New answers tagged

2

Modern airliners use EGPWS (Enhanced Ground Proximity Warning System) with two sources of information for triggering warnings: the radio altimeter and a global terrain database. See e.g. the Boeing 737: Ground Proximity Alerts The GPWS provides alerts for potentially hazardous flight conditions involving imminent impact with the ground. The ...


5

Most countries have established some sort of Rescue Coordination Centre responsible for search and rescue operations in case an aircraft or ship goes missing. The RCC typically has direct access to various SAR resources such as helicopters. They can also call in local emergency teams (police, firefighting, ambulances etc.) How exactly the RCC is notified of ...


7

Apparently the pilots of ET-363 on 2020-01-09 opened the cockpit window in flight to clean part of the windscreen from the remains of a locust swarm [1]: The windscreen wipers were not able to clear the windshield anymore. The crew went around, climbed to 8500 feet, depressurized the aircraft, opened the cockpit side window and cleaned the windscreen ...


0

Organophosphorates reinforce Acetylcholine neurotransmitter's actions, by blocking its degradation, it have two toxicities: early and late, early is due to its action on neurotransmitters, late is induced by neuron lesions, and harder to treat. It is not difficult treating organophosphorate acute poisoning, as long as causative agent is clearly identified, ...


3

Most modern systems, such as those found in Air Data System, stall warning, Primary Flight Control Computers, already do bound checks on the measurement values. If an AOA measurement is outside of programmed static thresholds, typically very negative or very large, the system can either inhibit its functionality or vote the measurement out. This is pretty ...


38

Something should be pointed out here. Fume events are not related to Phosphate Ester hydraulic fluid and there is nearly zero risk of Skydrol or Hyjet getting into an air conditioning system (if there are airliners out there that use air conditioning source bleed, to pressurize accumulators or reservoirs, with an open return path back through the bleed ...


23

Skydrol was developed to provide a hydraulic fluid that does not catch fire when a fine mist of particles under pressure is released, upon a leak in the hydraulic system. Of the two evils, poisoning or burning, a case can be made to avoid the latter when considering aeroplanes. For ground based systems like full flight simulators, hydraulic systems are on ...


2

Most of the special features of a seaplane are about taking off from the water, because of the need to minimize drag. Almost none of this is useful for an airliner. When you're ditching, you're probably going to ditch on the ocean, and unless you go all-out on the seaplane design, salt damage alone is going to destroy the airplane. Design of airliners for ...


1

Aircraft usually have "disagree" warnings when redundant sensors do not provide the same reading (within some specified tolerance). This warning may (or may not) inhibit other systems that depend on those sensors. For instance, the MCAS system in the 737MAX was designed to rely on two AoA sensors. If the two sensors disagreed, the pilots were given a ...


2

Let's distinguish the two types of "hacking" we're talking about Total control of the airplane This is the stuff of Hollywood and is often over-dramatized. The new season of Dr. Who started off with a car being "hacked" and trying to drive itself off a parking deck. If you're not shaking your head, you should be. This wasn't a self-driving car, it was just ...


0

All three of the useless data are contrasts with useful information: the altitude above you What matters is how much air is below us. runway behind you We're only interested in how much runway is available in front of us. fuel on the ground We care about how much fuel is in our tanks.


6

And exactly what or how are you going to ‘sanity check’ these systems? The AoA sensor is just a sensor, converting a physical position into a voltage which another piece of hardware can interpret the results from. Now some aircraft have multiple AoA vanes so a faulty vane could be detected and isolated if its input data does not concur with other sensors ...


1

Regarding power cycling specifically (as opposed to software-based failures in general which other answers have detailed very well), it's not a problem at all. Unlike a typical PC or smartphone which takes time to turn back on and can lose data when power is lost, the control systems on an airplane are typically designed such that they will resume complete ...


0

Reboots can also sometimes be acceptable if you can reboot quickly without losing critical information. This occurred as part of the Apollo 11 landing when they had the 1202 alarm: He realized that the 1202 was a code meaning that the guidance computer on-board the landing craft was getting overloaded with tasks. The programmers had anticipated this ...


4

as somebody who did software tests on an unimportant (class D, will explain soon) system for an airplane to be approved to be landed on civilian airports: In airplane there is a strict hierarchy on what kind of software functions mean; they are listed in DO-178B. Class A systems are assumed to be "failure free"; they are extremely well tested. These ...


2

Sounds similar to the De Havilland Comet 1's other problem. On 26 October 1952, the Comet suffered its first hull loss when a BOAC flight departing Rome's Ciampino airport failed to become airborne and ran into rough ground at the end of the runway. ... Both early accidents were originally attributed to pilot error, as over-rotation had led ...


4

Occasionally a computer or smartphone will crash and reboot itself This can happen for two reasons: a software error or a hardware error. Both can cause the CPU to stop processing new instructions (i.e. a "hang") or to cause the machine to reboot itself. The latter is close to a hang, because the Operating System detects it cannot continue operating ...


24

Before we start, it's important to say that your concern is not irrational. If this were to happen, or if your plane's control systems were to otherwise malfunction in a dangerous manner, your life would genuinely be in danger. You aren't the first person to have thought of this, though. For this reason, we have a category of control systems we describe ...


2

There are a couple I can think of off-hand from the last couple of decades (in addition to the ones already listed in other answers): 1. National Airlines Flight 102 I suppose whether this one counts depends on exactly what definition of "airliner" you're using. Certainly, the 747-400 is normally considered an airliner, though this was its cargo variant. I ...


0

Ice on airplanes causes two main problems. It adds weight and drag. It changes the shape of the aerodynamic surfaces. Problem 1 is fairly obvious. How serious a problem it is depends on the airplane and how fully loaded it is. If it is a problem, then ice needs to be removed from any or all surfaces to reduce the problem to an acceptable level. If the ...


66

I'm a programmer and private pilot, so maybe I can help dispel some of those fears. The computers that run a commercial airplane are conceptually much simpler than the one that runs your phone. This means far less chance of a bug in the software, just because there's less for the programmer to keep track of. If your phone restarts, it doesn't imperil ...


10

Your concerns are reasonable and justified. A mid-air shutdown or reboot would be catastrophic to an airliner. Which is why, engineers designed the systems such that this scenario is practically impossible to happen. Electrical power An airliner has multiple electrical power source. Each jet engine has a built-in generator. When the turbine spins, ...


1

The 1972 crash of BEA flight 548 in Staines, near Heathrow Airport, London, was, and remains, the most lethal flying accident (excluding terrorism) in the UK. It was a significant incident with respect to raising issues of crisis management in the cockpit, and in bringing about the use of cockpit voice recorders. The proximate cause was a decrease in the ...


9

Engine mounts and thrust links How are engines mounted onto wings? Modern engines are hanged to the pylon struts fixed to the wings, at two mounts, using an attachment device named hanger fitting in the terminology of CFMI. This is how a CFM56-7B is mounted onto the wing of a Boeing 737 NG: CFM56-7B on the wing of a Boeing 737 NG. Adapted from CFM56-...


4

Two other catastrophic accidents during takeoff phase occurred on flight testing for transport category aircraft, though both of them are business jets: 1. Bombardier Challenger 604, 2000, Wichita Aggressive takeoff rotation led to fuel migration and shifted the aircraft CG aft of the allowed limits. The combined effect of the large initial rate of ...


3

Several examples on Skybrary One of the most notorious cases is arguably Northwest's MD-82 On 16 August 1987, an MD-82 being operated by Northwest Airlines on a scheduled passenger flight from Detroit MI to Phoenix AZ failed to get properly airborne in day VMC and, after damaging impact with obstacles within the airport perimeter after climbing to ...


13

There are two fairly recent airliner crashes I can think of that were the direct result of an aerodynamic stall, one is Air France 447 and the other is Colgan Air 3407. AF447 was at cruise height when the incident began, so that one does not fit with your question. Colgan3407 was landing, so was pretty much "low level" (Does "jet" permit a turboprop?). ...


28

The props are done before starting because you need to make sure the blades and spinners are fully cleaned off while they are stationary. Otherwise, they'd vibrate like hell when starting and shed bits of ice all over. Also, if you just sprayed the props while running the engines would ingest a lot of glycol, which, if it doesn't make the engine flame out, ...


5

Ice flying off the propellers can damage something, or someone. Also unbalances the propeller assembly overall, leading to vibrations. Little bit of ice left on the fuselage is not bad, only causes some extra drag until it sublimates off, and of course a little extra weight. Ice Will impact the lift created by the wings, that is very bad, unless the ice is ...


3

The French accident investigation board, Bureau d'Enquêtes et d'Analyses pour la sécurité de l'aviation civile (BEA), investigated this incident. The report was completed in March 2016. Among the recommendations for EASA was better medical and psychological monitoring by the aero medical examiners. Explicitly not recommended was the already mentioned ...


0

Of course you can. In terms of flying skills, assuming you’re a good paraglider pilot you already have the prerequisite skill to fly paramotor. The only thing you’re missing is ground school in air law and weather. And in some countries (not the US) you are required to have license and registration. Sounds funny but is true.


Top 50 recent answers are included