will sell the right seat for so many dollars an hour for those aspiring pro pilots to build hours.  Is this a bad thing?  Are there benefits to this approach.  Is it simply a function of the competition new pilots face (not considering the rumors of pilot shortages we are about to face)?  Is it unethical?


texts: Are all tires on an aircraft replaced at the same time?

texts:
On cars, it is often to replace all four tires at the same time. Is this true also for aircraft?

I imagine the nose gear and main gear probably can be replaced at different intervals. However, are tires within the same gear assembly replaced together? What about left and right gears? For example, is it ok to replace all tires on the left gear only while keeping old tires on the right?


texts:
When planes come off the assembly line at the factory, they're green:

So why are most painted white? Surely a darker colour would hide dirt better?

Is there a reason planes are traditionally white?

Here's a clip that shows a Boeing 747 being painted:


texts: Can you be a commercial pilot if you have a criminal record?

texts: Is it possible to become a pilot in the UK with a criminal record?


texts: Can time spent in consumer flight simulators increase the safety of flying light sports aircraft for licensed pilots?

texts:
I've asked this question to my flight instructor, who believes flight simulators do a very poor job of modelling flight physics for very light airplanes, which makes them useless for preventing accidents.

Considering most accidents are caused by loss of control this explanation does make sense. On the other hand, flight sims might help in dealing with engine failures.

I intend to fly in a plane derived from Zenair CH-701.


texts: Do airlines continue operating in the vicinity of a hurricane?

texts:
Have hung around some of the aviation interest groups (like airliners.net) and tried to research this but haven't found very clear answers.

Typically when a hurricane (tropical, peak wind-speed in excess of 100 mph) makes landfall, it sheds most of it's energy and water near the coast-line, however the rainfall and wind-speed heat-map (that is elevated beyond the seasonal average) may be over a very large area. Also a hurricane might move at a speed such that the weather conditions might change the large area (covered by the heat-map) over 2-3 days.

So, my questions in view of the above understanding are:

Whether normal flight operations continue (barring the to/from the airports that are directly under the hurricane path), in this vast other region that is part of the heatmap? (Say with airports in areas showing rainfall up to 3 inches, and windspeeds upto 50-60 mph.)
If commercial airlines do operate in such weather, what should I expect the ride to be like?
What are the chances of such flights being diverted?

Here is the WebCite archived webpage (so this link won't go away) of Weather.com that I am referring to.

PS. I plan to take a flight from Bangalore to Delhi to Kathmandu, on Monday, as the tropical cyclone (as it is called here in Indian subcontinent) is about to make landfall on the eastern coast of India around noon, and we are expecting upto 3 inches of rainfall and winds upto 60mph here on Monday morning.

I wanted to see if I should seriously consider rescheduling flights. A call to my airline customer-care yielded no useful information, and they seemed rather clueless. I read in the local newspaper that train services are being shutdown in the affected area, although it seems to be more like trains that pass through the area with the maximum impact.


texts: On a procedure turn, do you make the turn on the inside or outside of the procedure turn?

texts:
When flying a procedure turn like the one shown below, the first step is to fly outbound 039 degrees. When you turn inbound to 219 degrees, do you make that turn to the left or to the right? The left meaning to turn to the outside of the procedure turn (a greater distance from the FAF) and the right meaning to turn to the inside of the procedure turn (a shorter distance from the FAF).

If you look at these pictures, it looks like the procedure turn is made outwards from the course:


texts: Is this opinion on personal computer flight simulators too strict or is it actually true?

texts:
A couple of days ago I had a discussion with a commercial pilot and his opinion on personal computer flight simulators were a bit surprising to me.

He said that flight simulators, even with expensive payware aircraft are about as close to the real plane as Call of Duty to real warfare.

He said that most of the time the systems and the switches appear to look similar but key factors when operating those systems are missing, mainly because the manufacturer keeps those details more or less undisclosed. The developers don't even know what to simulate and it makes every single flight simulator just a simple game that bares a slight resemblance to reality but that's about it.

This surprised me to say the least, because I thought the well known, premium payware planes simulate the instruments and the systems very well and all the details regarding those systems are available in manuals that we can easily find online.

But I didn't really know that pilot well so I just accepted his answer, I didn't want to seem rude and try to debate him, but I'm very curious if he told the truth or he just tried to exaggerate. I'm especially skeptic about his comment on the undisclosed nature of flight systems.


texts: Why locate engines far from the fuselage in some aircraft, such as the SR-71?

texts:
There are some plane designs where the engines are placed quite far away from the fuselage, one example is the SR-71.

This amplifies the effects of any asymmetry of the engine thrusts, the worst case being zero thrust on one side. What are the reasons that justify or force those designs?


texts: What is the regulatory definition of AOG?

texts: What is the legal or regulatory definition of AOG (Aircraft on Ground)? For example, this is sometimes stamped on a repair order.


texts: What effect do slats have on descent rate?

texts: During descent, assuming the same speed and idle thrust, is the rate of descent greater in a clean configuration or with slats?


texts: I have an FAA ATPL based on a foreign ATPL, can I convert it to an EASA ATPL?

texts:
I have an FAA ATPL based on my Foreign ATPL. Am I now able to convert my new FAA ATPL to EASA ATPL? Of course with me doing all the exams etc..

or am I only allowed to convert my original foreign ATPL to EASA?


texts: How to find out if Restricted Area is "hot" before taking off?

texts:
For example, I often fly from KCHO to KOXB and almost always get cleared through R-4005 and R-4006. Occasionally they will be hot and I will have to go around, wasting time and fuel compared to if I had planned that route originally.

Is there anyway to call Patuxent Approach (or Washington Center) on the phone ahead of time to ask if the Restricted Area is hot?


texts:
In the context of aircraft autopilot design, I do not understand what is washout filter is [Heading Hold - Lateral Dynamics] and what is it used for.
May anyone explain to me?


texts: Is the Cirrus SR22T a turbo-prop? Or does in just have a turbocharger?

texts: Is the Cirrus SR22T a turbo-prop? Or does in just have a turbocharger like in a car?


texts: Would injecting water into a jet engine’s exhaust increase velocity?

texts: Can high pressure mist of water be sprayed into jet engine exhaust, to create steam, to increase velocity? Would the steam generated from high pressure water being injected into the jet engine exhaust increase velocity?


texts: Do the captain and first officer log the same hours for a flight?

texts:
On planes that have a captain and a first officer, how are flight hours logged and split between the two?

Are the hours split between the Capt and First Officer based on who is physically piloting the plane or are the same amount of hours are assigned to both?


texts: Is there a comprehensive list of IFR terms with definitions?

texts: Is there a comprehensive list of IFR terms with definitions easily available?  I am trying to make some flash cards for study


texts: Does an airfoil in potential flow produce drag?

texts: D'Alembert's paradox states that in a potential flow, the drag force is zero on a body moving with a constant velocity relative to the fluid. But what about pressure drag? Shouldn't there be drag from the pressure distribution around the airfoil? I have heard conflicting answers from multiple sources and I would like to clear up the confusion.


texts: What do "azimuth window" and "compass switch" refer to in this accident report?

texts:
I recently read the accident report on BEA 548, but I'm unsure of some technical terms used on p. 4 of the report (p. 14 of the linked PDF):

  Apart from the probability that in the particular conditions he would
  have elected to handle the aircraft himself, an examination of the
  lamp filaments in the P1 'azimuth' window showed that at the time of
  the crash the compass switch was turned to port, thus indicating that
  P1 was flying.

My question is:  What are the "azimuth window" and "compass switch" in this context?  Was the HSA Trident equipped with some sort of flight control transfer system between the P1 (captain) and P2 (flight officer) seats?


texts: Yet another "Why aren't I soloing yet?" scenario

texts:
Undoubtedly this question has been asked many times, but perhaps my situation is a little different than others. I'll try to be detailed but succinct:

I've accrued about 18.5 hours, 17.5 under the same CFI. I've checked off the 3 nighttime hour requirement (although my CFI said before my checkride we'll do more to get my nighttime pilotage skills improved), and 2 of the 3 required hours of XC, plus about one hour instrument time. Over the course of all this training time I've accrued 90 landings (my CFI loves touch and goes and we can do 10 landings in little over an hour). Yet still I'm not ready to solo. Now, I know I'm not the most proficient pilot he's seen, and perhaps I'm just average among the overall population, but 90 landings, and not including the hundreds of landings I've done on my simulator and countless hours around the patterns of my local airfield? Rarely do I have a hard(er) landing and some downright kiss that runway on or near centerline. Here's the other compilcation: My CFI is a one-man shop with his own planes, has logged 18,000 hours in his career and is a lifelong instructor, about 29 years experience as a CFI. If my CFI was part of some instructor mill at a flight school, I would certainly consider walking away or having a serious discussion with him at this juncture. However, since I respect his seniority it's creating a lot of cognitive dissonance. Am I missing something? Another little twist: he says I'm on a trajectory to be one of his 45 hour and done students (he has numerous students done in under 50 hours and an extremely low failure rate), so perhaps he's one of those people who solo people later after making sure things are absolutely positively perfect? Has anyone had an instructor who went about the process in this manner?


texts: Could a knowledgeable passenger have saved Helios Flight 522?

texts:
Helios Flight 522 crashed when the crew unknowingly suffered hypoxia. Although the masks in the passenger cabin deployed, the crew were unaware of this and didn't realise the extent of the problem.

If I was a passenger on a plane at cruise altitude and the oxygen masks deployed, I know that there is only about 10 minutes oxygen available. I would expect the plane to immediately descend to a lower altitude.

If I don't notice any change in attitude and there is no passenger announcement after a few minutes, would it help to alert a flight attendant to check that the pilots are aware of the issue? Or would it be best to assume that 'they know what they are doing' and just keep quiet?


texts: What are the requirements for aircraft marker cones?

texts: What are the requirements on aircraft marker cones (a.k.a. safety cones) according to IATA IGOM-96, i.e. size & weight?


texts: What is the answer to this question about aircraft position based on an NDB?

texts:
An aircraft is intending to track from NDB ‘A’ to NDB ‘B’ on a track
  of 050° (T), heading 060° (T). If the RBI shows the relative bearing
  of ‘A’ to be 180° and the relative bearing of ‘B’ to be 330° then the
  aircraft is:

  A. Port of track and nearer ‘A’
  B. Port of track and nearer ‘B’
  C. Starboard of track and nearer ‘A’
  D. Starboard of track and nearer ‘B’


texts: Does the autopilot attempt to recover from a mechanical failure of a single control surface?

texts:
I'm asking this question having watched a documentary about Northwest Flight 85 in 2002, during which a 747-400 experienced a lower rudder hardover at an angle of 17 degrees to the left.

The pilots were able to recover by taking over manual control and using the ailerons, the upper rudder and asymmetrical engine thrust to oppose the forces being generated from the lower rudder hardover.

During the doco, I believe the pilot in control immediately turned off the autopilot as he realised it wasn't going to be able to recover from the initial roll.

I just wondered if an autopilot would be able to recover from such an event - i.e. is it technically possible? It seems like the sort of thing an autopilot could achieve easier than a pilot, assuming it was programmed correctly.


texts: Why are cockpit voice recorders limited to 2 hours recording?

texts:
With today's technology in memory storage, where simple voice recorders can record virtually endless durations, why are CVRs limited to only 2 hours. Is it the eternal "cost vs benefit" reason?

Wouldn't more recording provide greater insight to investigators in case of any disaster?


texts: So the 1500 hour legislation was set to expire on the 30th of September 2015. Anyone know the outcome of the expiration. Did congress extend the rule, or is it no longer in effect. I tried searching the web but couldn't find any info.


texts:
Is it possible to rent a float plane with a private pilot's license?

Flying floats is one of the main attractions for me to learn to fly.  However, after some searching on the internet I can only find wheeled aircraft that are available for rent in my area.  Am I missing something?  Are there flying clubs or partnerships that have float planes available?  I would love to fly floats but owning a seaplane is not in the cards for me at this point in my life.


texts: How to determine the thickness of an airfoil?

texts:
In calculation or designing, how to determine the airfoil thickness? What is the guideline or consideration in designing airplane's wing? We all know that the bulge (the ticker in the airfoil) is required to apply Bernoulli principle, to create low pressure above the wing. But how to bind the round nose shape requirement to the design requirement. In this case, to make the airplane to be efficient (especially related to the power consumption).

This airfoil is required for an airplane as I explained here. Maximum weight will be 400kgs, and the maximum speed will be 200km/h.


texts: At which point in scale reduction do slats and flaps become unnecessary?

texts:
Imagine some Fi-156 Storch, and reduce its scale down gradually to 10cm span. Let's assume full scale Fiesler Storch is 100% efficient at, for example, minimizing stall speed.

During this reduction process, if every dimensional element is scaled down perfectly, except airfoil shape, slats airfoil shape, flaps airfoil shape, and slats and flaps relative gap width between them and the wing, how would these (allowed to vary along vertical axis) parameters roughly evolve during scaling down process, so that this aircraft ability to minimize stall speed remains close to 100%? Is there in this case some linear pattern along Reynolds number variation?


texts: Is an "atmospheric geostationary satellite" feasible with current technology?

texts:
Meaning by "atmospheric geostationary satellite" a vehicle capable of hovering 30 km above Earth surface, hence insde atmosphere, for unlimited time, making use of air propellers, solar panels and batteries.

How much energy is needed to keep an object steady in air at 30 km above surface?

There are two possibilities: a plane-like vehicle, flying in circle, using wings to stay up; an helicopter-like vehicle, hovering.


texts: What practical alternatives are there to 100LL in 2021?

texts: As a prospective student pilot in Southern California, I would like to avoid 100LL. Since the FAA 100LL phase-out is stalled, what other alternatives are there? Continental has a line of Diesel engines such as the CD-135, are supplemental type certificates available / retrofits common? What about "mogas?" Does the answer change if someone is looking to purchase an aircraft?


texts: What is the difference between mist and haze in terms of relative humidity?

texts: I am an aviation meteorologist and I struggle to distinguish the two of them.


texts: I have an older VAL 760 TSO COM radio. Twice now the radio has blown an internal radio fuse on transmit. VAL has tested and certified the radio as "Good", but advice that the cable or antenna could be faulty. How does one test that the antenna or cable is adequate? Can one use an ohm meter to check for resistance or continuity? Any other advice is appreciated. I have a newer VHF antenna. It may be a CI-101, although not positive.


texts: Why is the Eurodrone (MALE RPAS) equipped with turbo props in pusher configuration?

texts:
https://upload.wikimedia.org/wikipedia/commons/thumb/9/9c/EuroMALE_ILA_2018_%2801%29.jpg/1920px-EuroMALE_ILA_2018_%2801%29.jpg
Why is the Eurodrone (Medium Altitude Long Endurance Remotely Piloted Aircraft System - MALE RPAS) equipped with turbo props in pusher configuration?
What are the advantages/disadvantages?


texts: Has a C-130 ever been designated as "Air Force One"?

texts: Near the end of the movie, "Air Force One", Harrison Ford is transferred to a C-130, which then changes its call sign to "Air Force One". My question is, has a president of the US ever flown in a C-130 while in office?


texts: What are the ANT and ADF modes on an NDB receiver?

texts:
I am seeing this in a simulator, so I don't have a manual for it…
On the Bendix King KR87 NDB receiver, the leftmost button labelled “ADF” switches an indicator above it from “ANT”

to “ADF”

When pushed, the needle on the direction indicator indicates towards the NDB (if in range). When popped, it does not, at least for the NDB stations.
So I am wondering, what does this switch change and why it is needed?
(screenshots taken from FlightGear simulator by me)


texts: What does the difference between a 'Mechanical Engineer' and an 'Aerospace Engineer' who both work on planes? Does one focus more on something than the other?


texts: How IATA Code is requested or assigned to an newly built airport ?

texts: We have an upcoming airport in our state. An ICAO code is already in place but who and when will the IATA code will get created ?


texts: Why must a pilot enter "Upwind" when entering the traffic pattern for RWY 9 at Linden (LDJ) airport in New Jersey?

texts:
The chart supplement procedures require aircraft to enter the traffic pattern "Upwind" for Runway 9 at Linden (LDJ) airport in New Jersey.

Question: Why is this required?

Chart Supplement:

New York Terminal Area Chart cutout showing Linden airport:
link to chart

Picture of "Upwind" leg from the Aeronautical Info Manual:


texts: What happens when a takeoff clearance is cancelled by the ATC?

texts:
Let's say an commercial passenger jet is accelerating down the runway, taking off. The ATC receives some signal that he/she should cancel all takeoff clearances.

Exactly what happens in the control room?
What does the ATC do and how does he/she make sure pilots understand the cancellation?
How do the pilots in the aircraft taking off respond? Are they trained for this scenario?
Is a takeoff cancelled even after V1?


texts: Is there an alternative (more robust) operating law/setting for jet-engines? After one engine failed?

texts:
Sorry for the complicated Question.

I was wondering (after reading this report) if a two-engine air plane has an alternative operating scheme/setting for the remaining engine. Maybe a setting which is not that fuel efficient but more stable with respect to compressor surge and stall.

In the cited report one engine suffered compressor stall (maybe by bird-strike) and was subsequently shut down. The other engine was reported to have left a trail.


texts: What are these blades on the engine cowling of a Wittman Tailwind?

texts:
The Florida Air Museum in Lakeland has a Wittman W-8 Tailwind with four wooden, propeller-like blades on the engine cowling:

Source: own work

What are the blades for? It's an experimental aircraft so it's possible that they're unique to this specific airframe.


texts: Why do I see moisture coming from the middle of the wing as well as wingtip vortices?

texts: A lot of times I see small tube like streams of visible moisture training from the middle of an airliners wing. I assume this is induced drag created by wingtip vortices, when the aircraft is heavy, clean, and slow. However, I figured this would only happen at the “wingtips” and not from the middle section of a wing. I have seen them at the wingtips but a lot of the time it’s coming from the middle. If this is from the wingtip vortices how come they would come from the middle?


texts: At what position or distance from an airport are you considered to be in the "traffic pattern"

texts:
image source

In the United States, as an aircraft is approaching or departing a
non-towered airport, at what position or distance from the airport
are you considered to be in or out of the "traffic pattern".
Is it different for an airport with a operating tower?
Does it vary with other countries?

Hint: a regulation exists but it is not in part 61 or 91 (think, space shuttle)...


texts: What causes lift in aerofoil: Bernouli's principle or Newton's third law?

texts:
Reading materials online, I observe some explanation based on Bernoulli's principle, quoting the difference of air pressure above/below and difference of speed of airflow. While some say's Bernoulli's principle works only in special conditions (laminar, non-viscous, non-compressible, streamline, etc.) and the correct working is based on Newton's third law whereby, the airfoil pushes the stream downward and experiences lift upwards.

Bernouli's principle is also said to not work for symmetrical aerofoils and inverted aerofoil.

What is the final verdict of what causes lift?


texts: Are ICAO and FAA airport signs and markings the same?

texts: Are ICAO and FAA airport signs and markings the same or are there differences? If so what are the differences?


texts: What are the effects of the Boeing 787's very flexible wings?

texts:
I recently came across this picture of the Boeing 787 series aircraft's incredible wingflex:

I suppose this is a consequence of using very light CFRP wings, but how does the wingflex itself improve the 787's flight performance? Do the benefits/drawbacks also apply to the 747-8 (which IIRC also uses CFRP wings)?


texts: Is there an aerodynamic reason why the concept of biplane or triplane has been completely abandoned? Practically all planes were biplanes in WW1, and in WW2 practically none were developed.


texts: Does the EASA/FAA require additional life vests, and life vests for infants/children?

texts: Is there some requirements (EASA or FAA) for additional life vests, and life vests for infants/children on-board estimation?


texts: Will landing gear with wheel fairings keep spinning due to airflow?

texts:
I asked this in a side note to a previous question, but I figured it warranted its own question.

If a fixed gear aircraft is fitted with wheel fairings, even if you tapped the brakes after lift-off, would the wheels start turning again? With typical wheel-fairings I guess about one third to one quarter of the tire sticks out into the oncoming air flow, and would face perhaps 120 kts wind. All aircraft tires I've seen have grooves running along the direction of travel, with nothing going sideways that would be any obvious wind catcher, so I guess they're pretty much slicks in this regard.

Or would any 'normal' amount of friction in the bearings keep them from turning?


texts:
This is funny!
Please post jokes, pictures, cartoons, videos related to pilots, air/ground controllers, aircraft mechanics, flight/cabin/ground crew or anyone/anything related to aviation.
Rules

Any material should not be offensive, rude or insulting to any group.
If that material requires proper attribution, please verify that by posting it here, no copyright rules are being violated.
You can add your own personal story as a joke. However, this is not the Aviation Blog. We are quite active over there and will be very happy if you want to contribute. Please come visit the chat room Readback, and ping the owner of the room for permissions.
This post is not for rep generation, hence all posts should be wiki. Mods are watching, and one of them has a cattle prod (yes, the electric one).
The material you are posting should be strictly related to aviation.
Make sure that the post is readable, and properly formatted.
Brevity is a virtue.

Please remember:
Before flagging it as off-topic, or too broad, or low quality (really, doesn't that depend on you), please refer to this discussion behind the motive of this post. More information is present in the links in that question and the comment which follows.


texts: Why do we need to fly at lower altitudes at night to prevent hypoxia?

texts:
FAA recommends general aviation aircraft to stay below 5,000 ft at night time.
I thought the reason is that oxygen usage with our eye's rods since the rods uses much oxygen and rods can get hypoxia which makes tunnel vision and eventually not able to see outside.
But one of my friends claimed the reason why we are supposed to fly at a lower altitude to prevent from hypoxia is that at night there is higher pressure near the ground which makes fewer air molecules at high altitude at night than daytime.

Is this true that we get hypoxia more easily at night time because of pressure and that's the reason why FAA recommends us to fly below 5000ft?
If the question number 1 is not true (from my understanding), is rods problem the only reason why FAA recommeds us to fly below 5000ft at night time?


texts: Calculating CL and CD from Cp vs. x/c graph data?

texts:
I need to calculate CL, CD, CM coefficients for NACA 0012 airfoil at angle of attack 6 degrees and Re=7.5e5, Mach=0.05. I used Xfoil for getting the CP distribution, Cp vs. x/c graph and Cp-x-y data. With Cp-x and Cp-y data points I tried to calculate CL and CD values with a matlab code with equations given below;

I integrate the CP-x, CP-y points which executed with XFoil respectively to getting Cx and Cy. I used trapz command in matlab to integrate these points. However at the end of my calculation matlab code was found that CL=1.1936e-04 and CD=0.7249. However at the graph screen of XFoil CL and CD was different.

I can not understand that if the problem was about my solution method or my matlab code? How can I get the  coefficients with Cp distribution?


texts: What precautions should I take when flying over a mountain?

texts:
I would like to go on a photo flight over Mt. St. Helens sometime while I'm in the Portland area.  I am aware of the weather conditions that are caused by mountains - but what precautions should I take to make sure that my flight over the "summit" is as safe as possible.

I think it's worthwhile to mention that there is a wilderness area over Mt. St. Helens, so I will be above 2000ft AGL.


texts: What typical improvements in lift/drag are gained using dimple & zig-zag strips?

texts:
A golf ball goes twice as far using a dimpled surface. Many European aircraft (especially gliders) use dimple strips or zig-zag tape on propellers, wings, struts etc. Very few US aircraft use these products.

The dimples/holes/perforations are sometimes mechanically stamped onto a part, but more often a metallic or fiber tape is applied to a thick part of the surface. This is using existing after market technology and has nothing to do with "blow holes".

This question is not how it works it is HOW WELL it works!

What typical improvements in lift/drag are gained and are there any drawbacks to their use?

Dimples on golf ball reduces drag and doubles its range.

Dimple perforations or strips and zig-zag tape decrease drag on some aircraft surfaces.


texts: What are these hooks and tassels on the nose?

texts: What are the hooks and tassels hanging down from the nose of this aircraft?


texts: Can you become a CFI with only a PPL (EASA)?

texts:
In Europe, can you get your CFI rating with a PPL only or do you need a CPL?

I assume that if you get paid to do flight instruction it's considered a commercial activity, so you'll need a CPL. But what if you do instruction without getting paid, do you still need a commercial licence to be a CFI?


texts: In an airplane wing, which control surfaces are primary, and which ones are secondary?

texts:
I got this device detail of a wing. Those parts are:

1: wingtip fence, one of the wingtip device beside winglet.
2 & 3: aileron.
4: flap track.
5 & 6: slat.
7 & 8: flap.
9 & 10: spoilers.

2 & 3, 5 & 6, 7 & 8, 9 & 10, are part of controls.

In controlling an airplane (if it really has that pairing devices), if we have to use them one after another, which one is said main (primary) and which is secondary?


texts:
$V_r$ is the speed at pilot should initiate rotation on take-off and $V_2$ is the safe climb-out speed. Pilots determine them for each take-off by looking them up in a table in POH or QRH or somewhere.

But somebody had to fill those tables in using flight tests and calculations. What are the criteria by which the values are selected?


texts: What are the advantages of more than 4 propeller blades?

texts: I have heard that propellers with more than four blades are not as efficient as 4 or less blades because of lower thrust which may result from interfering prop-streams. But I see the ATR-42/72 and they have 6 blades. What is the reasoning and the advantages to that prop layout?


texts: A friend of mine sent me this picture, which Is somewhere in Miami. But I don't seem to recognize it


texts: How does the Boeing 777's yoke of both the captain and the first officer have synchronized movement?

texts:
On Airbus planes, the side stick of both the captain and co-pilot are not synchronized in movement, meaning if you the captain moves the side stick, the co-pilot's side stick will not move together. If the co-pilot moves the side stick while the captain does, it will be a dual input.

However, on the Boeing 777 is also a fly-by-wire(FBW) design. But if you watch a 777 cockpit during flight, both of the captain and the co-pilot's yoke moves.

How is that done? Are both of the yokes connected by one mechanical system, and that mechanical system feeds the pilot input to the conputer? Or is it done electronically, with motors or other stuff?


texts: What are the highest temperature locations in the outer shell on an aircraft engine? Particularly, modern turbofans like the Trent 900 for example. I'm interested in the temperature constraints of pylons that's why.


texts:
I'm merely an amateur simulator (X-Plane) pilot. On a flight yesterday the airspeed indicator stopped working. After the initial panic I remembered reading something about pitot tubes freezing, found the pitot heating switch, and turned it on. The problem was resolved immediately.

This led me to think: Is there a good reason to not turn pitot heating on before take-off, and leave it on for the entire flight?

I'm flying a Sud Aviation SE 210 Caravelle


texts: How is the search-and-rescue system for civil aviation over waters agreed and funded?

texts:
Several accidents in the recent years have revealed how important --and intuitively expensive-- SAR operations over seas can be.

Need for daily government agencies / military flights in the first weeks after the accidents, need for underwater search.
SAR managed by other countries than the registration country of the aircraft.

Crewmembers of an Indonesian Air Force NAS 332 Super Puma helicopter over the Java Sea, Indonesia, 2015.Source

Without entering into too much details:

How is SAR for civil aircraft agreed globally?
Is that under ICAO umbrella?
Is it shared with maritime SAR or other organizations?
How is SAR responsibility shared between countries worldwide?Is a map with responsibility boundaries available?
How is SAR funded?
Are operators (their insurances) liable for costs?
Is it a service provided for free, if so to which extent?
How is the decision to stop active search taken?


texts: For light, GA aircraft, is there a "standard" turn, and what does that mean?

texts: I have seen instructional sites that seem to indicate a 15 degree bank is a standard turn.  The Turn Coordinator has 15 and 30 degree marks on it.  Is 15 degrees a standard turn and what does this mean?  Is there a general way to figure out what the radius of such a turn is or how long it would take to fly a circle at 15 degrees bank?  Without trying to do the math, it seems that airspeed together with bank angle would determine the turn rate.


texts: Are there any studies on the safety of glass versus steam instruments?

texts:
Has anyone come across any academic study on the effects of information provided by "glass" instrumentation that affects, favorably or unfavorably, situational awareness, skill and performance, and decision making?

Related question: Where does the term 'steam cockpit' come from?


texts: What twinjet with rear-mounted engines and swept wings did I see in Savannah, GA?

texts: I saw this flying in Savannah, GA and need help identifying it. It looks like something military due to the color and lack of markings. Can anyone help?


texts: Why is the pilot in this video retracting the spoilers so shortly after landing?

texts:
I watched this video (link with time) and wondered why the pilot has retracted the spoilers so shortly after landing.

Because the runway is wet and it looks like the plane is still quite fast even in slow motion. Wouldn't it be better to have more braking grip?


texts: Why are private jets more expensive to travel in than commercial aircraft?

texts:
I am not sure if this is the right site for a question that asks about the economics of aviation rather than the technical aspects of it, but I couldn't find any other stack exchange site so I am asking this here.
As far as I understand, the reason why commercial aircraft are cheap to travel in is because the operational costs of the aircraft are divided among the many passengers in the flight. A fair share of the maintenance costs come from depreciation of the aircraft and the engine overhaul and inspection. In a business jet, I would assume the cost of fuel and the landing fees are much smaller than that of commercial aircraft and, as a result, do not add much to the cost per seat (since the costs are proportionally smaller - approximately at least). So I suspect that costs such as engine overhaul and aircraft inspection do not scale with aircraft size and are approximately the same for both business jet and large commercial aircraft. As a result, the price that each passenger has to pay is much higher.
I tried looking for a few sources on the internet that confirm this but couldn't find any that show a detailed account of expenses. If this hypothesis is correct, I would appreciate it if you could direct me to a source that compares the operational expenses of any commercial aircraft with a business jet.
So is it safe to say that travelling/ transporting cargo is cheaper in a large aircraft than a smaller one if the fuel efficiency is comparable?


texts: What measures can the aerospace industry take to deal with changes in the electronic industry that are incompatible with its own conservatism?

texts:
The development of computer flight systems is characterised by lengthy certification processes, exceptionally rigorous testing regimes and a default position of extreme caution.

A change in any component at any layer in the hardware/software stack could introduce new incorrect behaviour. For example, microprocessors are so complex that different manufacturing revisions of the same model can introduce bugs.

As a result, these systems are very tightly specified at all levels and very slow to change, so that many systems still in production use what in most other contexts would be considered obsolete technology.

CPUs such as the 68040 and 80486 (both introduced around 1990) were designed into systems a quarter of a century ago that are still being produced today.

Summary of the problem

The pace of development of the electronics industry has accelerated hugely since the first generation of computerised flight control systems were introduced in the early 1970s, and is becoming increasingly incompatible with the needs of the aviation industry. It means that for example:

Devices now have manufacturing lifetimes of just a few years (compared with several times that a few decades ago).
Devices are now intended to have much shorter service lives than they used to (by orders of magnitude).
Increasingly tiny widths in microprocessors mean they succumb increasingly early to problems such as oxide breakdown.

Aerospace represents a very small portion of the manufacturers' business: their main customers make consumer devices, and have utterly different demands on the electronics industry from those of customers in aviation.

Research into the issue

These and other issues are outlined in some detail in Microelectronics Reliability: Physics-of-Failure Based Modeling and Lifetime Evaluation (and no doubt elsewhere - this was just one I found while trying to answer my own question).

The Aerospace Vehicle Systems Institute (AVSI) Consortium Project #17 Methods to Account for Accelerated Semiconductor Device Wear Out has attempted to quantify these risks.

The question

What can the aerospace industry do - or what is it already doing - to mitigate the problems and risks this poses?


texts: Why do low wing aircraft have higher dihedral than high wing aircraft?

texts: I have noticed and read in books that low wing aircraft have higher dihedral than high wing aircraft. Dihedral is design feature for lateral stability so should be needed for both designs. So why is it more pronounced in low wing designs?


texts: Is it theoretically possible to create an aircraft like this?

texts:
I was browsing through some funny airplane pictures when I came across this. An airplane with the engines replaced with the cockpit and the cockpit replaced with a huge turbofan.

I was intrigued by this idea, but then it also brought up the question: Is it theoretically possible to create an aircraft like this and be possible for the aircraft to take flight? (as in fly in the air for prolonged time)

Source: YouTube


texts: Would a flight consisting of solely first-class passengers be cancelled due to center-of-gravity issues?

texts:
Consider any modern jetliner (narrow-body and widebody separately) in a standard 2 or 3 class configuration. If somehow only first-class or business-class passengers bought seats, would that plane be impossible to fly because all the weight is focused up front? And since they are premium-class they can't be moved aft for load-balancing.

If this is (practically) impossible, then doesn't that suggest there is a minimum number of economy passengers required as "ballast" for every premium passenger?

I suspect one answer might be that the flight wouldn't be profitable anyway with few-to-none economy seats sold, so it would be cancelled. But let's suppose in that case the aircraft needed to be flown anyway because it was required to be at the destination airport, profitably or not. Doesn't that suggest there is a maximum "premium-only" passenger count that would actually be less than the number of premium seats? I.e they would have to tell some premium passengers "sorry you're bumped, or you can go to economy" despite the plane being 80% empty?


texts: What is this object on the tail of an F-16?

texts:
Source: skytamer.com

What is the object on the tail of this F-16 (next to the serial number)?


texts: Can we show through simple geometry rather than formulae or graphs that the best glide ratio occurs at the maximum ratio of Lift to Drag?

texts: For an unpowered glider, can we show through simple geometry involving force vector diagrams, rather than mathematical formulae or graphs, that the best still-air glide ratio is achieved at the angle-of-attack that gives the maximum ratio of Lift to Drag?


texts: Are nuclear bombers themselves damaged after dropping bombs?

texts: Shock waves resulting from low intensity explosions can easily reach 10,000m/s.  About 5% of the energy released in a nuclear air burst is in the form of ionizing radiation: neutrons, gamma rays, alpha particles and electrons moving at speeds up to the speed of light (thus, carrying a hell of a lot of energy).  With these stats it appears that for the bomber as well, a nuclear bomb is very bad. How are they protected?


texts: Does the dew point affect density altitude?

texts:
I am looking for the most accurate formula to calculate the Density Altitude (DA) to use it for calculating aircraft performances during landing.
Now I found the following formula:

DA = PA + [120*(OAT - ISA temperatures at given altitude)]

PA = ((standard pressure - given pressure)*30) + field elevation

My question is: Why is the dew point not included in this formula and what influence does it have on the density altitude? What is the correct formula with dew point included to calculate the DA?


texts: Can multiple helicopters be used to lift a heavy load?

texts:
If the load is heavier than a single helicopter could lift, how possible is to use multiple helicopters for this task?

I have only seen this in some movies. The biggest doubts are

If we attach two ropes to the single point of the load in a V shaped way, a side force will be created pulling the helicopters together into collision.
Even without this, the flight of the two machines probably needs to be very coordinated.

In movies like "Pacific Rim" a whole swarm of helicopters lift a heavy robot. How realistic are these visions?


texts: Is it normal to be scared of flying before becoming a pilot?

texts: Are there any studies that have researched into fear of flying when not in the cockpit? The question arises from the fact that for some reason, I have found myself to be scared when on a plane as a passenger, but when at the commands the situation is totally different. This applies also to a lot of people when driving cars for example. Is this a normal human behaviour?


texts: What are the rules for close/formation flying of civilian planes?

texts:
Two recent questions and their answers have raised a further question.

In Are there laws about how close military aircraft can fly to passenger jets, and are they enforced?, we learned that "the military can get as close to other aircraft as they damn well please, through a procedure called Military Assumes Responsibility for Seperation of Aircraft, or MARSA".

In Why are there NASA branded F/A-18s? we see a picture of closely flying planes, and a comment notes "NASA is a civilian agency".

Do the NASA planes fly under MARSA rules or another set of rules for civilian agencies?  Are there other non-military agencies that fall under this rule too?


texts: Are fixed wing aircraft with gimbal thrust feasible?

texts:
Elon Musk has suggested that he'd look at implementing VTOL electric aircraft with a "gimballed thrust" system similar to the one used in rockets.

  Aircraft have all these unnecessary things like tails and rudders and elevators - not needed. Just gimbal.. anyway.. gimbal the electric fan. For some weird reason gimbaling motors is normal in rockets and not in aircraft. Why not? [Do you have specific plans?] I've been sort of toying with the design for an electric supersonic vertical take-off and landing electric aircraft for a while, I'd love to do it, but I think my mind would explode

What are the challenges to implementing this? Is it technically feasible?


texts: What is the temperature of the brakes after a typical landing?

texts:
On an airliner, what is the temperature of the brakes after a typical landing, and how long does it take to cool down?

Is it hot enough that mechanics should wait before servicing an aircraft that has just touched down minutes before?


texts: Do rotorcrafts like helicopters have autopilots?

texts:
Years ago, I had the opportunity to board a Bell 407 for a long distance flight and put every question related to helicopters that crossed my mind to the pilot when we were forced to land due to visibility issue and also while we refueled.

I realize now that I've missed something important: do rotorcraft including helicopters have autopilots like fixed wing aircraft do, or is that ruled out due to their peculiar flight mechanics?


texts: So, I went online to search for the 737 FCOM, but I can only get the FCOM from 2005. Is there a 2019 version? An updated version?


texts: Is a non-WAAS Garmin 530 certified for an LNAV/VNAV approach?

texts:
I may not understand all the details of what I'm asking but trying to wrap my head around it.

I am aware that before WAAS, some GPS aircraft were equipped to get vertical guidance by a Barocorrected altitude information sent to the FMS and along with the non-waas GPS could calculate (interpolate) glide path info and were approved to fly LNAV/VNAV approaches.

My question is whether the non-waas Garmin 530 has the ability and necessary FAA approval to perform this and if it is an option?


texts: What to do as an international student without a driving license that is needed for PPL Training in Germany?

texts:
I am required by the Luftamt Südbayern to provide information from the driving suitability register from the Federal Motor Transport Authority in Germany but I do not have a German driving license as I am an international student.

Anyone with any ideas as to how I should approach this?


texts:
Having recently learned that 155 mm ramjet artillery shells are now a thing, I wonder how much ramjet engines can be miniaturized. Could we see ramjet tank shells? Man-portable recoilless guns? Shotgun shells? Rifle bullets? For less martial applications, could we see micro-ramjet engines for small drones, similarly to micro-jet engines? (Whether or not it would actually sell if built is out of the scope of the question, let's simply imagine that there is a market for ramjet-powered microdrones.)

Given current (or near-future) manufacturing techniques, what would be the limiting factor for ramjet miniaturization? What would be the performances for the smallest engines, and how difficult/expensive would it be to make them? Are there theoretical physical limits to the minimal size of a ramjet engine?

Note: this ramjet-assisted shell is probably using solid fuel, but limitations for liquid fueled ramjet specifically are also relevant.


texts: Why can't lifting line model be applied to yawed/skewed/oblique straight wing (low M)

texts:
If all the horseshoe vortices have skewed central bound vortices on the same skewed 1/4 chord line, then the trailing vortices from the downwind half span  of the wing induce less on the windward halfspan and vice versa. So then the windward halfspan of the wing will have increased angle of attack and lift vs unskewed and the leeward have less.
But I gather this is the wrong result vs experiment? Please don't confuse the issue with symmetrical swept back wings. No, I  used Lifting Line to generate results that disagree with experiments for asymmetrical oblique or yawed straight wings? What am I overlooking ?


texts: What can passengers do if they realise their plane is not on the right path?

texts:
In the case of flight MH370, I think passengers on board would have long enough time to realise that something is wrong with their flight. I have a habit of carrying a compass with me when I travel abroad. If the plane is not heading in the general direction towards its destination once it reaches cruising altitude, then I would be worried. This is especially so for passengers on board flight MH370 when it appears that it is flying in the opposite direction for a very long time.

What can a passenger do if he realises that the plane is not flying in the right path, i.e. a possible suicide mission or hijack?


texts: F/A-18E and F/A-18F Rhinos: What's the difference?

texts:
The answer to this question seems intuitively obvious: One is a single seat strike fighter while the other has two crew stations.  But is that all?

When it was under development I judged that the E variant was an upgrade designed to replace legacy F/A-18s in Navy and Marine Strike Fighter squadrons (the Corps ended up never buying the jet and held out for a newer design) while the F variant was intended to be a multi-role replacement for both the duties held by the F-14 and the A-6 aircraft, while providing a optional arrangement with dual flight controls for training.

But from the NATOPS manual as well as other literature on the Super Hornet, it appears that the aircraft are one in the same, save only for the second crew station.  Does anybody know specifically why the USA purchased x number of E models to equip specific strike fighter squadrons (eg VFA-14) and y number of F models for others (eg VFA-2)?


texts: Why does the F-35 Lightning II have only 1 crew when the F/A-18 Hornet had 2?

texts:
Many successful fighter aircraft, eg F/A-18 Hornet, have 2 crew (pilot and navigator), which (from my albeit limited research) gave great benefit in complex situations especially involving ground defences.

The F-35 Lightning II is supposed to be multi-purpose, but has only 1 crew - why?

Do the advanced electronics compensate for the lack of a navigator?
Would the design (aerodynamics/frame) be compromised by adding another seat?
Something else?


texts: What is the optimum speed for takeoff flaps?

texts:
I took a 737 rating written test yesterday and one of the questions was:

What's the optimum speed for takeoff flaps?

V2
V2 + 10
V2 + 15
V2 + 20

Anybody knows the answer? I did some research and couldn't find it.


texts: Am I expected to stay on glide slope for landing in a light aircraft?

texts: When I land the airplane (Cessna 172, 182, 152) I notice that I come in pretty far above glide slope (four white lights on the PAPI).  I pick an aiming spot on the runway (like the second center line stripe) and maintain my approach airspeed while flying towards that point.  I'm able to reach that aiming point with quite good accuracy and land the plane smoothly and softly, but I'm above glide slope for most of the approach, and then on short final the white lights start to turn red.  Clearly my approach is steeper than the usual 3 degree glide slope.  I thought that's what flaps were for - to allow for a steeper approach.  Am I doing this wrong?  Should I focus on staying on glide slope, or should I focus on my aiming point?  I've had several flight instructors and most of them have never said anything about this.  I kinda like being a little higher, and approaching exactly on glide slope usually means I have to add power on short final because I start getting too low.


texts: What is the lump on top of the Boeing 737?

texts:
What are the lumps (Circled) on top of these two Boeing 737s? I looked it up but I only found the answer for one specific Virgin Blue 737.

Original image source


texts: How much maintenance time did it take to make an F4U Corsair ready for another flight?

texts:
A coworker I worked alongside once told me that during his time in the Navy, he was responsible for taking care of maintenance on F-22s. He stated that every F-22 required 10 hours of maintenance for every hour of flight.

I am curious how this level of maintenance stacked up against older less-modern aircraft. For the sake of narrowing it down, let's take the F4U Corsair as an example. Assuming a routine flight (training or simply air-patrol), what was the amount of time that would be required to maintain the aircraft on the ground to keep it safe for its next flight? 1 hour? 2 Hours?


texts: May pilots receive compensation for performing preventive maintenance under US regulations?

texts:
Under FAA regulations, I know that at least a private pilot certificate must be held in order for a pilot to perform preventive maintenance on an aircraft.
May a pilot also get paid by someone else for performing that maintenance, and does the grade of pilot certificate make a difference? For example, is there a requirement to hold at least a commercial certificate to be compensated for the performance of preventive maintenance, or is preventive maintenance solely to be considered an incidental, non-compensatory privilege of any pilot certificate holder of private or higher grade regardless of that grade?
This hypothetical scenario is with the assumption that this is freelance and has no oversight by a certified mechanic. An example could be a fellow pilot casually offering to change your oil or replace a lightbulb for some monetary labor compensation.


texts: What happend to the airframe of the Aloha Airlines Flight 243?

texts:
What happened to the airframe of Aloha Airlines Flight 243, after the explosive decompression?
I know that the structures were studied for a while after the aircraft safely landed in  Kahului Airport, but what happened after that?


texts: How many type ratings are pilots allowed to hold at once?

texts:
I think i've read that the B787 has a common type rating with the B767 and B777. But I also think I've read that pilots are only allowed to fly two types of aircraft at a time...

So when they go to fly the 787, do they have to give up one of the their ratings if say they were previously allowed to fly the 767 and 777? Would the same still apply for say a B757 and B767 which have very similar flightdecks?

EASA and FAA perspectives would be appreciated :)


texts: Why did BA 199 fly a missed approach followed by circles?

texts: I just saw G-YMML (operating as BA 199) execute a missed approach and make weird circles. What is happening here? (FlightAware permalink)


texts: Denver International Airport pneumatic tube systems

texts:
Wikipedia says:

  Denver International Airport uses many pneumatic tube systems, including a 25 cm diameter system for moving aircraft parts to remote concourses, a 10 cm system for United Airlines ticketing, and a robust system in the parking toll collection system with an outlet at every booth.

Note: No citation, and I can't find any reference to it on the web.

Question: If these systems actually exist, what are their total lengthes (eg. 35 km total) and usage rate (eg. 7000 objects per day)?

References appreciated.


texts: What is the proper phraseology for a clearance with a named obstacle departure procedure?

texts:
The Phoenix Mesa-Gateway Airport (KIWA) has a named obstacle departure procedure - the Phoenix Departure.

What's the correct phraseology for when clearance assigns it to you? Is it "N123AB, cleared to XXX, via the Phoenix Obstacle Departure"?


texts:
I'm not sure if this is appropriate to Aviation.SE, so apologies in advance if not.

I have taken several domestic flights over mainland China (as in, the People's Republic thereof) and, so far, it has always been a bumpy ride. I'm more familiar with flying (as a passenger on a commercial airline) around Europe and, to a lesser extent, the US and don't recall it ever being that bad. Likewise, the trip from Europe to China is reasonably stable.

Is there something about the weather or the terrain in that part of the world that causes this? (This, anecdotally, appears to apply both to flights across China, over the mountainous regions, as well as along the relatively flat eastern seaboard.) Or have I just been unlucky?


texts: Is specifically indicating "uncontrolled airfield, student handling radios" by writing "uncontrolled" in a student's log book necessary?

texts:
I'm a student pilot with 52 flight hours.  I've had multiple lessons at the same uncontrolled airfield handling the communications on each leg while doing touch and goes.  The last lesson my instructor wrote "uncontrolled" in my log book.  I spoke with the chief flight instructor she said that it was to indicate that I was flying in an uncontrolled airfield and handling all the radios.  Is it necessary to reflect radio communications for the private pilot exam with the DPE?
As I indicated above all my flight training for touch and goes (except one) has been at one uncontrolled airfield.  After the first lesson on calling postions in the pattern I've handled all radio communications.  Is writing "uncontrolled" necessary for logging progress?

Thank you.


texts: How do fast-flying aircraft avoid overheating?

texts: As a follow-up question to What is the typical temperature of an airliner's hull during flight? I wonder how very fast airplanes, such as the SR-71 mentioned, avoid overheating with a total air temperature outside of more than 400 degrees Celsius.


texts: Why tap the brakes on take-off in fixed gear aircraft?

texts:
The Socata TB10 checklist indicates that you should touch the brakes after lift-off. I assume this is to stop the wheels from turning, but why?

In a retractable gear aircraft this would make sense to avoid using anything in the wheel-well to stop the wheels and potentially causing damage or generate heat (as a side note, I think some airliners actually have brake-pads in the wheel wells for this purpose). However, the TB10 is not equipped with retractable gear.

The TB10 and TB20 are very similar, and it might be a case of copy & paste between the two POHs (the TB10 POH also lists V-speeds for "flaps and landing gear retracted").

Do spinning wheels have an adverse effect on aerodynamics (or handling in general)? I would assume, if anything, they'd produce less drag. And as a cherry on top, I'd also assume they'd start spinning again fairly quickly, as only the lower part of the wheels are protruding out in to the air flow.


texts: How many aircraft types are cabin crew qualified for?

texts: I always wonder, how many types of aircrafts can a cabin crewmember be qualified for? is there a limitation by say IATA, FAA or EASA?


texts: What is this pipe on the tail of this helicopter?

texts: In this picture of a CH-53 you can see a pipe or rail on the tail section of the aircraft. What is that?


texts: What has been the maximum number of failed landing attempts for any commercial flight yet?

texts:
Top DGCA officials say they do not recall any other instance of this kind where a plane tried to land unsuccessfully six times and then finally touched down in the seventh attempt — whether in India or abroad. (Source)

A better written report of the incident.

Coming to the question, what has been the maximum number of failed landing attempts for any fully loaded commercial airliner?


texts: Why are some LNAV/VNAV mins lower than the LPV mins for the same approach?

texts: Why are some LNAV/VNAV minimums lower than the LPV minimums for the same approach? See the RNAV (GPS) Rwy 5 approach at Scott Municipal (KSCX).


texts: What is the purpose of this helicopter fin antenna?

texts:
I'm an airplane guy, but I've got a quick helicopter question. I've seen a few helicopters with what seems to be a fin shaped antenna on the middle of the fuselage just above the windshield. I've also seen them just below the cockpit. And sometimes there's two antennas, one above, and one below.

(source)

Just curious what its purpose is?

The antenne balise de detresse is the one I'm curious about:


texts: What is the relationship between blade inertia and rotor kinetic energy?

texts:
As far as I know:

High blade inertia provides good pilot intervention time (the time
between recognizing engine fail and pushing the collective down).
High kinetic energy allows for a soft touch down after flare in
autorotation.

What is the relationship between blade's inertia and rotor kinetic energy?


texts: During VMC conditions in terminal airspace (class B), does the pilots have to strictly follow separation standards issued by ATC?

texts:
Is it common for pilots to breach separation standards in terminal airspace while the conditions are VMC? I'm interested primarily in commercial aircraft that have scheduled operations in major airports.
I know there are Loss of Separation events reported to FAA - is that a small subset of actual incidents? Are these reports predominantly for during IMC conditions?


texts: What is the naming convention for European airways?

texts: I know that in the U.S. low altitude airways are called Victor (below 18.000ft, e.g. V123) and high altitude routes are called Jet (above 18.000ft,e.g. J123). Can somebody explain the European airspace routes naming? Thanks!


texts: Can you use a home built helicopter for solo hours?

texts: I'm curious to know if anyone has heard of or has any knowledge of using a kit helicopter for the FAA required minimum solo hours of flight training.


texts:
Now, indicated airspeed is pretty much the dynamic pressure that air is creating.
What about true airspeed? How do the calculations go about factoring out all the wind patterns and finding the speed?
Also, for ground speed, how can we factor in the head, tail and crosswinds to determine the ground speed?


texts: What's usually going on in a "hot" military operations area (in the US)?

texts:
Like many people in aviation, I've been around pilots who've flown in or through the edge of a Military Operations Area (MOA) while operating under visual flight rules. Usually they ask ATC if the MOA is hot, and sometimes the answer actually is "yes".  In that case, the pilots stay clear for safety.  My question is, what's usually going on in the MOA at the time and how bad would it be to enter it in VFR?

There are few reputable sources on what typical operations are in military operating areas.  This Global Air blog is the best explanation I could find, although this post isn't a bad source.  Those sources seem to err on the side of exaggerated caution though, describing "lights off" operations, practice dogfights, and 500 KIAS speeds.  Are those kinds of operations daily, or evenly weekly, occurences in military operating areas?  Where on the spectrum from the mundane "practicing approaches" to dangerous "simulated high speed dogfight operating heads-down" do most military flights lie? Are operations consistent or do they vary from place to place and month to month?

Background information for those outside the US:  MOA's are defined in the Aeronautical Information Manual (AIM), paragraph 3-4-5, as well defined airspaces near military bases "for the purpose of separating certain military training activities from IFR traffic."  They are different from restricted zones with particular defensive significance or bomb and missile activity.


texts: As a passenger, can I use my handheld radio in commercial flights?

texts: During flight from one country to another, can I use my hand held radio during flight to listen to ATC?


texts: What open databases with aircraft, airlines and country exist?

texts:
As the above question states, I'm looking for an open database that I can access. I'm building a plane spotter app, and need a lot of data.

The data needs to be downloaded.


texts:
Does the time an ATR 72-600 is running in hotel mode contribute to the flight hour (FH) limit of the DC Generator?
Does running an ATR 72-600 in hotel mode degrade the DC Generator brush differently than running the engine in normal operation?


texts: Is taxiing a small aircraft on a residential street legal?

texts: I live with the back of my house to a Runway that runs north to south almost perfectly.  I live on the west side of the runway, Across the street from me on the further west most side of the road lives my neighbor who owns runway rights,(his house is completely unconnected to the runway) which from my understanding grants him parking privileges at a designated area on the runway itself. does owning runway parking rights make it legal for him to taxi his plane all 200 yards down the residential road in between my house and his to park his plane in his yard?


texts: Is the 737's autopilot part of the FMS or is it a separate entity?

texts:
I was watching a tutorial about the FMS and the autopilot in the 737, and I am consfused. I come from a Cessna background, where there is no FMS, there is only the AP (autopilot).

So, is the AP a separate entity being fed info by the FMS and easily overridden by the values you input into the AP (heading, V/S, altitude)? Or is the AP under the FMS, and the FMS has full authority over the AP?


texts: Why are FDR's called "black boxes" when they are actually orange?

texts:
Why do they call flight data recorders a "black box" if it's orange in color?

Just curious about this since I've seen several images of black boxes but they all come in orange colors, and not black.  I can understand orange being used to help brightly identify the box , but then why call it a "black" box?


texts: Can a jet cruise with asymmetric thrust?

texts: If a twin turbojet aircraft has an engine failure during takeoff, does it return for landing or does it continue to cruise with asymmetric thrust?


texts: Does taxiing time gets considered in a pilot's flying hours?

texts: Basically the title. This could be referenced to US or European rules.


texts: Is there a difference in stability between a tail downforce (cg ahead of ac) and a tail upforce (cg behind)?

texts:
So from what I understand, having a -

1.cg ahead of the neutral point(ac) with a tail downforce

and

2.cg behind ac with a tail upforce

are both stable configurations.(Please correct me if I'm wrong.)

Will the first configuration be more stable due to less lift at the tail?
What are the advantages and disadvantages of both these configuration?

Also if I have a configuration with cg between cp and neutral point, neutral point being the most aft point, will it be stable?


texts: How come certain airports can have unique rotating beacon colors?

texts:
The Hershey Medical Center Heliport has a white-red-green beacon as opposed to a normal heliport white-yellow-green beacon.
How is this allowed?


texts:
I am traveling for a wedding which will take place in Monza Park, Italy. According to Italian Airspace Pro, the location I would like to fly, the southern half of the park, is technically in Class D airspace, which is restricted unless cleared by ATC.

Click image for full view.

I know that in the United States, the FAA regulations state that to fly in restricted airspace, you must:

  Notify the airport and air traffic control tower prior to flying within 5 miles of an airport*

Is flying within restricted airspace possible if I contact a local tower there? Who would I need to contact?


texts: If the map (reading) light bulb is burned out in my own Cessna 210, what are my options if I want to fly FAR Part 91 under night-time VFR?

texts:
If the map (reading) light bulb is burned out in my own Cessna 210,  what are my options if I want to fly FAR Part 91 under night-time VFR staying in the traffic pattern doing touch and goes?

Can I change the light bulb myself (non- A&P mechanic) and go?
Do I have to have an A&P supervise my work if I change the light bulb myself.
What action, if any, do I have to take in order to be in compliance with the FARs.


texts: Why are aircraft tires not pre-spun prior to landing to preserve them?

texts: Why has someone not designed a landing wheel with a fin or fins on it so that the air will start the wheels turning before the wheels touch the ground? Wouldn't that preserve the tires longer from wear? Or would it make the control of the aircraft more dangerous in some circumstances, such as rain or snow, to have the wheels already turning when landing? If so, perhaps the fins could be manually or computer controlled for various weather conditions.


texts: What are the spiral marks in the center of the engines?

texts:
When I get a chance to peek inside an engine, I noticed that many have spiral marks painted in the center. What is the purpose of these?

Pictures:


texts: Why do MP and RPM adjustments have to be made in a specific order in constant-speed props?

texts:
Can anybody explain why do I have to pull back RPM lever first and then pull back MP after climbout when setting up my cruising speed MP/RPM combination. When I make an approach to land I do vice versa - firstly adjust MP (pull back to around 15) and then RPM (set to full).

My training aircraft is Diamond DV20 with automatic mixture control. It has only Throttle and RPM levers.


texts: Which air stream pressure / speed is measured by the pitot?

texts:
The pitot tube is used to measure the air pressure later converted into air speed. However air pressure varies according to several elements, including the location related to the wing:

(Source: av8n.com)

On one hand the probe, depending on its location, could measure the pressure in the free stream, in the high velocity stream, or in the low velocity stream.

On the other hand, pitots are found at various locations, e.g:

On the fuselage, far from the wing, B-737 (source)

On the vertical stabilizer, kit Nemesis NXT (source)

Under the wing, Cessna 172 (source)

Furthermore when the probe is fixed to the fuselage or to the stab, depending on the angle of attack, it can be rotated into the slowed down or the accelerated portion of the stream.

Can you shed some light on what is usually measured by the pitot? Does the pitot indicate different pressures if placed in the different stream areas (free, accelerated, decelerated)? If so:

What is usually measured by the probe?
What is usually displayed on the speed indicator?

Edit: While I needed to select a single answer, several other answers contain additional interesting elements and deserve votes as well.


texts: Are there regulations for the minimum amount of toilets per passenger?

texts:
Are there any rules or guidelines that define the minimum amount of toilets per number of passengers on an aircraft? I know there are similar rules for cabin crew, emergency doors etc.

It seems to be varying per airline the amount of toilets (similar aircraft type)


texts: What are the regulatory categories of aircraft defined by the FAA?

texts: What are the different aircraft regulatory categories aircraft defined by the FAA? Are there any exceptions?


texts: Can a person be operating an aircraft in a "Careless" and "Reckless" manner at the same time? Or are these two different standards?

texts:
U.S. 14 CFR Part 91.13 Careless or reckless operation states:

(a) Aircraft operations for the purpose of air navigation. No person may operate an aircraft in a careless or reckless manner so as to endanger the life or property of another.

Can a person be operating contrary to this regulation in both a "Careless" AND "Reckless" manner during the same operation or are these two separate offenses under single FAR (91.13 [a])?
This is an interesting article that discusses Is “Careless” Different From “Reckless” Under FAR 91.13(a)?
My question is certainly not, in general, a novel one. Maybe there is a knowledgeable person in the ASE community that can shed some light on this question.

After reading the comments and responses below (as of 5/11/2021), I have added some editorial information to my question: (probably far more than you want to read, but interesting nevertheless)
This link from SMU (Southern Methodist University, Dallas, TX), entitled A Legal Analysis of 14 C.F.R. Part 91 See and Avoid Rules to Identify Provisions Focused on Pilot Responsibilities to See and Avoid in the National Airspace System (2015) provides some historical context regarding the evolution of FAR 91.13 (and its predecessor regulations).
It's a long read, but importantly, beginning on page 71 is a background and analysis of 91.13.  Additionally, on page 81 para. 4, entitled "Reckless Standards," is an interesting discussion closely on point with my question (above).
Also, on page 84, para. c., discussing a case regarding a violation of FAR 91.155, "The administrative law judge (ALJ) and the Board  uniformly characterized this..." (the actions of the pilot involved) "...as "intentional, reckless and deliberate behavior and prohibited the application of the Aviation Safety Reporting Program." (emphasis is mine)
It should be noted that in  AC 00-46 (Aviation Safety Reporting Program - filing of a NASA Aviation Safety Report) no civil penalty or certificate suspension is imposed if the criteria for inclusion in the program are satisfied. However, one of the eligibility requirements for receiving the benefits of filing a NASA form is that the "violation was inadvertent and not deliberate." (see para. 12.3.1 in AC 00-46)
So, in the case mentioned in the SMU analysis (above) the ALJ and NTSB found the behavior of the pilot "reckless" and "deliberate" and, apparently on this basis denied benefits otherwise available when filing a NASA form under the Aviation Safety Reporting Program.
With all of the great responses and commentary taken together, there seems to be convincing information that 91.13 specifically provides for, but does not mandate, a distinction to be made between a "careless" operation and a "reckless" operation.


texts: What is the circular pavement at the end of a runway called?

texts:
What is the circular pavement at the end of a runway called where aircraft turn 180 degrees to then backtrack? Is the term runway turning bay appropriate for that?

The problem is that there is a special NOTAM at our aerodrome for big aicraft (more than 75 tons of weight) to turn not on the runway but only in this adjacent part, and with maximum radius due to fragile asphault pavement.


texts:
Peter's answer to this question leads me to another question.

How does the advancing wing in a flat spin create nose thrust?

I imagine this like some object spinning in a liquid.  I would think that the motion of each wing would only create drag that acts as torque opposing the motion of the spin in the geographic plane of the spin that would tend to make the spin slow down rather than be maintained.


texts: Is there a list of directs and preferred routes within USA airspace?

texts:
In Europe it is possible to find a list of directs which are contained in the Appendix 4 of the Route Availability Document from the Eurocontrol website.

My goal is to find the analogous information for the US airspace. I tried to look in the FAA website but without success.
Can you please tell me a way to achieve my goal?


texts: What are these four tubes for in the intake for an Extra 300?

texts:
The fuel-injected engine has six cylinders, so it's not a "per-cylinder" thing nor is it related to a carburetor.

P.S. That screen is the entirety of the air filter. Apparently it's meant to keep out small birds, and not much else.


texts: What effect does the Space Shuttle have on the Shuttle Carrier 747

texts: I saw a picture of this the other day and it got me thinking... How does having the shuttle on the back of the 747 affect the factors of flight? My guess is that is provides an incredible amount of additional drag and obviously weight. What I'm really wondering is do the wings of the shuttle provide some sort of additional lift to the entire aircraft?


texts: What is the work routine of a boomer operator in a refueling aircraft?

texts:
This is a boomer operator:

(source by John E. Lasky - United States Air Force)

If he is not refueling an aircraft, or the plane is not on a refueling mission, what is he doing? Is he sitting in that small cabin all the time, or is he free to move on the aircraft? Can his role be taken by anybody from the crew, or is he the only person on board who can handle the refueling boom?


texts: Could flight MH370 have suffered decompression due to a high altitude bird strike?

texts: MH370 was flying at 11 km altitude at a speed of 872 km/h. It is known that some birds can fly at this altitude, e.g. the Rüppell's vulture. So, could such a bird hitting the windscreen at roughly 900 km/h cause cracks that would lead to decompression? And would such a scenario fit the known facts about MH370?


texts: What activities take place in the warning areas offshore of Washington, D.C.?

texts:
Looking at the Washington sectional, several areas offshore are designated "Warning" areas: W-386, W-107, W-105 etc. The only notes given are "National Defense Operating Areas. Operations hazardous to the flight of aircraft conducted within these areas".

That would be enough to keep me well ashore, but out of morbid curiosity, what kind of activities are we talking about? Are these areas designated for naval gunnery/missile ranges?


texts: What is the direction convention for Roll angle?

texts:
This page from Wikipedia says:

  A positive rolling motion lifts the left wing and lowers the right wing.

Which means that if an aircraft has a roll of +20 degrees, it would bank towards the right. And for a roll of -20 degrees, it would roll to the left.

But when I used this flight indicators library, for a roll of +20 degrees the attitude indicator showed that the aircraft was banking left and vice versa.

Are there any conventions for the roll angle/attitude indicator?


texts: Can someone explain the EASA approval process to fly ETOPS?

texts:
First of all does the TC holder (manufacturer) of a new aircraft have to gain approval to state that the aircraft is capable of flying etops to a certain level..? I.e ETOPS 120.

Secondly does the operator have to then show compliance to show they are maintaining the aircraft for ETOPS operation to gain certification within their AOC?

So can you have an aircraft for example that is ETOPS capable (from manufacture) but not ETOPS certified if airline aren't maintaining to required standard or have approval from NAA?

Basically I don't understand who has to get the approval, TC holder, operator or both from EASA or the local NAA?

It someone can clarify that would be fantastic..


texts: Would there be any benefit in placing the aircraft engines on the elevator (end-tips)?

texts:
Looking at the HondaJet, we can see an interesting placement of the engines.

This leads me to wonder, for a slow flying aircraft how would it be affected with engines placed on the end tips of the elevator? (In other words, at the very edge of the left and right elevator wings.)


texts: Can an orienteering compass be used in place of a protractor?

texts:
First off, please forgive me if this is a stupid question.

I was given a protractor during flight training, learnt to use it and obviously works quite well.

However, I've started using my old maps for sim use and used an orienteering compass which also works quite well

In fact, I found it easier to get bearings using the compass than the protractor.

So for my question, has a protractor always been issued and used, or do some schools prefer to use other orientation tools?


texts: Why is the TPA listed on the Chart Supplement (AF/D) sometimes lower than 1,000 AGL?

texts: I'm looking at B19 in Maine, and it recommends a Traffic Pattern Altitude (TPA) of 995 MSL (800 AGL). Wouldn't 1,000 AGL be safer?


texts: What are the effects of angle of attack on turbines in composed delta wings with jets in upper side?

texts: : a layperson doubt. What would happen during take-off and landing of a machine as Boeing X-48, because of the high angle of attack, the steep attitude of the airplane: would this difficult air supply to turbines?


texts: Is this the first single-engine helicopter clean-sheet design since 1976?

texts:
An upstart in the helicopter business, Marenco Swisshelicopter, claim their SKYe SH09 is:

  “the first single-engine helicopter designed with
  a clean sheet of paper” since 1976.

  If you compare this market with the
  automotive market, it’s like we’re competing with cars from
  1976 whose only upgrades have been airbags and a GPS
  scrolling map. The market has not seen real innovation in
  years.

What 1976-design are they referencing and how accurate is their claim?


texts: Does zero-lift angle of attack depend on Reynolds number?

texts:
In this post I read that, due to viscous effects, the $C_{l}$ at a given angle of attack increases slightly with the Reynolds number but it seems that it just happens near the stall angle of attack.

I am performing some wind tunnel experiments at much lower Reynolds than those of the figure of the linked post (150,000 and 300,000) with the same profile, NACA 4412. My question is if at the mentioned Reynolds, can there be a small variation in the angle at which $C_{l}=0$, and therefore my $C_{l}-\alpha$ curves at Re=150,000 be noticeably below the Re=300,000 ones.


texts: Can the A380 ferry an extra engine, like the 747?

texts:
A useful little quirk about the 747 is that it can ferry a fifth engine on the wing, for when another aircraft is stranded somewhere in the world.

Does the A380 have the same capability? If not, how would an airline manage an aircraft needing a new engine whilst away from a maintenance base?


texts: Can another pilot act as my safety pilot for only part of a flight?

texts:
Let's say I fly with my safety pilot while under IFR plan (I recently earned my IR). I cancel IFR in air since I can maintain VFR for the last, say, 20nm of the journey (assume there was just some weather necessitating the rating earlier on enroute).
In the VFR phase, I don my hood and conduct 1 or 2 practice instrument approaches at or near destination.
First of all, is this ok? Passenger (since right seat sits VFR only pilot) "evolves" into safety pilot?
Second, if legal, how would one log this flight for purposes of currency?


texts: A book I have (Boeing, Planemaker to the World) includes how many orders and planes received of all of Boeing's major models as of the date it was printed. It said the 2707 (Boeing's failed SST) got 125 orders. That seems a lot, compared to the very small amount of concordes and TU-144s that were ever made. What made the 2707 so superior that 125 of them were ordered?


texts: How does the luggage car's driver at the airport know what to do?

texts:
I would like to learn a little bit more about the work of luggage car's drivers.

Specifically -- how do any of them know:

which luggage car to ride next?
which plane must they deliver this particular luggage car to?
which roads must they take in order to avoid dangerous situations (crash with an airplane or other airport support cars)?

If this is not a good place for asking questions like that, is there any procedure or source of information which could help me to answer these questions?


texts: Is there any certification for Aircraft Security that Software Engineers can accomplish?

texts:
I would like to ask you if there is any certification that Software Engineers can take for learning the fundamentals or more exeutive concerning the section of Air Safety and Security. I am talking about Safety protocols like DO-178C or DO-178B or any other.

*It doesn't really matter if it is going to be a US certification or a EU one.

Thank you in advance for your time.


texts: How to make ourselves more visible to other aircraft?

texts: What are the best practices in air to help others see our aircraft?


texts: Are the aircraft used for the A380 display ready to be delivered to airlines?

texts:
For displays in international airshow, Airbus uses A380 whose livery is the one of customers. Here are some examples:

Le Bourget 2011: Korean Air
Farnborough 2012: Malaysian Airline
Le Bourget 2013: British Airways

Are those aircraft regular newly built aircraft ready to be delivered to airlines (with all the seats and passenger equipment inside)? Are those aircraft specially prepared?


texts: Why is the Tu-144 the only commercial airplane with canard configuration?

texts: I understand the delta wing was chosen because of the supersonic cruise (like the Concorde), and canards were added to reduce the approach/landing speed. But canards may be used without delta wing (e.g. Focke Wulf F-19, Soukhoï Su-47, Rutan Voyager,...), so I don't understand why the canard wing configuration is not used among commercial aircraft.


texts: What is the stall speed for the Dassault Rafale?

texts:
Looking at this video of a Rafale escorting a high-speed train (TGV)

I was wondering what the stall speed for the Rafale is at close to sea level altitude.

Is this information generally public for fighter aircraft? I could conceive this would be classified.


texts: Are strategic bombers still useful, or are fighters taking over this role?

texts:
During the mid 20th century and cold war, armies were having clear distinction between those aircraft designed as strategic bombers and those designed to be fighters for aerial combat. My understanding was that there were few exceptions to this rule.

However, the fifth generation of jet fighters include models designed normally for aerial combat but also used for strategic bombing. Old designs of strategic bombers are still being used, but it is clear that jet aircraft are being significantly improved by new developments compared to obsolete bombers.

Why is this happening? Is current warfare no longer requiring strategic bombers? Are designs of jet fighters so flexible that they can perform different missions? (usually it is the other way around, as time passes more specialization is seen).


texts: Why do we never see high-bypass turbofan engines sharing the same nacelle on large airliners and similar aircraft?

texts:
I'm talking about this sort of thing (this is the fictional airplane from Casino Royale), rather than two (or more) engines per wing in individual nacelles:

If we ignore the weird 'drop tanks' on the outer pylons, what makes this design inferior to one with individual nacelles? I can think of some highly speculative pros and cons for both layouts:

Pros for shared nacelles:

Shared nacelle and pylon potentially means less frontal and wetted area per engine, which could maybe reduce overall drag.
Overall, this scheme seems to allow the 'center of thrust' for all the engines on one wing to come closer to the centerline of the aircraft. In some designs like the A380, where a massive vertical fin is needed to maintain yaw authority in an engine(s)-out situation, it seems like this could save quite a bit of weight and drag by reducing the size of the vertical fin.

Cons for shared nacelles:

Obviously there is an increased risk that an uncontained engine failure like the one on an A380 a few years ago could cause cascading failures in its 'neighbor'. I'm not sure how to quantify this risk, but it seems significant.
Additionally, a structural failure in a pylon/nacelle (extremely rare but it does happen IIRC) will affect two engines instead of one.
Maintenance will be probably be more difficult, since you'll have to mess with two engines just to get at one.
I'd expect that due to the structural requirements of supporting two engines on one pylon, you probably wouldn't save much weight and you might actually end up with a heavier aircraft, all other things being equal.
Maybe you'd lose some efficiency in the interaction between the exhausts of both engines in a nacelle?
It might turn out that you can't fit two large high-bypass turbofans into one nacelle without choosing between flow separation issues and greatly increased frontal area.

This is all layman speculation, though. In reality, from an engineer's point of view, is the choice of one layout over the other obvious? Why or why not?


texts: Do professional pilots have to show their passports every single time when flying back & forth between the same airports?

texts: What process do pro pilots have to go through with their passports when on the clock?  Are they afforded any shortcuts or do they have to go through security EVERY SINGLE TIME?


texts: Why does it take so long to develop a passenger aircraft?

texts:
I was researching about the Boeing 737 MAX, and came across some information on a Business Insider page:

  But in the 2010s, Boeing tried to replicate the success of the 737NG with the 737 Max. But this time, it wasn't simply competing with Airbus; it was playing catch-up. Boeing began to discuss a successor for the 737 as early as 2006, looking at both putting new, more efficient engines on an existing 737 airframe, or starting from scratch with a brand new airframe. Boeing knew that Airbus was similarly exploring an A320 replacement, but both companies were still in early stages.It was still trying to decide in 2010, when Airbus launched the A320neo family (neo = new engine option). The jets used the original A319, A320, and A321 airframes, but used new engines that offered a 15-20% increase in fuel efficiency, consequently lowering operating costs and giving the planes longer ranges. Airbus has since released two longer-range variants of the neo family — the A321LR and A321XLR.

Then the article began talking about how it could take up to 10 years for Boeing to create the new aircraft, so instead of creating a completely new airplane, Boeing decided to just add bigger engines.

Now my question is, why does it take so long to develop a new passenger aircraft?


texts: Is reverse thrust needed on a long runway

texts: Every time I have landed on a airplane reverse thrust is needed, but what if the runway is 18,000ft long. Because if the runway is longer couldn't you save fuel by not using the reverse exhaust


texts: Can IPA be used as a FSII with MoGas, particularly with a Peterson STC?

texts:
This question established a basis for the use of 100% Isopropyl Alcohol (IPA) as a Fuel System Icing Inhibitor (FSII) in aviation gasoline systems. However, this Cessna Service Letter documents that IPA is not to be used as a FSII with automotive gasoline in Lycoming powered Cessna aircraft, or indeed in any Lycoming aircraft whatsoever, in accordance with Lycoming Service Instruction No. 1070R.

Now, Peterson offers their auto fuel STC for many aircraft, including Lycoming powered Cessnas, allowing the use of certain types of non-ethenol automotive fuels. Peterson is known for being outspoken about the problems with ethanol as an additive in automotive gasoline.

My question is twofold:

firstly, is there any documented basis for the use of IPA as an FSII with any type of automotive gasoline in certified aircraft fuel systems (I am thinking part 23 certified aircraft, to exclude non-certified aircraft); and,
secondly, is there any documentation for the allowance or prohibition of the use of IPA as an FSII with a Peterson auto fuel STC?


texts: In a turbofan, why are there no stators behind the fan?

texts:
Why are there no stators behind the fan? At least, I've never seen any turbofan design that has stators right behind it. (Here is the latest turbofan I've looked at, the CFM56. Cutaway part starts around 00:35.)

The purpose of stators is to redirect the airflow to be mostly axial. Without them, the air would be spiralling too much.

The fan is the biggest compressor so I would think stators are needed there more than any other place, but apparently that's wrong. I just do not know why it's wrong.

Edit: Yep, there are stators there after all. Just because they're not shown in a video doesn't mean they aren't there. Oh well.


texts: How do I improve navigation with a VFR sectional chart?

texts:
I am doing my PPL atm. I am struggling to navigate with a VFR sectional chart, I am getting lost more often. How do I fix this issue? Any tips?

I have trouble identifying small towns, identifying places if there are no big landmarks.
How do I identify places more accurately?


texts: What was the first aircraft that could fly inverted?

texts:
I'm taking a guess and assuming the Wright Flyer was incapable of flying upside down.  I'm just guessing it probably lacked the power... ;)

So what was the first plane that could fly inverted for a sustained period of time (10sec+) with full power?  I'm assuming you would need an engine that was okay being upside down*, and had the power to get you high enough to make the maneuver safe.  Then you'd need an airfoil that worked inverted (some of the high early cambered wings may have had problems, for example) and controls that functioned in that environment as well.  Probably a seat belt would be useful too.

Anybody know what plane was the first one to have all of these, and then went ahead and flew upside down?

Bonus points: I also wouldn't mind knowing what plane was the first to simply fly inverted, even if for a brief moment...

*As Jan Hudec pointed out, the engine itself doesn't really care, but the fuel system might.  So really we should be asking when the first fuel system that could go upside down was produced...


texts: What type of aircraft would fly with an orange light at night?

texts: I know planes usually fly with red lights which seem small in the sky, but last night i saw a bright orange blinking light traveling through the sky; it was bigger then a star but was orange. I thought it might be a helicopter, although I read it could have been a comet or a meteor.


texts: When to climb and when to descend when faced with icing?

texts:
(YouTube)

The flight faced icing at FL 90 inbound to Germany from the UK on a world tour. Earlier they were flying above an overcast layer.

After they saw the icing they requested FL 70, and asked what's the minimum altitude, which was 5000 feet. How do GA pilots decide that descending is better than climbing, as in climbing away from the moisture layer?

The plane is a Cessna T210L Turbo Centurion that should be capable of 27,000 feet.


texts: How do Flight Test Engineers plan and execute sortie profiles?

texts: Can someone from the field explain with a simple example the process of planning and executing a sortie profile as an FTE. Any reference books for an insight into the subject would be appreciated.


texts: Has fuel boiling ever been an issue for high altitude aircraft?

texts:
Are special measures being taken to prevent fuel from boiling inside the fuel systems at high altitudes? If so, when (with what aircraft) did this practice start?
(question is pertaining to air-breathing, hydrocarbon fueled engine powered aircraft)


texts: If unexpectedly in IMC, does it help to climb into clouds to get on radar?

texts:
I gather that in the flatlands, probably not. But here is a tragic accident where a VFR-only pilot attempted to navigate steep mountain passes in Utah (Evanston, Wyoming west to Coalville, Utah, and south on to Heber City).  The clouds were reported to be closing in, but he wanted to go see for himself, and  promised ATC he would quit and go back "if" (when) visibility got too bad.  He was too successful following the freeways, and got cocky. Made his turnaround decision too late, turned around successfully, and headed back out the way he came - but collided with terrain nonetheless.  Reports compared with maps make it sound like he got turned around alright using the sky over a reservoir, and my guess is he lost contact with his "concrete compass".  It was terrible judgment all around.  Shouldn't have been there.

He did have a squawk, and was periodically picked up on radar.  He was too low for radio without relays.

Would it have been a viable strategy, instead of staying low in known mountains hoping for a sliver of navigable air between clouds and rocks... to boldly climb into the clouds, get seen by ATC, get enough altitude for radio, apologize and ask to be vectored back to usable VFR territory?


texts: Is there any benefit to science from the Swiss built solar plane flying across the globe?

texts: Are there any innovations that were made during the development or flight of the Solar Impulse plane that would go into any type of regularly used airplanes in the near future?


texts:
Some airports (mostly busy Class B airports from what I gather) have a landing fee. For example, in the Airport Facility Directory for San Francisco, there is a section under "AIRPORT REMARKS" that says "Ldg fee." In a Summary of Airport Charges for San Francisco airport, this fee is listed as at least $190 for Fixed-wing GA aircraft! There is no mention in this document about how the fee is collected, however.

How is this fee collected?