texts: What safety issues led the FAA to ban Constellation flights into/out of the U.S.?

texts:
Although the Lockheed Constellation (like the other late, large piston airliners) was superseded in the 1960s and 1970s by newer jets (plus turboprops for shorter/lighter routes), it hung on into the 1990s with various Latin American airlines, who used them for international flights to and from the U.S.; this only ended in 1993, when the FAA abruptly banned the last of these airlines (all of them from the Dominican Republic, weirdly enough) from flying their Constellations in U.S. airspace.  According to Wikipedia, this ban was due to some sort of safety concerns:

  Most Super Constellations were retired by their original operators after the advent of the Boeing 707 and Douglas DC-8 jet airliners. The last commercial flight of the L-1049 Super Constellation was in 1993, when the Federal Aviation Administration banned all airlines from the Dominican Republic that flew Constellations to the United States (due to safety concerns). The Dominican airlines were the last operators of any version of the Constellation.

I’m at a loss as to what those safety issues could be:

Was it due to concern about poor safety practices at those airlines, rather than concern about poor safety of the Constellation per se (but, then, why weren’t there at least one or two Constellation-flying carriers that did meet the FAA’s safety standards)?
The Constellation being an old, pressurised aircraft, were they worried about metal fatigue (but, then, why did the FAA impose a total flight ban on the Constellation, when fatigue-life concerns haven’t caused them to impose such a penalty on any other aircraft - especially since fatigue would be less of a concern with piston airliners like the Constellation than with jetliners, due to their lower cruising altitudes and resultant lower cabin pressure differentials)?
Were the old, large, temperamental multi-bank radials used by large piston airliners such as the Constellation simply incapable of meeting increasingly-strict engine-reliability requirements?
Was the FAA casting a jaundiced eye on the safety hazards of U.S. airports having to store vast quantities of the extremely-high-lead grades of avgas needed by the aforementioned engines?
Something else?


texts:
Every satellite picture I've ever seen of carriers in port usually shows a lot of equipment on the flight deck, presumably involved with servicing and overhauling the ship between cruises.  This example is from NAS North Island in San Diego.

A closer inspection of the stern of the ship shows what appears to be a derelict F-18 airframe parked on the flight deck and stripped of its engines, LE and TE flaps.

Usually the airwing is launched back to naval air stations on shore prior to the ship reaching port, then fly out again to trap aboard when the ship goes out to sea again and this jet doesn't exactly look flight ready.  What exactly is this aircraft used for?  Is it some kind of training device for shipmates or aircraft handlers or for training on firefighting techniques?


texts: Can an airliner complete a flight with one pack inoperative?

texts:
I was travelling as a passenger on a 747-8. Around 5 minutes after we left the gate, the captain said we had to return to the gate due to "technical issues with the air-conditioning". The mechanic troubleshot the problem for around 45 minutes, during which the air-conditioning was completely off (but the fans were still running), and it was getting hotter by every minute. Finally, the announcement came and told us the problem could not be repaired on spot. We had to switch plane to continue the journey.

Most airliners have two "packs": left and right. They provide air pressurization and temperature control to the cabin.

Is it feasible to complete an entire flight with one pack inoperative?
If #1 is true, is it legal to takeoff with one pack known to be inoperative? (i.e. does the Minimum Equipment List allow this?)
If one pack fails shortly after takeoff, would the pilot turn around and land, or continue to the destination?
What alert message did the pilots likely got in their cockpit in my case?


texts: Should I mention an altitude restriction from the previous controller during an ATC handoff?

texts:
I was flying my first solo cross country today with VFR flight following heading east at 5,500 ft. As I approach my top of descent (TOD), the controller nonchalantly said, "[call sign], you can descend to 4,500, if you want." So I replied that I would descend to 4,500. I got handed off to the next controller and told him, "[call sign] level at 4,500." He got somewhat annoyed that I wasn't at an odd-thousand-plus-500 foot altitude heading east, so I told him I would continue descending to 3,500.

My question is, how should I have handled this? Should I have told the new controller I was restricted at or above 4,500 even though the previous controller didn't explicitly say I was restricted (recall she just said, "you can descend to 4500, if you want").


texts: Why are several of the Tu-104’s cabin windows oddly positioned?

texts:
The Tu-104 (the fourth jetliner to fly1 and the second to enter revenue service2) has a cabin-window layout that is... somewhat odd, to say the least.

From front to back:

What appears to be the second cabin window from the front (although, given how far forward it, and the window in front of it, are, I’m not sure that they are actually cabin windows; I’m not familiar with the location of the Tu-104’s cockpit bulkhead) is mounted so high on the side of the fuselage (the whole window is in the white region above the blue livery striping on the sides; in contrast, most of the Tu-104’s cabin windows are mounted near the middle of this blue band) that one would only ever be able to see the sky through it, unless something was going really wrong.  It and the one in front of it also appear to be slightly smaller than the windows further back, but this could just be perspective or a trick of the eye.
The two consecutive windows over the front middle section of the wing are mounted higher than the windows in front of and behind them, although not as high as the window discussed in point #1 (most of the area of these windows still falls within the blue area, with only the tops of the windows breaching the white).  The more forward of these two windows appears to form part of the second overwing escape hatch - but the window in front of it looks to be part of the forwardmost overwing exit, and, yet, is mounted at the normal height - and these two windows have Aeroflot’s winged hammer and sickle painted in the space underneath them - but I’m having a hard time believing that a simple livery detail would have any significant influence on the design of the aircraft itself (it’s usually the other way around!).
The fourth window from the rear is mounted about as high as the windows discussed in point #2.  It lies above the numeric portion of the aircraft’s tail number, but - again like with point #2 - I’m having great difficulty believing that the window placement was simpler to alter than the paint job.
Finally, the three rearmost cabin (I think?) windows are mounted very high on the fuselage - about as high as the window in point #1.  These three windows overlie the “CCCP” portion of the aircraft’s tail number (but, again, see points #2 and #3!).

Why the wonky window work?

1: ...preceded by the Comet, Jetliner, and Caravelle.

2: ...preceded only by the Comet.


texts: I'm looking at different VORs on a sectional chart and I see the frequencies but I also see a channel number associated with them as well. What are these channel numbers and how do you use them?


texts: What is "picture flying" and does the FAA define it?

texts:
What is "picture flying" and does the FAA define it in any of their literature?

Here is an example situation. You are instructed to depart using a SID. The SID states that at 1.5NM from ABC VORTAC a left turn should be made to heading 360. Your FMS allows you to draw a 1.5NM ring around the fix on your moving map, so you draw the line. When the little airplane is at the line, you make the turn. Anecdotally, I have been told this constitutes "picture flying" and isn't a legal way to comply with instructions from a SID or other procedure. The legal method would be to tune the VORTAC and make the turn when the DME reads 1.5NM.

One could make the argument that the DME is as inaccurate as the visual estimate from the picture flying. Aircraft climb at different rates and the angular distance affects the straight-line distance across the ground, especially if the instructions are something like, cross 20NM from ABC VORTAC at 10,000 feet.

Any definition or clarification from FAA publications or letters would be appreciated.


texts: Why does FAA not include certain SIDs and STARs in its CIFP file, even though they are regularly used in flight planning?

texts:
I was correlating the instrument flight procedures found in flight plans from 1st April 2019 with the ones included in FAA's CIFP database. I noticed that in those flight plans there are some SIDs and STARs which are not coded in the CIFP file. Is that possible? If yes, is there any reason why these flight procedures are omitted?

Examples (SIDs):

JITKA2: KSGU.JITKA2.JITKA. (...)
MCOY2: KMCO.MCOY2.GUANO.. (...)


texts: Why do jet engines get better fuel efficiency at high altitudes?

texts: I'm told that this is true, but I can't imagine why.  It seems like the fact that there is less air would make the engines less efficient...  But that probably just shows how little I know about jet engines.


texts:
In flight simulator, using the NAV setting directs the Autopilot to follow the FMS' pre-setup flight plan and will navigate the aircraft through each of the configured waypoints.

In real life, however, it seems almost a guarantee that ATC will provide some heading which is not necessarily the most direct route, ie. what your flight plan had configured. ATC will request you turn right or left somewhere around the waypoint you expected, but not where you or the NAV system would have turned.

Even in the simulator, if you use the built-in ATC, it will give headings that are not what the flight plan had expected... making the NAV button not very useful except when flying VFR without following.

It seems the autopilot HDG feature is used more often. Is this true in real life as well?


texts: Do IFR flight plans ever get rejected for operational reasons?

texts:
I'm not talking about errors or omissions. Does a FP ever get rejected for example if there are too many flights scheduled into an airport or it conflicts with other flights or your FP as filed would take you through an active TFR area? How much scrutiny does a FP get when it's filed?

From this question I see that VFR plans get pretty much just filed away in case you need S&R. Does someone at ATC go through and verify that an IFR plan doesn't have conflicts?


texts: Why don't single propeller planes rotate around the horizontal axis?

texts:
According to Newton 3rd law, every action has reaction force  in the opposite direction. That's how spaceship can move in space. That's why helicopter needs a second propeller in the back to prevent it from spinning in the opposite direction of the main propeller.
But why single propeller planes do not rotate around its horizontal axis opposing the rotation of its propeller ?


texts: Why in helicopter autorotation phase the opposing torque is eliminated?

texts: As you many know, according to Newton's 3rd law for every action there is an equal and opposite reaction, as the main rotor of a helicopter turns in one direction, the fuselage tends to rotate in opposite direction but when there is no engine power during autorotation, there is no torque reaction, why???


texts: What are the expected vibration frequencies in a co-axial rotor system with contra-rotating propellers?

texts:
I am trying to understand the frequency spectrum of a co-axial rotor system. Form now i have a RC helicopter with two sets of three gear systems arranged in parallel, The number of teeth are 7,23,27) respectively. The 2 input dc motors are running at 35K RPM which runs the rotors at approximately 2800 RPM because of the total gear ratio 12.47.
What I understand the frequency spectrum should have
-6 peaks of individual gears at there respective rpm's.
-2 peaks of Gear Mesh Frequency
-2 peaks of blade pass frequencies (rotor have 2 blades each total 4 blades in the RC helicopter.
Is there anything I am missing in this?


texts: How should I interpret this TAF involving TEMPO and BECMG blocks?

texts:
with the reference in the TAF below , I was looking for the VIS at 0500 UTC and I was little bit confused because  of the " TEMPO "

And the TAF was

LHBP TAF (FT)140400Z 141206 34006KT 9999 BKNO45
TEMPO 1215 VRB10G2OKT 7000 SHRA SCT033CB BKNO40
FM1700 CAVOK
BECMG 2022 VRBO1KT 5000 BR NSC
BECMG 2201 1200 BCFG BR SCT002
BECMG 0104 0600 FG OVC001
TEMPO 0406 0150 FG VV001

According to the TAF at 0104Z VIS would be 600M, then we can see TEMPO at 0406 with 150 M VIS, so what VIS can we expect?  Can we say it is 600M with possibility to be 150 M? Or we can say directly it is 150M?


texts: What do professional pilots keep track of in their pilot log books?

texts:
Professional pilot logbooks (either paper or electronic) always seem to be more elaborate than those used by private pilots.

I am curious as to what a professional pilot finds important to track in their logbooks besides just total flight time in aircraft type.


texts: What are RW values in Venule increments?

texts:
In US AIP differences from ICAO:

12.3.1.7 d/e/f
U.S. controllers do not give wind speed, visibility, or RVR values in metric terms. RVR values are given in 100- or 200-foot increments while RW values are given in Venule increments. [emphasis mine]

Same AIP's abbreviation list does not mention RW. Google wasn't helpful.
Here 12.3.1.7 d/e/f references chapter 12 of Doc 4444 15th edition (not the latest). The same section in the latest 16th edition is irrelevant (phraseologies regarding traffic information). If I find the older 15th edition I'll update.
The same entry is present in the Nov 2016 AIP edition, so it's neither new, nor a likely typo (PDF; 20 MB).


texts: What is the most simple plane lift equation that gives realistic solutions?

texts:
I need the most simple lift equation that once solved with Mathcad gives a realistic vertical speed of a plane and implicitly the altitude h(t).

Also the drag eq. (1) leads to a good solution, a Vh(t) that increases and finally reaches a limit (the maximum horizontal speed) and stays there during the duration of the flight, the lift eq. (2) stabilizes at a Lift(t) - m * g = ct. > 0 and in consequence Vh(t) keeps growing indefinitely because an eq. of the type m * dVv(t)/dt = ct. leads to a solution Vv(t) that rises linearly with time.

Question:
It is quite clear that the vertical speed of a plane, Vh(t), can not grow indefinitely. How can I stabilize it to o constant value. What do I have to add in the lift eq.?

Drag eq.: m * dVh(t)/dt = T - Drag(t) (1),

Drag(t) = 0.5 * Cd * r * S * ( Vh(t) + Vw(t) )^2,

Lift eq.: m * dVv(t)/dt = Lift(t) - m * g (2),

Lift(t) = 0.5 * Cl * r * S * ( Vh(t) + Vw(t) )^2,

where:

Vh(t) = horizontal speed, Vv(t) = vertical speed, both of them have to be determined being unknown functions.
known parameters: m = the mass of the plane, r =  air density, S = the wing surface, T = thrust = ct., Cd, Cl are the drag and lift coefficients, g = 9.81 m/s^2, Vw(t) = the wind speed, that is usually a known constant but can have other forms given as functions of time, t.


texts: What are the flow properties for the engines of a Fokker 70 with reversers deployed?

texts:
I want to know what the approximate flow properties would be at the exit of the nozzle for a Fokker 70 with reversers deployed. What is the exit velocity of gas at the nozzle?

How do they calculate values of reverse thrust? Can anyone explain what the range of thrust settings is when using bucket reversers?


texts: Why are there extra restrictions on constant-speed propellers?

texts:
Constant-speed propellers are far more efficient than non-constant-speed propellers, allow the engine to be made considerably simpler (due to removing the need to continuously adjust the ignition timing based on how fast the shaft is rotating at any given moment), and, unlike traditional variable-pitch propellers, don't require the pilot to manually adjust the propeller pitch.

However, according to Wikipedia, propellers with constant-speed mechanisms have considerably tighter restrictions on them than other propellers:

  A pilot requires some additional training and, in most jurisdictions, a formal signoff before being allowed to fly aircraft fitted with a CSU [constant speed unit; the part of the propeller mechanism that makes it a constant-speed propeller]. CSUs are not allowed to be fitted to aircraft certified under light-sport aircraft regulations in the United States.

Given that a constant-speed propeller performs its pitch adjustments automatically, without the need for pilot intervention, and that constant-speed propellers perform better, not worse, than other propellers, why all these extra requirements and restrictions?


texts: How do you reconcile an airline flight number with an ADS-B record, is this possible?

texts:
If you go look at arriving flights at an airport, you'll see something like "American Airlines Flight 224."

How do you cross reference that ADS-B flight data?  Is this possible?  Seems like there's some information in the "Call" field but it's not enough to match up the flights.


texts: What is the correct term for the type of performance chart where curved lines are followed?

texts:
What is the correct term for the type of performance chart where, from a starting location, curved lines are followed to various reference points to eventually find a solution?
For a specific example, the type of chart I'm asking about can be found in the Pilot's Handbook of Aeronautical Knowledge as Figure 11-23:

Background to the question: I would like to reverse-engineer a performance chart in order to use it in a spreadsheet. I have no idea how to do this but if I can discover the name of the type of chart it is, I can begin by looking for notes from other people who have attempted the same.


texts: Does the pressure change inside a plane when it is opened for paratroopers?


texts: I am wondering if any plane can become ETOPS certified? And, is ETOPS the right acronym?


texts: Why don’t most aircraft have emergency braking parachutes?

texts:
Braking parachutes were standard on first-generation jetliners, but have since fallen almost entirely out of use except on military aircraft; essentially the only civilian aircraft nowadays to still carry braking parachutes are some Learjets, which have emergency parachutes to help prevent an overrun during a landing or high-speed rejected takeoff if the runway is slippery or if one of the aircraft’s primary braking systems (reversers, spoilers, wheelbrakes) malfunctions.

Given the relatively frequent occurrence of runway overruns (often resulting from slippery runways or from takeoffs rejected near or after V-1), why aren’t most civilian aircraft (especially large, heavy ones, which need lots of runway to slow down even under ideal circumstances, and need all the help they can get if circumstances are less than ideal) equipped with emergency braking parachutes to help prevent overruns?


texts: Are there any true aerobatic helicopters that aren’t built around the Bo-105?

texts: I know that some aerobatic maneuvers have been performed (legally or otherwise) in many different models of helicopters. However, to my knowledge, I have only heard of Bo-105s being specifically modified for this purpose, supposedly due to their hingeless rotor system. Are there any other aerobatic models flying at air shows in other parts of the world?


texts: Why does the stall angle decrease as camber increases?

texts:
I have a rough idea about why $C_{{l}_{max}}$ increases with increase in camber.
But I can't explain why the stall angle decreases simultaneously.


texts: Why is there no lift component when calculating rate of climb?

texts:
I read this post about how to calculate the rate of climb
How does climb-rate vary with density/pressure altitude?
So in the image, all the forces are drawn. I am wondering, why the rate of climb does not depend on the lift force (or not directly (?) ).
So the forces acting in the vertical direction are: a small drag component, a big lift component, a weight component and a thrust component.
A steady climb would mean, that all forces are in balance - so no acceleration in any direction. But on the other hand in on post it is said "Calculate how much power is needed to overcome drag, and any excess can be used for climbing" - so when there is more force available in one direction - there should be an acceleration in this direction?
I am a bit confused ... is the rate of climb = velocity in the body fixed airframe (so where the airplane is flying to) ? Or is this the vertical velocity in z-direction?
Thank you for your support says
Helmut


texts: What to do if the captain smells like alcohol?

texts:
Suppose you're the co-pilot on a flight and during pre-flight, talking to the captain, you smell alcohol.

Although you didn't see him drinking and the smell isn't strong, what does regulation stipulate you should do?


texts: Why are airplanes sometimes led by a vehicle?

texts: Airplanes are sometimes led by a vehicle on taxiways until they reach the runway or stand, why is this?


texts: How is fuel planning done for a VFR flight that involves multiple full stops?

texts:
Doing first cross country flight plan with several stops along the way.  What is the general rule of thumb for calculating time, fuel, etc. for a mid trip landing?  I've done conceptual flight plans with checkpoints etc, but not actual stops.

In other words, I can calculate fuel burn, ground speed, course etc. for a point to point flight.  Just not sure what to calculate in by adding a full stop in the middle of that same flight.

While studying for the FAA knowledge exam it sometimes said calculate 3 minutes for take off and departure but curious if there is a generally accepted set of numbers.


texts: Is there any plane that has wing of both aerodynamic and geometric twist?

texts: For the proper lift distribution, afaik either of the twist are used? Is there any significant difference having one over another and both? Thank you. The above question has one line answer and both questions can be merged into one.


texts: How many hours to remove and install a Cherokee 180 engine and prop

texts:
How many hours should it take a shop to remove, install, and adjust the engine in a Cherokee 180 with a fixed pitch prop?

This would include the baffles and any hardware needed to be removed and installed for an engine swap.


texts: The landing gear should be down in order to qualify as a stabilized approach. Other than that, what are the guidelines on when to deploy landing gear on approach?


texts: Why do parked planes lock the control surfaces?

texts:
After a discussion in chat about control surface locks I was wondering why they need to be locked in the first place.

Why do they need to be locked?

What is the best position to lock them in? up, down, neutral.


texts: Would fitting a T-tail on the 737 Max make MCAS unnecessary?

texts:
This is pretty far out, so I just pose it as a question for notion or ideas, rather than conclusive answers.
Considering the differences in flight characteristics between the Boeing 737 Max-8 and older models demanding the creation of MCAS and subsequent problems and crashes;

would it be possible to bring the characteristics back into the existing 737 envelope by lifting the horizontal stabilizers to the top of the tail, rendering MCAS obsolete?

Would certification heritage from the 727 allow for such a change without demand for recertification?

If so, to what extent?


texts: How does vorticity change the lift coefficient of an airfoil?

texts:
For airfoils in unsteady motion, the lift coefficient oscillates and the wake is characterized by vortex shedding.
How does vortex shedding affect the lift coefficient for an airfoil?


texts: Why do early airliners have "backward slope" windows

texts:
Does anyone know why many 1930's airliners in the US have cockpit windows that slope down and rearward, the opposite of what you might expect?

Consider the Boeing 247:

https://www.flickr.com/photos/sdasmarchives/9085364593

Or the Lockheed Electra Model 10:

https://en.wikipedia.org/wiki/Lockheed_Model_10_Electra#/media/File:Kelly-Johnson_Electra.jpg

Or the Ford Trimotor:

https://wjon.com/around-the-town-taking-a-ride-on-a-1929-ford-tri-motor-video/

This seems to have disappeared shortly after, the DC-2 and on, for instance, lack this feature.


texts: Are there any pressurized piston-engine aircraft?

texts: Are there any pressurized piston engine-powered aircraft? Or does pressurization require a turboprop or jet?


texts:
A few hours ago, a rather large (243 feet long) helium blimp owned by NORAD broke loose of its moorings in the Eastern United States and floated away. The news is currently reporting that it's being "escorted" by a pair of F-16's as it floats along at 15,000 feet, and is currently somewhere over Pennsylvania. (Next state over from where it started, at the Aberdeen Proving Grounds in Maryland.)

Given this situation, what are the military's options for recovering this blimp? Do they have to wait for it to crash land somewhere eventually (when it runs out of wind, I suppose?) Or is there some other option for them to "catch" this blimp given its size and the fact it's pretty much under nobody's control?

Here is an article about it: "JLENS blimp has come free of its tether at APG, now floating over Pennsylvania; fighter jets monitoring." The Baltimore Sun. 28 October 2015, 14:34 ET.

Edit: In case anyone is curious, the blimp landed in Pennsylvania a few hours after I posted this question.

Miklaszewski, J. "National Guard to Shoot at Crashed Blimp to Help It Deflate." NBCNews.com. 29 October 2015, 14:32 ET.


texts: Why doesn't the Convair 580 have check valves to prevent inadvertent fuel transfer?

texts:
The Convair 580's fuel system is composed of two wing-mounted fuel tanks (one in each wing), each with its own shutoff valve (which can be closed to isolate its respective tank from the rest of the fuel system and prevent fuel from entering or leaving the tank) and boost pump (which forces the fuel, under pressure, to the respective engine(s)), plus a pair of crossfeed valves (one on each side of the aircraft) to allow an engine to be fed from its contralateral fuel tank if necessary.

Normally, the crossfeed valves are kept closed, and each engine is fed from its ipsilateral fuel tank.  However, if crossfeeding does become necessary (for instance, if one fuel tank drains due to a leak [in which case both engines must be fed from the non-leaking tank] or if one engine fails [in which case the remaining engine must be periodically switched between the left and right tanks to prevent the weight of the fuel in the tank ipsilateral to the failed engine from unbalancing the aircraft and causing a loss of control]), the crossfeed valves are opened, and the tank shutoff valve for the tank not being used must be shut off; otherwise, the boost pump for the tank being used can end up pumping fuel into the tank not being used rather than to the engines.1

Transferring fuel from one tank to the other is expressly prohibited for the Convair 580, as doing so could lead to, in increasing order of severity:

Fuel being lost through the overflow vents in the recipient tank (which is bad because it wastes fuel);
The aircraft's entire fuel supply being pumped into the tank not being used (which is bad because it can result in both engines flaming out despite the aircraft's fuel system containing plenty of fuel);
The recipient tank (and its associated wing) bursting (which is bad for reasons that should be immediately obvious).

However, there is no mechanism to prevent fuel from transferring between tanks if the pilot forgets to close the shutoff valve for the tank not being used, which leads to the Convair 580 being an aircraft where fuel transfer is, simultaneously,

Prohibited under any and all circumstances, as doing so could cause a fuel tank to overflow and/or burst; and
Quite easy to make happen, simply by opening the crossfeed valves and forgetting to close the shutoff valve for the tank not being used.

This seems almost trivially easy to solve, by placing one-way check valves in the lines leading from the fuel tanks so that fuel is physically prevented from transferring from one tank to the other, but, according to the NTSB (footnote 46, page 25/35):

  One-way check valves are not typically installed on airplanes, and the accident airplane did not have one installed. According to a Kelowna Flightcraft representative, one Convair 580 operator modified its fleet of about 30 Convair 580 airplanes in the 1960s under an engineering order by installing a one-way check valve, which prevented fuel from flowing back into the fuel tanks when the fuel tank shutoff valve was left open. However, the representative stated that this operator was no longer in business and that its airplanes had represented a small percentage of the entire Convair 580 fleet.

I can see no reason not to use one-way check valves in the Convair 580's fuel system, given the potentially-lethal consequences of transferring fuel between tanks and the frightening ease of inadvertently doing so.  So why doesn't it use them?

1: The boost pump for the tank not being used must be shut off to keep fuel from being pumped from that tank, rendering it incapable of preventing fuel from transferring into the tank not being used.2  Even if the pilot forgets to turn it off, fuel can still be forced through the pump in the reverse direction if it (the pump) happens to be less powerful than the boost pump for the tank being used.

2: And, if the pilot closed the shutoff valve without turning off the associated boost pump, the force of the pump pumping against the closed valve could potentially cause a fuel line to burst.


texts: Are there surveillance cameras in aircraft cargo bays?

texts:
I've heard that there are cameras on the fuselage and wings of some passenger aircraft. Is there a similar surveillance system in-built at the cargo bay/compartment of a passenger aircraft?

During the baggage loading / unloading of passenger aircraft, many burglary events can be experienced. I think that if there was a camera surveillance system, theft could be reduced significantly. At the same time, when the fire warning was received from the compartment, the pilot could confirm by monitoring the cargo compartment whether the warning was correct and avoid unnecessarily diverting. In addition, the perpetrators of compartment damage occurring in cargo loading / offloading could also be easily identified.

Why did the aircraft manufacturers not consider installing in-built cameras in the cargo compartment?


texts: Do commercial aircraft have electrical outlets?

texts:
As we see trains nowadays with sockets for you to plug your laptop into, as well as Wi-Fi on-board both trains and planes, I'm wondering why you don't see electrical outlets on planes?

Do any airlines have sockets in the cabin? How about in first class?


texts: How can one determine if a Service Bulletin is still applicable?

texts:
I've seen the occasional Service Bulletin that is marked Obsolete, and others that Supersede SB-123. If I'm a pilot or A&P looking through logbooks, what resources are available to determine if a given SB still applies to the aircraft?

For example, American SB-131 applies to AA-1, AA-1A, and AA-5 aircraft. However, this scan (pdf) seems to suggest that it's obsolete, and the contents are now in the service manual.


texts: How can one fly a stabilized approach when the final approach path is curved?

texts: Some approaches, like the KMTN VOR/DME RWY15 depicted below, have a final approach segment that is curved (in the case below, the entire leg from FAF to RWY is one big DME arc, but this could also happen in RNAV approaches using Radius-to-Fix instead).  However, it is said that one cannot be in a turn in order for an approach to be considered "stabilized" (this is most often stated in the context of circling approaches, but is still applicable for straight-ins of course).  What does one do when stuck with an approach that cannot be flown within stabilized approach criteria?


texts: How much do '1,500 total hours with 500 multi crew hours' cost in Europe?

texts:
This company offer a 'fast-track' modular course which, in their words:

  Our speciality is the training of pilots with no flying experience to become Fastrack airline ready pilots by means of continuous Modular training. If this course is commenced on a full time basis it is possible to complete in under 12 months however the majority of students will take between 12 – 18 months to graduate. This will provide the cadet with a ‘frozen’ European Aviation and Safety Agency (EASA) Airline Transport Pilot Licence (fATPL). The Licence will remain ‘frozen’ until 1,500hrs of Total time and 500hrs of Multi Crew time have been achieved.

They also add:

  100% of Aeros Fastrack graduates have been placed with major airlines across Europe over the past two years.

All for the relatively low cost of around 62,000 Euros.

My question is about the last part of that, regarding hours. How much time (months/years) and how much money would it cost to achieve the 1,500 total hours with 500 multi crew hours after completion of the fast-track?

Several aviation forums suggest this is a much better deal than the airline provided schemes, where they normally charge around double this in order to actual turn a profit on training.


texts: What are the requirements to take the private pilot check ride?

texts: In the US, what are the requirements that a student pilot must demonstrate to their examiner  before they can take a checkride for their private pilot airplane certificate?


texts: Did commercial airliners have microwave ovens in the past?

texts:
So I went on 2 long (total of 16 hours) flights with a major US airline, and they did not provide a free in-flight lunch (grr) during either flight. I had brought a sandwich with me just in case, but when I asked the flight attendant if they could heat it up they said that they did not have microwaves. This was I think a 757 or similar aircraft.

When I landed I was asked about my trip, the microwave thing came up and was told (by an older person) that airlines did have microwaves and that mothers with children would often ask the flight attendants to warm up bottles of milk for them...?!

So now I'm curious, did aircraft used to have microwaves in the past? Were they removed? I now know the food they serve on airplanes is "heated via hot air ovens" but why would there not be a microwave on board? Even if just for crew use?


texts:
On this wiki page (under 'Comparison with heavier-than-air aircraft'), the altitude record of the L-55 Airship states:

  The ultimate altitude record for a rigid airship was set in 1917 by the L-55 under the command of Hans-Kurt Flemming when he forced the airship to 7,300 m (24,000 ft) attempting to cross France after the "Silent Raid" on London. The L-55 lost lift during the descent to lower altitudes over Germany and crashed due to loss of lift.

I understand that lift on an airship is created through internal heated air and/or gases, rather than by the movement of air over a wing.

So, how exactly can an airship lose lift? (And how does altitude affect this?)


texts: What United States state and federal agencies generally participate in aerial weather modification?

texts: Also wondering which agencies regulate weather modification activities? Any idea where I can find more information about this?


texts: How to determine the MAP for an RNAV MDA approach?

texts: On this RNAV approach plate, what is the missed approach point for the LNAV MDA approach? How do you arrive at this answer?


texts:
In the answers to this question about wing thickness, there were many references to wing thickness as a percentage (ranging from 6.5% to 13.5%).

What is that a percentage of?


texts: Precision Approach systems: Why is ILS used more frequently than PAR and MLS?

texts:
I have studied that the main three systems for performing Precision Approaches (PA) are the ILS (Instrumental Landing System), PAR (Precision Approach Radar) and MLS (Microwave Landing System).

However, in most of the airports the ILS is implemented as the main PA aid; while the others are often developed, but not fully implemented or unused.

Questions:

What's the reason that the ILS is the most popular PA system?

What are the benefits and disadvantages of the other systems for not being as much considered?

How do they compare regarding approach performances?


texts:
I would like to know the whole process to become a flight test engineer (FTE).

Do I need to take any FAA specific flight test engineer certificate, apart from an aerospace engineering degree? Do I also need a minimum of flight hours with a commercial pilot certificate?


texts: Did British aircraft fly at a specific speed while returning from missions during WWII?

texts:
I remember reading a whole lot ago (so I am currently unable to find the reference, sorry) that during WWII, British aircraft would return from missions at a specific speed that was unattainable from German aircraft, i.e. it was either too fast for some, or too slow for others.

This had the immediate benefit of enabling radar operators to distinguish friends from foes without the need of any additional equipment or method, they would simply compute the aircraft speed and determine if the aircraft was British or German.

Is it true? What was that speed?
Why wasn't there a German aircraft capable of flying at that speed?


texts: What are the relative internal noise levels in various aircraft?

texts:
What are the relative noise levels in various aviation scenarios for observers seated inside an aircraft? I'm sure the specifics depend on model but I'm curious if any general trends can be drawn that are model agnostic.

e.g. Let's consider the following cases for a start:

Jet aircraft e.g. 747
Jet aircraft gliding with all engines out
Helicopter
Glider
Jet aircraft with noise insulation removed
Piston driven prop. aircraft

We could rate on an arbitrary 1 to 100 (noisiest) scale. Even better, in case data is available, I'd love to see the dB values. (@vortaq7's comment below)

I suppose speed will matter so we can probably use their typical cruise conditions for each case?

One motivation is to tease apart contributions from engine vs aerodynamic noise. Another is to quantify the effectiveness of sound insulation.

I suppose most of us never get a chance to really hear an all engines out jet nor to fly in a jet with no sound proofing.

PS. This question was motivated by some comments here:

What are these green "bags" on the SSJ100?


texts: How long does the AFSP(TSA) process take from start to finish for category 3

texts:
I paid them the $130 fee a week and a half ago and I'm still waiting for their fingerprinting instructions email. If anyone can share their timeline, that would be helpful.

TIA.


texts: Are there any Airworthiness Directives for the Boeing 777 that might explain MH370's disappearance?

texts:
Are there currently any ADs for Boing 777s which would indicate the potential for catastrophic electronic system failures that might explain MH370's transponder failure and other issues?

Was the aircraft used for MH370 in compliance with all ADs?


texts: Approx 1948 Brasil Brazil Airliner...what is it? Taildragger?

texts: What plane is this? It's a taildragger, 4 blade prop, twin engine plane. The photo was taken approximately in 1948, maybe in Brazil?


texts: Which sub-scale setting may a pilot use on an instrument approach in South Africa--QFE or QNH?

texts:
I saw this question in my Instrument Rating exam and I need to know which answer is correct, A or B.
Question: As far as the vertical reference of an aircraft during the final approach segment of an instrument approach procedure is concerned, a pilot:
A. may only use the local QNH setting on the altimeter sub-scale
B. may use the altimeter with QFE on the sub-scale
So far I have looked in ICAO 8168 and the SA CATS and CARS 2011 and this is what I found:

This excerpt is from the SACAA CATS and CARS documents:

8 Approach and Landing
8.1 A QNH altimeter setting shall be made available to aircraft in approach clearances and in clearances to enter the traffic circuit.
8.2 A QFE altimeter setting, clearly identified as such, should be made available in approach and landing clearances on request.
8.3 The vertical positioning of aircraft during approach shall be controlled by reference to flight levels until reaching the transition level below which vertical positioning shall be reference to altitudes, except as provided for in paragraph 8.4.
Note: This does not preclude a pilot from using a QFE setting for terrain clearance purposes during the final approach to the runway.


texts: Intercepts and aerial combat in IMC (or my no-fly zone is full of clouds?!)

texts:
If a reasonably modern fighter was placed into a situation where they had to engage in aerial combat while in IMC (say if radar picked up non-squawking aircraft coming from a hostile military airbase toward a no-fly zone that you're patrolling, and said no-fly zone and its immediate vicinity are full of clouds), could it be done?  What techniques would be used?  Or would the fighters seek to meet each other away from the cloud cover, since aerobatic maneuvering in IMC is generally not a good idea?

Furthermore, if it was an unknown (not necessarily known-hostile) aircraft incoming, could it be intercepted in IMC, or would the intercept have to wait until the unknown aircraft emerged into VMC?


texts: How is/was RFID bag handling introduced in a baggage handling system tailored to barcodes?

texts:
I have just seen Richard Hammond's Engineering Connections about Hong Kong Chek Lap Kok (built 1998) and afterwards, Big, Bigger, Biggest about London Heathrow Terminal 5 (built 2008).

Quote from Eng. Conn.:

  Hong Kong was one of the first airports to replace bar codes with RFID tags to track bags

Quote from BBB:

  Even such an advanced [baggage handling] system [as the new one in T5] still relies on good old-fashioned Bar Codescanners.

Which made me think: Bar codes are, as far as I know, standardized by IATA, so luggage can go end-to-end through a multitude of airports on one bar code ("check-through"), but I guess when the first airport switched over to RFID, there wasn't one for RFID, so there's a bit of a hen-egg problem. How did Hong Kong airport assure that all luggage passing through it had an RFID tag?


texts: Could a kilometer of sand as wide as the runway,1 meter deep stop an Airbus A380 if it overshot the runway

texts:
An aircraft overshooting the runway could prove to be fatal.  Assuming an Airbus A380 is fully loaded at near take off speed and pilots decide its would be best to abort take off, if they slammed the brakes and they were not as efficient and they approached 1000m of sand as wide as the runway one meter or more deep placed at the end of the runway for safety in likelihood of such incidents, traveling at near take off speed.  Would the sand be able to stop the aircraft?

For the purposes of this question we'll assume the sand is either:

A. Desert sand as fund in the UAE -or-
B. Riversand


texts: Given the same engine, why install a gearbox on a turboprop but not on a turbofan?

texts:
I am reading the book Mechanics and Thermodynamics of Propulsion, by Hill and Peterson. I found out this image while reading the chapter 5, "Thermodynamics of Aircraft Engines":

Why would there be a gearbox in the turboprop but not on the turbofan? Was this just a result of a simple, quick, representative sketch? Or did authors forget to add the gearbox to the turbofan?

Later in the text, it says:

  The gearbox is necessary so that both propeller and core engine can operate at optimum rotational speed.

There it says "optimum rotational speed". Is that the speed of the compressor? The speed of the fan? Or maybe an intermediate, flight-airspeed-dependant speed? How does the gearbox know which is that "optimum speed"?


texts: The solar impulse has a massive wing span, greater than a jumbo jets. Would it not be possible to have a biplane design to shorten the wingspan(making it more practical and maneuverable)and have the wings offset so that they both capture the sun?


texts: how can i help the air force at this age if I'm only 13 years old?

texts: I'm young, 13 to be exact. I'm not old enough to join and I really want to help the brave men and women in the skies.How can I help the air force at this age?


texts: What do aircraft designers like Burt Rutan do to cheaply practice geting good at designing aircraft?

texts:
I am a new aircraft designer, and work for a small company (which doesn't have the enormous resources of a Boeing or Lockheed) so we have to work with limited resources to get good at our trade. I've been looking over different approaches for becoming a master designer, and for learning the shortcuts and tips all great designers pickup over the years of practicing their art.

From reading, it seems most good designers got their experience by essentially apprenticing with great engineers, or having the freedom to try stuff and see if it worked or not. I was thinking how a designer could get good in a small company like mine and came up with the following options:

1) Leave the company for a larger, better funded company like Boeing and come back

Pros: Have freedom to try stuff since company has the budget to absorb mistakes, and get to interact and learn from experienced engineers at company.

Cons: From all the people I talk to, nobody can take an aircraft (even a model) to full completion since the big companies compartmentalize the skills they pick up, meaning they good at making their widget or subsystem, but never work on integrating everything together to make the whole system.

2) Build a lot of R/C models to learn the fundamentals by flying, crashing, and repairing the aircraft

Pros: Get a ton of flight experience and building experience so will quickly learn what works, what doesn't work, and learn how to take aircraft from design to flight fully.

Cons: Aerodynamics do not fully scale unless the R/C models are somewhat large (around the 10-15 kg mass), which means crashes, even minor ones, cause a LOT of damage, which gets costly quickly. Replacing busted motors, shafts, wings, and the time that is needed to do this can quickly eat into any real experience.

3) Use a digital flight simulator like X-Plane or Kerbal Space Program to learn what flies and doesn't

Pros: This is the ultimate for cheapness. I can design and crash an infinite amount of times at no additional cost, as well as fly the aircraft at full scale and see all of the response characteristics in a variety of conditions.

Cons: Building the aircraft in the physical world does not mirror how its built in the software, meaning a lot of new factors (like weight gain, manufacturing inaccuracies) come into change how the actual aircraft flies compared to the simulator aircraft. Also, the simulator has limitations in its physics model, so things like stall behavior or transsonic drag will differ significantly between simulator and real life.

4) Use a hybrid system, using 3D printing, modular parts, R/C aircraft, and flight simulators

Pros: This will teach me how to take a design to completion by first designing/flying aircraft in simulator using modular parts (like in Kerbal Space Program), then print those modular parts (wing sections, fuselage sections, wing/fuselage joints, etc.) in real life using 3D printers, and assemble the aircraft at small R/C scale to fly, before finally going to full scale using the same modular parts, only scaled up. It lets me make mistakes and learn without bankrupting the project since I learn how to avoid the big mistakes while the consequences are still small.

Cons: I will need to design and build modular blocks light enough with the same performance as that in the simulator at both R/C and full scale. Also, while somewhat easy for airframe components, building engines this way would still be costly, as some combustion engines have different performance at small scales than large scales (heat leakage and manufacturing tolerances become more important at the small scale than at large scale) meaning it might cost too much to build the system of modular parts.

What option did designers like Burt Rutan use for getting good at aircraft design?


texts: Exactly what kind of radios are prohibited for passengers inside an aircraft?

texts:
I know that passengers are asked to put their cell phones on flight mode. But some carriers allow use of WLAN on-board. So, what radios should passengers refrain from using?
Also, if a person uses a GPS receiver on his/her mobile phone (on flight mode), would it interfere with the aircraft communication system?


texts: Are grass strips more dangerous than tarmac?

texts:
There are a couple of flight schools near me. One is at a large airport, they use Piper Tomahawks primarily to teach. Naturally, they use well maintained, tarmac runways to takeoff and land. This school has had no accidents in the last few years and no fatal accidents for much longer than that.

The other school often use grass strips in fields and use Ikarus C42s and Cirrus SR22T models. This school has had 3 accidents in the past 2 years, one of which involved a fatality and all of which wrote off the air-frames.

I'm pretty sure this isn't due to the type of aircraft (as globally, they all have similar safety records) nor the instructors (both schools use very experienced instructors).

So are grass strips more dangerous to use as a runway and if so, why?


texts: How does a variable-sweep-wing aircraft keep wing-mounted payloads straight?

texts:
So, a variable-sweep wing is an interesting design, but I am wondering: if the aircraft wing moves back or forward, then the payload's angle will also change. Is there a another rotating mechanism in the payload rack or wing to keep the payload straight?
For example, as demonstrated in this picture of a Tornado ADV  where the red lines are payloads. When the wing goes back it also changes the angle of the payload, unless there is another mechanism to keep the payload straight.
However, some might argue that payload isn't carried on the variable part of the wing, as on the F14 (See the link for reference).
But, there are numerous examples of aircraft that do carry the payload on the variable section of the wings, such as the Panavia Tornado ADV and Su-24 (see the links for references).


texts: Why haven't quadcopters been scaled up yet?

texts:
Why are quadcopters not flown by human pilots yet?

Wouldn't they be more stable and easier to control than helicopters?


texts: What makes snow on the wings during take off so dangerous?

texts:
What is the cause of the widely known danger of snow on the wings of the airliner? Why does it require deicing before taking off?

I cannot believe it just makes the plane too heavy, and it is not obvious if it could alter the wing shape for this to be a problem. Control surfaces may not move as commanded? Possible shape and balance differences between left and right sides when that snow starts leaving the wing?


texts: How to calculate TAS and fuel for Diamond DA20-C1?

texts:
The PoH for the Diamond DA20-C1 is here: http://support.diamond-air.at/fileadmin/uploads/Canada/Tech_Pubs_DA20-C1/AFM/DA202-C1-Rev-28.pdf.
The plane has an MT prop, and the supplement for it is here: https://static1.squarespace.com/static/59b981e8b07869d96fe0c365/t/5e457224a5db6b6a6ce00bc2/1581609513640/DA20+MT+Propeller+Supplement+%283%29.pdf.
I need to calculate fuel consumption and TAS under the following conditions:

8000' pressure altitude (PA)
2600 RPM
-1C OAT

There's two charts in the supplement that I think I need to solve this:

It seems I need to use the first graph to find the density altitude (DA) from the temperature and PA. So for -1C and 8000, the DA appears to be 8000 as well. Looking at the table, this would give me 7.1 GPH and 132 TAS. Is this correct? I'm confused by the "standard temperature" heading in the table.


texts: Can small RC aircraft utilize a steel sheet monocoque construction?

texts:
I have seen small RC aircraft built from just about everything: cardboard, sytrofoam, fiberglass, aluminum, coroplast, etc.

Most these designs are at least partial monocoque designs. Is there any reason why sheet steel cannot be used? In comparison to aluminum, thin sheet steel is very cheap or even free. Most appliances in the US are built from approx. 1/32 inch sheet steel. It can be worked using standard tools available in a hardware store.

Are there any requirements that sheet steel would not be able to meet? I am aware that the weight-to-lift ratio of the aircraft is likely to suffer, but as long as it is capable of flight I don't consider this as much of a problem.


texts: What justifies a biplane over a braced monoplane?

texts:
Biplanes became the first airplanes to enter service due to their structurally efficient design being more suitable for the weak materials then. This efficiency comes from the two wings acting as the chords of a very deep truss.
Another structurally favorable factor was the reduced wingspan and thus moment allowed by distributing lift across stacked wings.
Yet another weight saver was the reduction of wing loading, which enabled thus use of less powerful engines for slower flight.
However, the extra wing only produces 20% more lift with 100% parasitic drag increase. Ironically, this interference drag is even more severe at the lower speeds which biplanes are optimised for.
A braced monoplane has most of the structural advantages of a biplane, with less of the aerodynamic disadvantages. So it would seem to be a more logical design than a biplane, given the same materials and engine.
Yet biplanes were built in large numbers. Why?


texts: What is the difference between turn rate and yaw rate in aircraft?

texts: Attitude heading computers generate both a turn rate and a yaw rate. How are these different from each other? Is Euler yaw rate the same as turn rate?


texts: Can perfect turn coordination automation be achieved by linking rudder to aileron?

texts:
I was reading about the ERCO aircraft which apparently has a rudder-aileron linkage system that enables co-ordinated turns without the need for explicit rudder inputs. I've heard of Piper's having bungee cords for the same purpose.

Two questions:

Does such a physical linkage lead to perfectly co-ordinated turns under all conditions? Or is it only a coarse approximation & a skilled pilot can execute a better turn?
Why don't a lot more civil aircraft automate this co-ordinated turn feature? Is it because it is hard to automate or more that one wants the pilot to retain the ability to slip when necessary & execute un-coordinated turns sometimes?

Well, even if the latter were true, since 99% of all turns are co-ordinated one could just offer an override for the automated co-ordination feature, right?

A physical linkage is rather crude, but with a servo / feedback loop wouldn't it be possible to entirely eliminate the rudder pedals?


texts: Can a flight attendant have only one eye?

texts: I have only had one eye for many years and was a flight attendant before it happened now have received a one on one interview with airline. I just wonder if my eye will be a problem.


texts: How much electrical power does one generator produce on a large turbofan?

texts:
From my related question, now I want to know just how much power does the generator produce? In other words, what is the max rating of the generator? It looks so small and that surprised me, but since it spins very fast it could get high power in a small package.

The generator from any large turbofan is fine. The answer will also help us figure how much electrical power a large commercial airliner could need at any given moment.


texts: How does the engine wash improve engine performance?

texts:
According to maintenance manual, we usually carry out engine wash (CFM56) with pure water as scheduled task. Pure water is injected into the engine from the LP compressor inlet while the engine is cranked.

I wonder if the engine performance would improve significantly after having a wash.
What is cleaned from the engine gas path? is it carbon residue or something else.

As it is said that the water should be injected at 1 o'clock position on the LPC (aft view), why does it need to be at that specific position? does it clean certain components at that position?
Thanks for your explanation.


texts: What is the purpose of the black paint below the cockpit windows?

texts:
Today I saw the following picture of the B747-400 SuperTanker, which shows a black painted region below the cockpit windows.

I have also seen vintage pictures of other aircraft that also had this black painted region.

What is the purpose of the black paint? Is it for decorative purposes?


texts: Does ICAO require (or suggest) set of technical statuses of radar and its subsystems? In other words is it required that radar status can be set to Normal, Warning and Error, or Idle, Alarm, Unknown also possible? There are 002 and 034 categories of ASTERIX which describe messages about radar status, but I haven't found out answer on my question.


texts: If you're flying VFR in controlled airspace and in contact with ATC, do you need permission to change altitudes?

texts: I think the controller sometimes gives altitudes for VFR traffic to fly, but do pilots actually need permission to change their altitude?


texts: Does the F-22 (or any other stealth aircraft) carry chaff?

texts: Considering it is nearly undetectable on radar, it seems like it wouldn't have to worry about radar guided missiles; in addition to this it is sure to have sophisticated jamming capabilities. So why carry chaff? Just weight.


texts: How to calculate the real Ground Speed from True Air Speed?

texts:
In most of the formulas I've found online GS = TAS + Vw, i.e. true air speed plus wind.

However, on the simulator, GS changes drastically if I dive or climb which is obvious because I'm covering 0 ground distance if I dive vertically.

What is therefore a real GS formula from TAS? It has to take into account the wind (Vw) but also the "3D angle of the aircraft" (for the lack of better expression).


texts: What permits are needed to operate a human-flying drone in the United States?

texts:
Casey in Finland.

If Casey Neistat were to be flown with the human-flying drone in the United States, what licenses / permits would be required from the FAA to make it legal?

All aircraft categories in the FAA assume that the pilot is inside the vehicle. Drones are operated remotely by an operator which is not carried in the vehicle, but drones are unmanned. Is there a regulation for "drones which carry person(s) while operated remotely by an operator"?


texts: Is there an Instrument Flight Procedures database in digital format such as ARINC 424 for Germany?

texts:
I am aware that Eurocontrol has an online repository for charts related to Europe's Instrument Flight Procedures. However, I am trying to find these data coded in a digital format such as ARINC 424 or something similar, especially for Germany. The ideal situation would be something similar to FAA's Coded Instrument Flight Procedures.

Could someone point me in the right direction? I also tried to check Jeppesen's website (link) but I keep receiving a "Page not found" error.


texts: Is it possible to continue flying without electric power?

texts:
To be specific with the question, I would like to know if if it is possible to continue flying in the event of total loss of electrical power. Obviously, I know this entails the shutting down of engines which would discontinue the ouput of thrust, therefor disabling the aircraft's ability to safely climb and maintain altitude. So, in technical terms, the aircraft would therefor be gliding rather than flying, but I would still like to know if its possible to do so without any power (primary or auxiliary/emergency, although having absolutely 0 power is extremely unlikely).
Here is my question: Is is possible to control an aircraft with absolutely zero electricity midflight? I also understand that smaller planes can be controlled purely by the hydraulics systems, but does that also apply to larger aicraft such as the Boeing 747, Airbus 320, etc.?


texts: Is there a fixed-wing aircraft that uses a scissor propeller configuration?

texts:
(Source: primeportal.net)

Has there ever been a fixed-wing aircraft whose propeller is in a scissor configuration? Like the Apache's tail-rotor seen here: What are the benefits of a non-orthogonal (scissor) tail-rotor?

This configuration improves the thrust and reduces the noise. If not, what are the drawbacks for such configuration when used for forward thrust?

The nearest match I could find was a stacked non-counter-rotating propeller. Not being coplanar is the only matching feature. It was on a modified Junkers W 34:

(Source)


texts: Why are the B-47’s inboard and outboard engines mounted so differently?

texts:
The B-47 has six underwing GE TG-190 engines, two on each inboard pylon and one on each outboard pylon.

The inboard engines are mounted on a long pylon that extends well below and forward of the wing, such that the inboard-engine tailpipes are (longitudinally) just about even with the wing’s leading edge.

The outboard engines, in contrast, are mounted on much shorter pylons and fit snugly against the underside of the wing, with their tailpipes extending aft of the wing’s trailing edge; they’re placed so far back that their pylons even protrude beyond the trailing edge.

(Image originally by the United States Department of Defense, via Balcer at Wikimedia Commons; modified by me.)

Why the long pylons and forward mounting for the inboard engines, versus the short pylons and rearward mounting for the outboards?


texts: What was the record for the highest man-made flight before Gagarin's spaceflight?

texts: My recent conversation with uhoh reminded me of something which stays kind of unmentioned in history of air and space flight, namely the altitude record prior to Gagarin's Vostok 1 mission. I wonder what the highest human flight had been before the first spaceflight occured. There's a Wikipedia list on (airplane, helicopter and balloon) flight altitude records: Flight altitude record, which but is quite muddled up. From the list I conclude that Iven Kincheloe's Bell X-2 flight on Sept 7, 1956 was the altitude record until Vostok 1, Kincheloe having reached an altitude of ~126,300 ft (~ 38,5 km). Am I right and why does it remain so unmentioned, somehow? I mean like it was the highest flight until Vostok 1 and the highest airplane flight until the ones of the X-15.


texts:
Yesterday I flew from San Diego to Boston in a commercial 737 operated by Alaska Airlines. Before landing we spent almost an hour circling. When we finally landed, many passengers were surprised to learn that we were not in Boston; we were still 90 miles / 150 km away.

The flight attendants told us the pilots had been too busy to announce the diversion. When the captain finally made an announcement on the ground, he said we had been redirected because the wait for Boston was 60 minutes and "we only had about 10 minutes of fuel left."

The cause was snow in Boston. Many flights were cancelled. However, visibility was excellent where we were and the flight was smooth. So I was surprised that we were diverted.

According to flightaware, we started circling at approximately 4pm; we were diverted at 4:48pm and landed at BDL at 5:03pm. Our scheduled arrival time was 5:06pm. (We departed on time.)

Below is the flight path (source).

I was hoping that some people more knowledgeable than myself could help me better understand what was going on.

Does "10 minutes of fuel left" mean 10 minutes until empty or 10 minutes until it becomes urgent? I find it hard to believe that there was so little reserve fuel, especially given that we were in the air for the scheduled amount of time.
Would this situation count as a fuel emergency? Was it comparable to this incident?
How low do commercial jets normally go fuel wise? In particular, how common is it to have 10 minutes of fuel left when landing?
Can I find out more information about my flight online? I only know of flightaware. Is it possible to find ATC radio recordings?


texts: How do I pay fees if I don't even land at the airport?

texts:
So let's say I'm going from Wellesbourne (EGBW) to Coventry airport (EGBE) and at Coventry I do 1 ILS approach and go missed and return back to Wellesbourne.

Even though I never put a wheel on EGBE how will they collect the fee for doing the ILS approach? (Yeah I know... you gotta pay for an ILS approach... yuk.)


texts: What does it take to enter the Red Bull Air Race?

texts: Starting from being a newly minted private pilot, what are the steps I would have to accomplish in order to eventually qualify for and compete in the Red Bull Air Race? Assuming I put most of my time into the endeavour and progressed at a reasonably fast pace, how long would it take me?


texts: Where do I land if I fly from KLAX with a constant east heading, crossing the US and the Atlantic ocean?

texts:
Los Angeles KLAX and Casablanca GMMN (Morocco) are at the same latitude.
If the aircraft follows a magnetic 090° heading, the initial true heading will be 102° due to the declination.

(source University of Alabama.)

That means the path will start slightly southerly.
What will be the path followed until reaching a continent on the other side of the Atlantic?


texts: Do Instrument Landing Systems restrict building heights and can these be overcome?

texts:
A recent territorial spat between the countries Malaysia and Singapore over an ILS implementation made me curious. I'm interested in finding out about ILS and how an implementation of one would affect the surrounding urban restrictions.

In that specific example, one country is saying that the ILS implementation would stifle its economic growth by restricting building height if the flight path went according to the yellow path showed on this picture

The question is, can the ILS still work if the flight path is altered to, say, an angled landing going through the water (along the thin white line) from North to South? Is it possible for a plane to turn and land into the airport (and bypass the land, hence removing building height limits) while still benefiting from the ILS in this case?

Note: The airport is 2km away from the other side of the shore (which is a separate country)


texts: Will increasing the wing area result in higher aircraft range?

texts:
Intuitively, it seems that a low loading (large area) wing will allow to climb higher from the start, thus increasing true air speed and range.
At the same time, a low loading wing also calls for a slightly lower cruising speeds due to higher lift produced, and has higher drag.
With all other things being equal (same fuselage, same amount of fuel, same engines) will increasing the wing area alone (by increasing the aspect ratio of example) result in higher aircraft range?


texts: What is a "high-bypass geared turbofan," and why is it so much more efficient?

texts:
According to the article Bombardier’s CSeries Gamble Is Facing Longer Odds, this new plane from Bombardier uses a new engine technology that will improve efficiency over its rival 737 series and A320 series airplanes, to the point where it will be able to complete on a seat-mile efficiency basis with larger airplanes, enabling it to bypass hubs:

  The linchpin for the CSeries was a new concept for engines developed
  by Pratt & Whitney, known as a high bypass geared turbofan. The new
  engine design promised exceptional fuel savings of up to 20 percent
  and unusually low noise levels.

What's the theory behind this new engine, and what are the underlying numbers that make it competitive with larger airplanes?


texts:
How do we define 2D and 3D thrust vectoring?
What are the differences between the two?
Is there anything called 1 D thrust vectoring?


texts: Can the HAL Lca Tejas perform Pugachev's Cobra maneuver?

texts: Can any variant of the HAL Lca Tejas (either the naval variant, the mark 1, mark 2 or later) perform Pugachev's Cobra?  If not, why?


texts: Is it possible to fly horizontally with zero angle of attack?

texts:
If an aircraft has a zero angle of attack and the wing doesn't, is it possible to fly horizontally? Because as the book says, there is no lift in this condition,

Is this zero angle of attack of the airframe or the aerofoil?

Can you give a simple explanation?


texts: What is the FAA definition of "takeoff" and "landing"?

texts:
This question is in the context of commercial flights with passengers.

What is the definition of "takeoff" and "landing" phases? Does it include taxi? Is it from lift-off for takeoff? and touchdown for landing?

A link to the official document would be much appreciated.


texts: Why is the takeoff decision point based only on speed and not time or distance?

texts:
The go/no go decision on takeoff for airliners is calculated as a V1 speed. The question is, why is there no time or distance for V1 calculated. In other words, if we don't reach V1 in X seconds or by X point on the runway the takeoff is rejected.

An example of where this might have prevented disaster is Air Florida Flight 90. The engine inlet probes were frozen, resulting in an inaccurate EPR reading. This caused them to set thrust much lower than they should have. They reached V1 and VR but with degraded lift, due to icing, they were not able to climb over the bridge. The FO felt something was wrong, but the captain told him it was fine and called V1.

The chain of events leading to this accident was very long and full of bad decisions. But had there been a hard and fast rule that if V1 has not been reached by this point then reject takeoff, the chain could have been broken.

Another example of where degraded performance resulted in too long of a takeoff roll is the Lokomotiv YAK-42 crash, although it doesn't appear they even had a V1 speed calculated either. They weren't accelerating fast enough, but the captain carried on expecting it to lift off at any moment. They went right off the end of the runway before it did. The reduced acceleration was obviously not enough to make the captain reject right away and by the time it did become obvious he was out of options.

There may be an unknown number of runway excursions where there was degraded performance and the crew did reject takeoff, but too late to stop.

If an engine has a problem it may continue to function in a reduced capacity then finally failing after V1. The procedures call for continued takeoff after that point, but they may have used up too much runway already.

There are myriad things that can cause degraded performance on a takeoff roll. Anything from tires, brakes, engines to flap configuration, even runway condition can slow you down and it may not be obvious that it's occurring. Many of these things won't show up on an instrument scan or a checklist. It just seems like there's no specific guidance as to how long you wait for V1. How does a pilot know when it's time to call it off?


texts: What should a Pilot do if they encounter foreign military jets?

texts:
Say you're flying an amateur-built plane just out over the waters of, say, Alaska. And then you encounter a fleet of maybe 5 foreign military jets directly above you, and then you get radio transmissions from the group in Russian. Well, what should a pilot do? The pilot doesn't understand Russian and is clearly not over any foreign airspace as the pilot is flying less than 20 miles south from the shores of Alaska, which shouldn't be somewhere that foreign military jets should be scaring pilots.
Would heading back to shore really be a good idea? The jets could potentially be hostile. So, what would be the wisest decision in this sort of scenario?


texts: How much does it cost to design a jetliner's wing?

texts:
The cost of designing a brand new wing for a jetliner, compared to modifying an existing one—with or without the changes to the production line—how is it estimated?
Related questions that come to mind: Are there various methods? Does the cruise speed (wind tunnel cost) and MTOW (size) affect the cost?

Context to prevent an XY problem:
MD-11 uses DC-10 wing to keep unit cost down; subpar initial performance
Speaking to Flight in 1987, Gary Smythe, chief customer engineer for the MD-11/DC-10, talked about the reason behind the minimal changes to the MD-11 wing compared to the DC-10.

To have gone for an all-new wing design "would add $10 million a copy to the price of an MD-11." That course of action would defeat the whole Douglas "low total ownership cost" approach.

Given that they projected 300 sales, that means the design (and manufacturing changes) would have cost \$3 billion (\$6.5 billion in 2017). The MD-11 had subpar performance for the Pacific market early on, and that was one of the reasons attributed to its low sales.
MD-90 uses MD-80 wing; subpar performance; rewing announced too late
The same thing happened with the MD-90 with its MD-80 wing. Because of this and despite having a cleaner wing of same area, same engines (V2500), and about the same seats as the A320, it could not achieve transcontinental range (both for the US and Europe), and it had longer takeoff runs.
An expensive re-wing was announced in Farnborough 1996, but was awaiting to be "sanctioned". There is no mention of the projected cost.

"It would be an all-new wing, not a revised version of the present one," says the president of MDC's Douglas Aircraft division, Mike Sears. The present wing design is a revision of the MD-80 wing. The MD-90's range is limited to intra-continental operations in the USA (Flight, 1996).

Only a few months later Boeing merged with MDC.
(Own work via boeing.com and airbus.com) Comparing the MD-90 and A320 wing and planform. Note that the MD-90 is one seat narrower.


texts: Can the fly-by-wire system of a modern airliner handle an unstable condition?

texts:
According to this answer airliners/large passenger aircraft such as an A320 are designed such that they are longitudinally, statically stable under normal flying conditions.

What if, for some reason, the c.g. would suddenly shift just aft of the neutral point? Could the FBW system of (for example) an Airbus handle this, just like the FBW of a fighter jet which is unstable by design?

Of course I'm not talking about a situation where the c.g. ends up so far back that the aircraft enters a deep stall, but a condition just "after" neutral stability, where the aircraft has just become "slightly unstable".


texts: Is it possible for ATC to see who’s transmitting on the radio on their radar?

texts:
I don’t think ATC currently has the capability of seeing who’s actually transmitting on the frequency.

If technology permits (probably by making a connection between the radios and the transponder), would it be helpful for controllers to be able to know the actual aircraft that’s transmitting on the frequency through their radar?

Does it also have the possibility of eliminating the requirement of saying the callsign after each transmission (might help in extremely busy airspaces)?

The visual aspect would be similar to how the “ident” feature works (like seeing a little “TX” when someone is transmitting).


texts: How do composite aero structures compare against metallic structures in crash resistance?

texts: is there any information available comparing the difference in crash resistance between composite mainly carbon or fiberglass polymers etc vs conventional metallic mainly aluminum aircraft structures.


texts: Can a passenger request to visit the cockpit during a flight?

texts:
As a kid, I remember going to the cockpit of a plane with my mom (I believe the airline was AOM French Airlines).

Is this still possible now?

I understand the answer might differ with different airlines/countries, I'm mostly interested in European and Asian airlines/countries, specifically Japanese.

Is there some specific regulations for international flights, or does it depends on departure/arrival locations?


texts: What is the weight that is used to balance an aircraft called?

texts:
I remember I was reading about balancing an airplane a few days ago, and i came across a type of weight that is added to balance the airplane. But, I do not remember what it was called.

Also could someone tell me the approved location of these weights on a Boeing 747-400?


texts: Is 1N2 (Spadaro) in class G or D airspace?

texts: I am confused about the situation where an airport is located in class G airspace and at the same time located in class D airspace. As we can see the picture below Spadaro (1N2) is located inside the Francis S Gabreski (KFOK), am I right? If so, do I need to call tower before entering class D?


texts: Placement of positioning lights on A320 winglets

texts:
I was flying with an A320-214 that had big winglets (I think they were called Sharklets). I noticed that the positioning lights were facing forward on the leading edge of the winglet (the "notch" in the picture).

I was wondering why the light is placed there, because it seems to be very unoptimal.

Isn't the light mostly blocked when viewed from behind? Why is not not placed at the top of the winglet? Is that even a big concern?


texts: What does a sport pilot have to do to get a private pilot certificate in the US?

texts:
What are the minimum requirements for obtaining a privates pilot certificate if a pilot  already has a sport pilot certificate?

The requirements for a private pilot certificate don't changes because you already have a sport pilot license. However by successfully obtaining a Sport Pilot certificate, you should have already completed some of the private pilot requirements.

How much of your sport pilot training counts towards your private
pilot license?
How much of the training will have to be re-done?
Does it depend on
the type of your flight instructor's certificate?


texts: Why was the An-225 built when the VM-T Atlant already did the job?

texts:
The Soviet Buran program decided to use a carrier aircraft to move their orbiter and Energia tanks similarly to the American Shuttle Carrier Aircraft. However, the Soviet Union built two types to do the job.

The famous An-225 project was started early, but they also decided to build a backup aircraft based on a Myasishchev 3M bomber. This aircraft, the VM-T Atlant, was finished much earlier. Since the An-225 wasn't ready yet the Atlant played delivery truck for the initial and only Buran launch.

Of course the An-225 is much more capable than the Atlant, but if the Atlant can do the job why go through the effort and expense of developing a second massive airplane?

Further reading on the VM-T Atlant.


texts: What happens when an aircraft is hit by lightning? (Assuming that none of the engines is hit). Is there some FAA regulation (or some other regulation) which makes it mandatory for aircraft manufacturers to ensure that minimum damage occurs to the aircraft when it's struck by lightning?


texts: Is a full traffic pattern required when there is no traffic at an untowered airport?

texts: If there seems to be very little traffic at an untowered airport, and no one's replied to any of your radio calls, is it acceptable to just fly a straight-in approach to the runway, or should you still fly the full traffic pattern to final? It just seems like it would be a waste of time and fuel when it's not really necessary. Is there anything wrong with doing so?


texts: Is there any form of checklist that a pilot needs to go through before they use their ejection seat?

texts:
Obviously, the use of an ejection seat is a last resort tactic but is there anything at all that a pilot must consider, any buttons they need to hit or something similar before they may eject?

Obviously not including anything such as arming the ejection seat or removing any covers over the ejection seat handle or anything.


texts: What does the autopilot do if activated in a stall condition?

texts:
I was thinking about Air France 447 recently and had a wonder:
What would happen if the pilots had re-engaged the autopilot and stopped all stick input? (If that's even possible in a stall condition). I know this has since changed, there is the MCAS system now, which will force a stall recovery. But in an older aircraft, like the A330 - 203, what would happen?


texts: What are ATC's considerations when they instruct to intercept final approach course instead of simply clearing for approach?

texts: When ATC provide radar vectors for an instrument approach, they sometimes instruct pilots to intercept the localizer or final approach course before giving an approach clearance, and other times give an "early" approach clearance with the final vector for the interception while the aircraft is still heading to intercept the localizer or final approach course. What are ATC's considerstions when they "delay" the approach clearance until the interception of the localizer or final approach course?


texts: How many Inertial Reference Systems are on a commercial aircraft?

texts: Nowadays all new airplanes have GPS on board so the use of IRS may lose  importance, still they must be fitted. How many of them are usually on a commercial aircraft? Does the regulation impose the number?


texts: Where do the forces exerted on flight yoke/stick comes from and how do they vary with flight conditions?

texts:
What are the forces felt on the flight yoke/stick based on the deflection of control surfaces and the aerodynamic forces acting on the control surfaces with respect to different aircraft attitudes?

For example: At low airspeed, the controls usually feel soft and sluggish, and the airplane responds slowly to control applications. At high speed, the controls feel firm and the response is more rapid.

Are there any equations that represent the same and how is the force exerted on the flight control yoke calculated?

My question is based on the control loading system of professional grade flight simulators for general aviation aircraft. I want to design a force feedback mechanism for a flight simulator to enhance realism.


texts: What are the safety concerns and efficiency benefits of two in-line runways?

texts:
Heathrow Hub is an independent proposal to expand capacity at Heathrow Airport by extending both of the existing runways up to a total length of about 7,000 metres and dividing them into four so that they each provide two pair of full length, in-line runways, allowing simultaneous take-offs and landings.

How to ensure the planes landing and take-off in the same runways safety?
How many flight can be handled by such design, and how efficiency it is compared to two runways using segregated parallel operations (one for landing and another for takeoff)?


texts: For subsonic aircraft, would adopting a higher wing loading decrease drag?

texts:
First, let's assume that problems with approach/TO speeds can be fixed by high-lift devices.
Here we read that the wings create more drag than the fuselage. So, an improvement seems obvious; shrink the wings.
However, for a given weight, altitude, and airspeed, such a wing would need to fly at higher angle of attack, creating more induced drag. How does this compare against reduced parasitic drag?
If one wants to reduce induced drag, than one must fly at lower altitude. This means more parasitic drag - again. But does the former outweigh the latter?
Induced drag can be reduced further by the weight reduction from a smaller wing. How does this compare to the above?


texts: Why is there typically a large gap between the first flight and mass production of aircraft?

texts:
Here are some examples I've found on Wikipedia:

Me-262: first flight 1942 July, introduced 1944 April.

MiG-19: first flight 1953 Sep, introduced 1955 March.

Dassault Mirage III: first flight 1956 November, introduced 1961.

F-4 Phantom: first flight 1958 May, introduced 1960 December.

This shows a two or three or even five year gap between the first flight and the entering into mass production.

Why such a long gap? What goes on during those years? To me it seems like once the first flight is done, it "works" and the only thing left is some finishing touches. Is it possibly more a matter of setting up a factory?


texts: Can a helicopter be stable without moving the control inputs?

texts:
I have only flown helicopters in a flight simulator (X-Plane) and I have found it exceedingly hard to fly in certain regimes (especially hovering and close to hovering) because it seems like there is no point on the controls at which I can stay and not have the helicopter start moving in a direction I want.  As a result, I wind up having to constantly move the control inputs (cyclic and yaw) in small amounts back and forth across where the stability point should be.  On flight simulator forums I have actually seen a couple of people recommend doing this.
But my question is, does this accurately reflect how a real helicopter behaves?  Is it possible to maintain a stable hover or slow speed movement in or out of ground effect once achieved without moving the control inputs much or at all?


texts:
I understand why JetBlue's IATA code isn't JB since that belongs to a pre-existing helijet service in Canada, but why is it B6?

Is there some history behind the B6 moniker?


texts: Can a handgun shot take down a commercial airliner?

texts:
Most airplanes, when taking off or landing, are in range of small arms fire, i.e. your every day handgun.

Is it possible to take down a commercial airliner by shooting at it with a handgun? Would one shot be enough, or would several be needed?


texts: Is there a good online source on rotating detonating pulse engine?

texts: I can't find a clear presentation that would explain the workings of a rotating pulse detonation engine graphically, only useless (to a layman) cfd simulations of the combustion chamber. Please share if you know a good online source to learn about this design.


texts: What is the energy demand of a secondary surveillance radar?

texts: I'm writing a report to see if it's feasible to power a secondary surveillance radar with wind energy. I'm having trouble with sizing the turbine but I can't seem to find an energy demand for a SSR anywhere. any help is appreciated.


texts: Does the airports have there own incident/accident investigation depts? or they are restricted to the NCAA/Safety dept only?


texts: What is the relation between throttle position and engine thrust for a turbofan?

texts:
I wonder how is designed the command chain from the throttle lever or the auto-throttle to the fuel injection in recent jetliners. I have 4 questions:

What is set by the throttle?

When the pilot actuates the throttle, what are they setting exactly? (I can imagine the lever position corresponds to a fuel rate, to a RPM, to a thrust value, etc).
Is this value a linear function of the throttle position (e.g. 73% of the full lever rotation is 73% of the maximum N1).

Is the throttle output standardized or customized for an engine model?

What type of output has the throttle lever: mechanical, electric, digital data?
Which subsystems in the engine receive the throttle output(s)?
Is this output customized/calibrated for an engine model, or standardized.

How are the throttle outputs processed in the engine?

Does the electronic engine control apply further adjustment to the throttle input?

How does the auto-throttle (auto-thrust) interact with the manual throttle?

Does the auto-throttle send its command directly to the engine or to the mechanical throttle?
Is the manual throttle position adjusted, according to the A/T output?


texts: Could a high absolute difference between heading and course give a hint about weather conditions?

texts:
I am developing an application that tries to predict the future track of an airplane. At the moment I don't have access to weather data and I am trying to find a metric that could substitute that.
If I am not wrong, a pilot should change his heading according to wind's direction in order to maintain the airplane's course to the target airport. So If the wind benefits the airplane's movement, the absolute difference between heading and course should be zero most of the time. Is that true? If not is any another way in order to get a hint about weather conditions from heading/course information?


texts: Did I witness an engine test for a 757 at MAN?

texts:
A while ago (Summer 2020) I was walking near MAN airport (UK) and saw a 757 taking off. There was a peculiar event during takeoff and I'd love to know what it was.
Once airborne at about 1000 feet (complete guess) its starboard engine started showing flashing rings of flames and there was a loud repeating banging sound for about 20-30 seconds. The plane continued to climb up to several thousand feet.
While watching this I opened FlightRadar and saw that the flight's destination was also MAN.
Over the next 30 minutes or so the plane did a few laps and presumably came back to land.
I'd love to know what this event might have been?


texts: Is there a checklist for lightning strike?

texts:
Is there a specific checklist or procedure to follow, after a confirmed or suspected lightning strike on the aircraft?

Or is a basic scan around the cockpit (plane is flying, no warning lights, no circuit breakers popped) sufficient?


texts: Would flying below FL285 be feasible for aircraft that don't comply with EASA CPDLC?

texts:
I am not a pilot, my understanding about flight is limited.
EASA CPDLC will require airplanes to be capable of PM-CPDLC data communication to fly above FL285.

For an airline with multiple 767-300 and 757-200 airplanes, would it be feasible to consider the option of flying below FL285 in European airspace, instead of ceasing operation in the region or investing millions of dollars for avionics upgrades?


texts:
Looking up numbers for my answer to the A380 production question, it occurs to me that Airbus is facing a real inability to deliver its latest airframes. The A380 is currently sustaining a build pace of 45 aircraft a year with a backlog of about 150 outstanding orders. The A350, Airbus's direct competitor to the 787, has better orders (781 outstanding), but Airbus has been able to deliver only 5 of those, 4 to Qatar Airways and 1 to AerCap. The A340 ended production in 2011, so the 330 (1370 orders, backlog of 356)  350 and 380  are Airbus's only three widebodies in production right now. The 320 and 321 are backlogged badly, though Boeing has a similar backlog for 737 variants so that seems par for the course in the modern aviation industry dominated by LCCs.

Boeing has had fewer orders for its 747-8 but is keeping pace (92 delivered of 123 ordered, averaging 18 airframes a year) and has an embarrassment of riches in 787 orders (1095 ordered, 295 delivered, on pace for about 115 aircraft a year after ramp-up) and healthy business with the older 777 (backlog of 560, in the ballpark of about 80 deliveries a year since 2010). Its 767 frame, a close competitor to the A330, has slightly fewer orders despite being the older plane, but Boeing seems to be keeping pace (less than 100 backlogged in a total of 1161 orders).

I read these numbers and I come to the conclusion that Airbus is in big trouble in the large and very large jet markets it was planning to dominate just ten years ago; Boeing, by most accounts seems to be out-producing them and thus getting the lion's share of a mostly post-jumbo market. Am I reading this right?


texts: Can the cockpit windows on commercial airliners open during flight?

texts: I  observed that the cockpit windows on the commercial airliners actually open - good for a hot day while waiting on the airfield, I suppose. Is there a mechanism which prevents the window from being opened when airborne?


texts: What is the minimum stopping distance for a 747-400?

texts:
Im looking at purchasing  disused 747-400:

The aircraft will be stripped of all seats and other non essential items.
The aircraft will be then flown to my property in Victoria, Australia and perform a one off landing.
The landing distance would be between 1500-2300 feet.

Can this be done?


texts: Since there are no toilets on smaller aircraft, how do you deal with the inevitable?

texts: How do you handle business on a small plane on long flights? For example a cross country in a C-172.


texts: If airliners profit by moving luggage from checked to carry-on, why do some LCC gate-check luggage?

texts:
According to this answer, the less luggage is transported as checked luggage, the more "room" (in terms of weight) there is to bring along cargo, and thus more profit.

At the same time, some LCCs have the practice of gate-checking a bunch of bagage, essentially moving stuff from carry-on to checked luggage. It seems to me that that too is motivated by profit. But I'm not sure how.

These two practices seem to be contradictory, since they move luggage in other directions. While I can see the profit in the former, I don't directly see it in the latter. So what is the LCC's motivation to gate-check luggage?


texts: Why is the Constellation's nose gear so long?

texts:
The Lockheed Constellation has an enormously long nose gear, which causes the aircraft to slant appreciably backwards when sitting on the ground:

L-049

(Image by Greg and Cindy at Flickr, modified by Cobatfor at Wikimedia Commons.)

L-649

(Image by the San Diego Air and Space Museum, via Flickr, via Wikimedia Commons.)

L-749

(Image by RuthAS at Wikimedia Commons.)

L-1049

(Image by RuthAS at Wikimedia Commons.)

L-1649

(Image by Robert Togni at Flickr, via JuergenKlueser at Wikimedia Commons.  Note that, due to the gigantic nose gear, the fuselage is approximately level, despite the ground sloping downwards considerably towards the aircraft's nose.)

In contrast, other airliners of the era had a much-less-ridiculous nose gear length, like the DC-7:

(Image by Ted Quackenbush at airliners.net, modified by Fæ at Wikimedia Commons.)

and the Stratocruiser:

(Image by Bill Larkins at Flickr, via Wikimedia Commons.)

Why is the Constellation's nose gear so much longer?


texts: Is it possible to design an aircraft as big as A380 with 2 engines?

texts: As it is generally seen, 2 engines are more efficient than 4 engines. So, can we have so powerful engines to design an aircraft as big as A380 with 2 engines?


texts: Are two little engines or one big engine more efficient for an ultralight?

texts: For an ultralight, should two engines weighing 10kg each and making 7hp each OR one engine weighing 20kg and making 14hp be used?


texts: How can I correctly decode CPR positions from ADS-B frames?

texts:
I am decoding Compact Position Reporting (CPR) positions from ADS-B frames (the airborne position and surface position frames).

Most of my results give realistic longitude/latitude values, but some return things like 0,781518968485169 177,220642089844; or 1,76377118644068    -0,664306640625; or 2,12129237288136 -2,838134765625.

I have a feeling like I must be missing some kind of validation or some kind of frame type identification. Where can I find more information about the decoding process?


texts: Is overall pressure ratio same as compressor pressure ratio for a gas turbine engine?

texts:
For a typical gas turbine engine, turbofan in particular, is the compressor pressure ratio same as the overall pressure ratio?
For modelling purposes can we use the same value of overall pressure ratio for compressor pressure ratio too?
If we do so, will we get accurate results for performance?


texts: Why does the vortex created by wing affects its own angle of attack?

texts:
According to potential flow theory, we know that the lift generated by the wings is due to the vortex it creates. In case of a 3D finite wing, there is also a span wise flow due to tip leakage from bottom to upper surface. So if suppose the wing is moving towards left, then the direction of vortex should be clockwise, which in turn should produce an upwash rather than downwash. This should cause an increase in angle of attack rather than decrease.

So the downwash generated should be valid for a wing travelling behind the original wing, but we say that there is downwash on the original wing.

So where is it that I am making a mistake, vortex direction. If yes, what is the correct explanation. Please explain.


texts: Are there any negative health indications from getting sea legs?

texts:
I recently completed a long XC and upon completion I suffered a bit from sea legs. The XC was for the 250nm requirement for my instrument rating and was performed in a C172. It took about 3.5hrs
 to complete and there was a short ~30min pit stop a little before hr 3 of the flight. I was under the hood the entire time except for takeoff and landing. The air wasn't particularly smooth as
we were only @3-4k MSL and surface winds were in the teens.
I completed the flight in the early evening (~8pm) and feel like I suffered from sea legs, a small wobbly sensation of constantly moving, until I went to sleep (~11pm). I'm guessing the sensation would have lasted longer had I not gone to sleep. The sensation only occurred once on the ground and after completion of the XC. I don't recall having the sensation during the pit stop.

I'm curious how or if I should be concerned about this.  I do not suffer from in flight nausea, motion sickness or anything like that.

I have never had this happen on shorter, 1-2hr, training flights.  I've never had this happen when flying on a commercial jetliner.
I remember experiencing the same sea legs sensation on another long ~400+nm XC years ago. I flew a plane with an autopilot that rocked back and forth as it held the heading and I attributed the post flight sea legs to the oscillations of the autopilot.

Is this common for pilots to suffer from sea legs post flight? If it is common, how long does it last?
Is this an indication of a pending medical issue or an issue that might be of concern?
I'm curious if this is an indication of something of concern in my inner ear.
Are there any concerns with bringing this up with my AME? I have to get my medical renewed this year.