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79

This would be an extremely difficult question to answer without being opinionated, but I'll give a try. As part of the investigation, the NTSB, along with other agencies carried out a number of tests on simulator, where pilots were tasked with either landing or ditching the aircraft. There were three different scenarios contemplated: Normal landings ...


72

Proving that an aircraft is flyable with one or more engines inoperative is part of the certification programme. The Airbus A380 is certified under FAR (Federal Aviation Regulations, USA) part 25 and JAR (Joint Aviation Regulations, Europe) part 25. One of the requirements of FAR/JAR 25 is that the directional control can be maintained when two critical ...


59

The current position of regulators like the FAA is that dropping things off of airplanes in flight is a bad thing. Dropping extremely large and heavy things like engines would be extremely bad. This poses an unacceptable risk to people and property on the ground (or even in the water). Most aircraft with engine fires do not kill anyone on board, so why risk ...


52

Qantas Flight 32 Enroute to Sydney, Engine Number 2 of the A380 disintegrated explosively. The shrapnel of the explosion destroyed many systems, including a hydraulic system, the anti-lock braking system, flaps and electronic controls. After emergency landing, the pilots were unable to stop engine number 1, because the controls had been destroyed by ...


47

One of the main reasons the 747 was given the ability to ferry an engine was due to the lack of large cargo aircraft available at the time. Don't forget the 747 was a major game changer when it came out, it was designed to replace the 707/DC-8, and was almost twice the size of these aircraft. As a result, there just wasn't anything available to transport a ...


42

All airplanes can glide, if they couldn't they wouldn't be able to fly in the first place. When you glide an aircraft you are converting height into airspeed, which you can use to move across the ground. How far you can go across the ground for height lost is called the glide ratio for the aircraft. Gliders have a very high glide ratio as their wings are ...


41

The AvHerald comment is correct, you generally do not want to turn towards the dead engine. The aircraft will tend to turn (both yaw and bank) towards the dead engine due to asymmetric thrust, allowing it to do so at low speed will make it difficult to end the turn, possibly to the point where you lose control. If you turn away from the dead engine, you'll ...


39

The image looks like four engines running at the same cruise thrust. The wake vortex is blowing the exhaust of the inboard engines down and the exhaust of the outboard engines out and in the perspective of this image this makes the lower two streams look merged while the upper ones further apart. Close behind the engines it is clear there is four of them and ...


37

One of the absolute requirements of an aircraft turbine engine (usually some sort of turbofan or turboprop) installation is that, in the event of a destructive failure of the engine, the engine cowling must be able to contain any and all fragments released in the process. No, there is not. The requirement is that the engine cowling must be able to contain ...


35

It's important to note that there were many elements of both skill and luck involved in the US Airways 1549 "miracle" landing - the NTSB report and NTSB deliberations make for an interesting day of study. We can divide your question into two different segments: 1 - Could another crew have executed this ditching after losing both engines? The answer here ...


33

All airplanes can glide. Some glide better than others. A very old reference I read talked about engine-out landings in military aircraft. Their procedure was arrive at the airfield at X feet, circle once and land. Trainers like the T-33 needed 2,500 feet, other aircraft needed 3,500-5,000 feet. An F-104, which is basically an engine with fins, needed 20,...


29

Cathay Pacific flight 780 on 13 Apr 2010 Fuel contaminated by super absorbent polymer jammed fuel valves caused engine control problems. The aircraft eventually landed with one engine at about 70% N1 at significantly higher than normal airspeed, burst some tires from the increased braking necessary and was evacuated.


28

Engines don't fail, on average. And if they do, it's a very low probability that two engines will fail at the same time. Modern jet engines are extremely reliable, with failure rates on the order of 0.01/1000hrs. And if you do have a failure, you have redundancy, as you have two (or more) engines. A plane can stay aloft and land with a single engine. It ...


28

I would not follow the advice in the forum. While the reasoning that a windmilling prop does create more drag is sound, I have seen no empirical evidence that says how much it actually translates to in Feet Per Minute. The only studies I have seen have been inconclusive on the subject, and say there's a number of factors that you can't really control in that ...


27

There's virtually no chance of the pilot deliberately switching off all 4 engines, and even less chance of all 4 engines failing at the same time. It's not entirely impossible for it to happen, but it definitely wouldn't be quietly ignored within the aviation community. I promise you that you would've heard about it afterwards. That said, the A380's engines ...


27

straight out of the Airplane Flying Handbook, pp 9-4 Operating the engine at idle speed for any prolonged period during the glide may result in excessive engine cooling, spark plug fouling, or carburetor ice. To assist in avoiding these issues, the throttle should be periodically advanced to normal cruise power and sustained for a few seconds. ...


26

Yes, all aircraft have a glide ratio. On many of the higher-performance fighters, it's 1:1 at best (1 foot altitude traded for one foot forward gliding). Many of the newer fighter aircraft are intentionally unstable. They aren't really flown by the pilot; they're flown by a Flight Control Computer System (FLCCS) which depends on electrical and hydraulic ...


26

Any time the question is "why don't we have...", the answer is almost certainly in the trade-off between weight, maintenance cost, fuel cost, & utility. If it weighs a lot, needs maintenance, burns fuel, and will only be useful once a decade, then it just is not productive. Putting rocket thrusters on a plane will be heavy, meaning fewer passengers, or ...


26

I'm sure someone else will come along and give you a better answer with illustrations and everything, but until then, here goes :) Multi engine aircraft usually have their engines off to either side of the fuselage. This means that if one engine fails, the other engine will produce what's called asymmetric thrust (one engine is stronger than the other). ...


25

The answer to your question strongly depends on what kind of airplane you're talking about (in particular, what set of rules it was certificated under), as well as the phase of flight you are in (takeoff vs. cruise vs. approach/landing) and whether you are in a jet or a (turbine or piston) propeller aircraft. (I'm going to exclude single-engine airplanes ...


24

All commercial aircraft have some form of redundancy in their instrumentation, but it's not always in the form of "analog" instruments. The backup is often electronic itself. But the overall system is designed with a very high level of redundancy. A typical modern jet aircraft has an Electronic Flight Instrument System (EFIS), which is the large screen ...


24

If an engine failure occurs above V1 the aircraft can accelerate to the Vr and take-off, retract gear and accelerate to V2 and pass the end of the runway at a height of at least 35 feet. From there, flying at V2 or above the aircraft can climb at angle that keeps it clear of nearby obstacles. Part of the aircraft's certification is to demonstrate that this ...


22

As RedGrittyBrick has commented, what happened in that video is a compressor surge. This is not really an engine fire, but a temporary backfire. To understand what is happening, look at this diagram of a turbine engine: The air is compressed in the front of the engine, fuel is injected and ignited, and then everything flows out the turbine section and the ...


22

General rule here: the engine will remain at its last power setting should the FADECs lose comms with the flight deck controls (in your A380 case) or the thrust lever cables come unhooked (in the case of an older aircraft with mechanical cable-and-pulley controls). However, the fire handle will kill the engine even if the main controls fail -- it operates ...


22

The valves will not be able to maintain cabin pressure until the plane descends to 10,000 feet at best glide speed. The oxygen masks will deploy before then. At least that was the case for Air Transat Flight 236, an A332 that ran out of fuel over the Atlantic and glided to a deadstick landing. The occurrence report on page 96 (see the table) estimates that ...


22

Maintenance costs are a big deal. Maintenance costs across multiple engine types for a fleet of the same airplane would be a big deal - training, parts, etc. Worldwide weather tracking & reporting lets pilots avoid ash, thunderstorms most of the time, and other severe weather which is rough to fly in and can leave customers rattled. I don't think ...


22

In IT more hardware is redundancy, but in aviation a liability Short answer In IT, having redundancy and diversity is low cost and no liability, but high gains in service reliability. In aviation, redundancy and diversity is high cost and a liability, for no increase in reliability of the service. The long answer The big difference is that in case of a ...


21

The airplane will no longer be in normal law mode if both engines fail and no other electrical generator is online. The airplane needs a primary source of electrical power in order to remain in normal law (among other things of course). If both engines lose power, then the generators on those engines also lose power. The only other primary electrical source ...


21

The A380 does not appear to have the capability to transport an extra engine under the wing. Higher engine reliability combined with widespread availability of air cargo transport makes this option redundant in modern jets. In case engines are needed for an A380, they can be transported in a 747-400 Freighter* or the aircraft can be flown with three engines....


20

Etihad Airbus A340-600 This famous crash happened on the acceptance engine run-up test. The causes were unrelated to engine problems, but after the crash, due to damages, two engines couldn't be shut down. One of them ran for 9 hours (!) after the incident, until it ran out of fuel, creating obvious hazard for the emergency crew. (Luckily, there were no ...


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