Pilot should be able to communicate even if engine is on fire (especially then). Transponder doesn't suddenly stop working if your engine erupts in flames.
This is the key point, in the case that there is a fire on board (one of the likely possibilities with MH370) you want to be able to disable the offending circuit immediately. If that happened to be your transponder, so be it...the transponder really adds no value to the plane in terms of its ability to stay in the air, so disabling it and extinguishing the fire is the key priority over giving ATC the ability to identify you on radar via the transponder.
How can you ensure that the fire detection circuitry isn't ever mis-wired in the field (such that when engine 1 catches fire that the computer knows that it's engine 1 and not engine 2)? If that happens (and it's certainly the case that engine indicators have been crossed before in the field), the pilot now couldn't shut down the engine with the fire (theorizing that the computer wouldn't allow the discharge of fire bottles and cutoff of fuel to the only engine NOT displaying a fire alarm).
Or an engine that's streaming fuel (but not burning). Mid-ocean, you might want to cut the fuel to ensure you make landfall.
Substitute other failure scenarios as you need, realizing that any system has cases where the pax die when an alternate system would have saved them, but also vice versa.
It's not that we can't get systems that are right way more often than they're wrong, but that's still a long way to go from there to taking control from the pilot(s), IMO.
A determined suicidal pilot can find a way. If they can't, then they don't even need to be on the airplane right?
Disclaimer: I'm a [small airplane] pilot and well aware that I'm more likely to cause a crash from my own doing than from poor maintenance, but I definitely subscribe to the Boeing philosophy more than the Airbus...
As long as you trust the pilot with absolute authority over which equipment is running, this isn't going to happen. If something can catch fire (as in, any electronics?), it needs to have some kind of local breaker that the flight crew can switch off. The only trusted equipment there is one doing passive recording of some elements (the flight recorder).
Is there any legitimate reason for the pilot to disable the transponder? It seems like they should make it more difficult than just throwing a breaker in the cockpit.
I’ll keep this mind the next time I’m stuck on a burning rooftop and trying to communicate with the rescue chopper. I only hope the pilot understands Semaphore!
All systems on board an aircraft can be shut off for a number of reasons. In case of a power failure, the pilot must choose what functions are the most essential to the continued operation of the aircraft on the limited battery power remaining. A transponder may then become nonessential. Similarly, if it is faulty and is the cause of an electrical fire, power to the transponder must be able to be shut off.
Something physically attached (especially to the electrical system) can always theoretically interfere with the rest of the plane. If there is a fire, is the pilot just supposed to shrug as the plane goes up because he cannot interfere with the black box?
To me this looks like it's based on the principle that the pilot is always in control of the aircraft as much as possible, to allow recovering from unusual failures.
Just as communications equipment can be turned off if they pose a fire risk, it should be possible to vent the plane (after descending to a breathable altitude) if the system fails and the cabin begins to overpressurise. It's probably worse than depressurising since it could the plane to explode...
I don't know where you got your ATP from, but there isn't a good reason, in clear weather, to climb above the service ceiling for your air-plane.
Now, I don't miss-underestimate how failures happen, how they combine, but I know my procedures. If I'm pulling fuses for things, I'm going to first SQUARK 7700, have the co-pilot screaming on 121.5, whilst he is charged with flying the plane (following a heading, not dropping out of the sky, like AF447!) whilst I then follow the procedures for the kind of electrical fire. Even if it's only for 10 seconds, the 7700 will be picked up, the ATC will see it light up like an angry chirstmas tree. It will not be 'cancelled' by the transponder then being switched off, the operative would have to cancel it, which they wouldn't do until after contact had been reached. In the case of say 7500, they wouldn't take radio as reason to cancel it.
The point is, the transponder just happened to turn off at the perfect moment (between two ATC services) after the ACARS had been switched off long before.
If you had a fire, that had endangered physically separated, redundant systems in that manner, I doubt the plane would be able to fly for 7 hours. The 777 is a fly by wire plane.
However, if you wanted to drop off, un-noticed, it is the perfect time.
Occam's razor n all that. If I thought such failures were possible, as I've said before, I'd shred my pilots license tomorrow.
the display would also need to show what's getting sent to other aircraft, because that's useful situational awareness for the pilots that would be lost if the messages were directed. accidents have been avoided by pilots noticing conflicting instructions being given by ATC
Maybe, but having an electronic system on an airliner that can't be disabled could potentially lead to a fire that can't be extinguished and that's why you can shut down every system as the pilot.
Fixed wing pilot here. Handheld radio checklist item before I head out for flight. Even though my plane has redundant comms. Comms don’t work in a failed power scenario!
> As I mentioned in my article on the British Midland crash, the most effective way to prevent this kind of accident is by fitting airplanes with an Engine Indicating and Crew Alerting System, known as EICAS, or similar equipment. These systems automatically monitor engine performance and, should an engine fail, will produce a message informing the pilots which engine is the cause of the problem, dramatically reducing the probability of an incorrect identification. However, retrofitting the systems onto older 737s, which are most at risk, is not required and may be impractical or impossible.
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