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I don't understand why they could not airstart the engines once they were at a lower altitude. Something is wrong here.

yes...

I'm not a pilot, but maybe (Maybe?) something burned out at that high altitude, or else the altitude caused some sort of other permanent damage?

Maybe they were that incompetent.

Two possible explanations is that they slowed below sufficient airspeed for an airstart or that for one reason or another they did not windmill the engine long enough before airstart to overcome rapid cooling brought on by the flameout at high altitude.

Either way, these were a couple of idiots who somehow thought getting an airplane to 41k was a manly feat.

To quote Paul Harvey, "Gonads are useful for their purpose but they are no substitute for brains."

I think these guys were falling like a rock. It would be interesting to know if they had a military background or not. I'm betting not.

The AV Web article indicated the plane had been serviced subsequent to a bleed air circuit indicator light illumination.

Bleed air is nothing more than air that has been compressed by one or more of the compressor stages of a turbine engine. Bleed air is hot, as a result of being compressed. The more compressor stages that have compressed the bleed air, the higher the temperature and pressure will be.

In most turbine powered aircraft, bleed air is used for pressurization, air conditioning, engine anti-ice, windshield anti-ice, de-ice boot inflation, to power a venturi system, (creates vacuum to control outflow valves and power gyroscopic instruments), and on some aircraft, to anti-ice the wing and tail. When bleed air is extracted from an engine, some power loss will result. When operating bleed air powered wing heat, engine, or windshield anti-ice systems, aircraft performance and engine power settings will change and some loss of performance will result.

There are bleed valves on some turbine engines that serve only to improve the engine's idle and acceleration characteristics. These valves operate pretty much automatically, and are of little concern to the pilot unless they malfunction. A malfunctioning bleed-air circuit can cause unstable idle RPM, or compressor stall.

In flight engine restart difficulties could be compounded by several factors, icing of the air-bleed circuitry, and operational paramaters of the engine. The latter may be a safeguard designed into the engine so that the blades don't overheat. Air is bleed off from the compressor, run it down the shaft, and blown through the middle of hollow turbine blades. If the air-bleed circuit is faulty (or obstructed), the compressor's rotation may be governor limited.

The first type of compressor stall, the less severe type of stall, is the "axis-symmetric stall", is a straightforward expulsion of air out the intake due to the compressor's inability to maintain pressure on the combustion chamber.

In the second, more-severe "rotational stall", the air flow disruption of the stall causes standing pockets of air to rotate within the compressor without moving along the axis. Without fresh air from the intake passing over the stalled compressor vanes they overheat, causing accelerated engine wear and possible damage.

The most likely cause of a compressor stall is a sudden change in the pressure differential between the intake and combustion chamber. Jet aircraft pilots must take this into account when dropping airspeed or increasing throttle.

Flying through a cloud of ice crystals at max altitude, or while attempting an in-flight engine restart (in conjunction with an existing air-bleed circuit malfunction) could result in some problems for pilots.

Proper fuel flow is very important in a gas turbine engine. Unlike an engine with a carburetor, the amount of air flowing into a jet engine is not regulated. Jet engines suck in whatever air is available. Engine power is controlled by the amount of fuel that enters the engine's combustion chamber. At sea level, only about 25% of the air entering the engine is burned. The other 75% just flows through the engine, absorbs heat and provides mass to be routed through the turbines. The proper fuel flow for a given engine RPM varies with altitude.

In general, the proper fuel flow for a given situation depends on the following:

Thrust lever position
Compressor discharge pressure (P3)
Engine inlet temperature (T2)
Engine RPM and engine acceleration

The above parameters are the data the fuel control uses to decide how much fuel is delivered to the combustion chamber. The amount of fuel the engine gets for a given set of circumstances is called the "Fuel Schedule". Engine starting phase has it's own fuel schedule. All this would be just a bit much for a pilot to consider while attempting to keep the airplane right side up. Abrupt thrust lever (throttle) changes or improper fuel flow might cause excessive engine temperatures, or even an engine flameout due to excessive or insufficient fuel flow. Engine starting would be much more a function of technique, thus more prone to pilot induced errors. And so fuel control is done with a hydro mechanical device that regulates the amount of fuel the engine receives and a fuel control computer.

The result of all this is that the pilot merely tells the fuel control unit how much thrust is desired by moving the thrust lever. The fuel control delivers the proper amount of fuel to the combustion chamber for optimum operation of the engine according to the parameters observed at the time. The point of all this: the air-bleed can become an extremely critical factor for proper engine operation at max altitude or during in-flight engine restarts and its failure may well be implicated in this crash.

I'm thinking they may have panicked and tried to start them too high and it didn't work. I assume that plane has an APU so running the battery down wouldn't be an issue???

I don't understand why they could not airstart the engines once they were at a lower altitude. Something is wrong here.

I'm with you. They go on about how the pilots were "goofing around", but taking a piece of equipment to the mfgr's reccomended limits hardly qualifies as reckless.

<< I don't understand why they could not airstart the engines once they were at a lower altitude. Something is wrong here. >>

Yep.

'Finger trouble' has raised its ugly head again.