123

The reason is the large spinning thing on the front. Residual fuel in the engine has been known to auto-ignite (i.e. combust without a spark), causing the prop to spin, causing serious injuries and deaths. A lean cutoff reduces the risk that someone handling the prop will get maimed or killed. In a car when you turn the engine off usually it is in park or ...


121

Several advantages: Wing structures are hollow and voluminous in order to provide structural rigidity against flutter and carry flight loads. This provides the space needed to store fuel. On a conventional aircraft, placing fuel tanks in the wings places the fuel mass very close to, or on, the center of lift. This dramatically reduces Cg shift during ...


89

It's for wing bending relief (for cantilevered wings). As the generated lift bends the wings upward, the weight of the fuel will counter that. As the plane loses weight in-flight due to burning fuel, so does the need for wing bending relief (less weight → less lift), that's why the wing tanks are the last to be used. For context, a Boeing 777-200ER can ...


81

I see what you're saying, but there's something you're overlooking in your logic. You're looking at an airplane sitting on the ground, where the wheels are near the fuselage and most of the wings are dead weight that creates strain on the structure. Think about one in flight. Now all the lift is coming from the wings, imagine the airplane suspended by ...


60

You can find the full incident report here and this topic is touched upon briefly, but in short they had little to no time to entertain any other options but a full speed landing. It was not until the aircraft [was] on the final descent for landing that the Commander realised they could not reduce the thrust on the number 1 engine. The speed was not ...


58

Engine #2 wasn't doing its job either Had the situation just been engine #1 stuck at high thrust, with engine 2 normally controllable, than what you describe would be a reasonable response to the situation. However, that was not the case with CX780 -- during approach, Engine #2 was stuck at 17% N1 (or rather below idle) and thus delivering effectively nil ...


57

A quote from the book of regulations, Chapter 14, part 23, verse 951(b): (b) Each fuel system must be arranged so that— (1) No fuel pump can draw fuel from more than one tank at a time; or (2) There are means to prevent introducing air into the system. On a high wing aircraft satisfying #2 on that list is pretty easy: If you connect both tanks to ...


55

In short, 40 kV isn't that much voltage for applications that are intentionally creating an electrical arc. Car spark plugs also use voltages in the tens of thousands of volts for the same reason, for example. As for why that is: In general, air acts as an electrical insulator. That is, electricity won't pass through air at normal voltages. Which is good ...


48

Having all the payload of a plane concentrated at the fuselage creates a large bending load on the wings in order to support that weight. Storing fuel in the wings allows some of that weight to be placed at the same place where it's being supported, in the wings. Distributing the weight into the wings reduces the loads where the wings meet the fuselage.


47

Maybe This is dependent on the air frame and varies from plane to plane and not all planes have capability of moving fuel although most large planes do. The Concorde moved fuel all over the place from its 13 tanks to cool the nose cone as well as trim the aircraft. It was perhaps one of the most complex implementations of such a system and kept the flight ...


38

Which fuel tanks are used in order of priority in aircraft? What you're talking about, in large aircraft, is often referred to as the fuel burn schedule. Light aircraft generally do not have a fuel burn schedule though they may have have minimal requirements. The fuel burn schedule is dictated by the aircraft design and is thus different for different ...


37

Combustion in a gasoline internal combustion engine for most aircraft, requires four things: fuel, oxygen, compression and ignition. If the engine is starved of fuel, accidental combustion (and an accidental spinning prop) will not happen. So shutting off the fuel is one way to prevent accidental "start" if even for one stroke. Oxygen is ubiquitous and ...


36

You're right. But it's not because of the slats. It's because of what the plane is doing when the slats are being used. The slat position is used in some system logic because it's indicative of a takeoff and approach. For example, on the MD-11 the engine ignition is automatically put into continuous mode when the slats are operated, because that's ...


35

The simple answer is weight/risk/added complexity: the systems are heavier than they are worth for the problems they avoid in aircraft. While ice blockage has been an issue for aircraft in the past, planes that fly high enough to warrant it have fuel heating systems to avoid this very issue. The reality is that the chances of water getting into marine fuel ...


35

That's nothing special. Car ignition coils also put out 40kV (try grabbing a spark plug wire on your car, that is leaking spark due to insulation breakdown, with your hand while it's running; FUN FUN FUN!). You need that voltage to jump an air gap reliably in a piston, or jet engine's, combustion chamber. That high a voltage allows fairly large air gaps ...


30

It's both a maintenance and safety feature. You need a way to cut off fuel flow to the engine compartment, either to work on the engine, or because of a fire at the engine, or because you are doing a forced landing and it helps reduce the risk of your entire fuel contents seeping onto your hot engine if you bend things a bit putting it down and a fuel line ...


28

Sheer volume is the reason. Aircraft use fuel at an astounding rate. A Panamax-class container ship is enormous - bigger than the USS Iowa or the Essex class aircraft carriers on display at many major port cities. They burn 9900 litres of fuel per hour. A 777 burns 7.5 tonnes of fuel per hour, or at 800 g/l for Jet A, that's 9375 litres of fuel per hour. ...


27

added weight increases the structural load applied to the wings different gravitational forces and wing-bending between full and empty tanks result in repeating stresses shortening the aircraft life-span As a result of the effects of lift (and the deceasing need for it as the plane lightens) the reverse is actually true see here higher risk of ...


26

I wrote an email to AirZeroG and asked them: Other than the interior, are your aircraft modified in any way to handle zero-g flight? Here is the response that they gave me: Dear Sir, Except free floating area cabin configuration, there are very few differences with a “standard aircraft”. The most significant one is installation of Zero-G meters ...


26

No it is not normal. It can happen if the wing tanks are fully filled, typically for long trips or when the airline is tankering fuel to airports where fuel is more expensive. When cold fuel warms up it expands. With full tanks, the fuel has to go somewhere and it flows through the vent channels and will end up in the surge / vent tanks in the wing tips. ...


26

The conversation may have been about fuel pumps or fuel transfer valves but the flight attendant was probably told that as a simple explanation - it would not have been the real cause. Aircraft have multiple systems to pump fuel, transfer, and pipe it so no single failure will affect normal operation. For example, pumps have automatic bypass valves so ...


26

The PA-28 Family of aircraft have two fuel pumps, an engine driven mechanical pump that is always pumping (so long as the crank shaft is spinning) and is considered the "main pump". The airframe also has an electrical backup pump that can be actuated by the pilot. The tanks do not have their own pumps. You should check the POH for your airframe but ...


25

Yes fuel is moved around, and balance is indeed an issue. The A330 has trim tanks in the horizontal stabiliser, and so does the A380. Fuel can be stored there to balance the aircraft - without trim tanks the stabiliser would be set to produce lift to balance the plane, and this causes extra drag. In the A380 fuel transfer occurs automatically, unless a ...


25

In 747-100/200 aircraft, takeoff was accomplished tank-to-engine (meaning each engine was fed from it's corresponding main tank). After takeoff the fuel burn schedule called for center tank fuel to be used after takeoff until exhausted. This was done by turning on jettison/override pumps in the center tanks that put fuel from the center tank into the common ...


23

First, to debunk a myth regarding the Hindenberg, which always gets brought up whenever hydrogen is mentioned. Hydrogen is less safe than liquid fuel, but it is not less safe than natural gas or propane. Hydrogen has a higher flame propagation velocity than hydrocarbon gasses, but contains much less energy per unit volume than hydrocarbon gasses. A huge ...


22

You should check your POH but it may just be that the instructor in question was recently flying a lot of Pipers and it was force of [bad] habit. This POH for the 172S is in agreement with you. BEFORE LANDING .... Fuel Selector Valve -- BOTH. You should consult the checklist in the POH that is with the airplane in question to be sure.


22

In gaseous form, the amount of -- the mass of -- hydrogen you could store in the volume of aircraft fuel tanks would be negligible. In order to store enough mass of hydrogen, you'd have to store it liquified, which is how it's stored in rockets. In order for that to be useful, though, you'd have to have engines entirely redesigned in order to burn cryogenic ...


22

From the incident report section 1.1.4: a. At 0519 hrs during the descent to a cleared level of FL230, ECAM messages “ENG 1 CTL SYS FAULT” and “ENG 2 STALL” were annunciated within a short period of time. According to the Commander, a light “pop” sound was heard and some “ozone” and “burning” smell was detected shortly before the ECAM message “ENG ...


21

The inerting system was added to the A320 as a result of a new FAA regulation in 2008: On 21 July 2008, FAA required operators and manufacturers to incorporate a Flammability Reduction Means (FRM) or Ignition Mitigation Means (IMM) on fuel tanks having a flammability exposure exceeding certain thresholds [...] (Airbus FAST Magazine 44) Airbus found that ...


20

FAA Advisory Circular AC 103-7, Paragraph 19 has this to say: MAXIMUM FUEL CAPACITY OF A POWERED ULTRALIGHT VEHICLE. The maximum fuel capacity for a powered ultralight vehicle is 5 U.S. gallons. Any powered ultralight with fuel tank(s) exceeding this capacity is ineligible for operation as an ultralight vehicle. a. Determination of ...


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