Tailpipe Fire Sign??

[spannersatcx]

Starter duty cycle is not applicable when putting out a jet pipe fire. It's cheaper to replace a knackered starter than a burning engine and wing.

[Old Smokey]

Maybe a bit off topic, or at least the flow of it, but one of the niceties of the Ground Manoeuvering cameras on the B777-300 is the availability of a 'live' TV viewing of the rear of the engine during start. T'is definately a part of my scan during engine start.

A picture is worth a thousand words, or a thousand gesticulations from the ground engineer.


Regards,


Old Smokey

[777fly]

Maybe you guys flying the small stuff are still using hand signals, but all heavy jets start in communication with an engineer/ operative on the ground intercom.One company I worked for did not allow starts on hand signals only and had a call ' flames in No... engine' from the ground crew to alert the flight crew to a jetpipe fire.This is an non-hazardous event if it is dealt with correctly: fuel off, continue to motor the engine until the flames go,starter off. If it is left to burn ( incorrect drill or no way to motor the engine) there is a threat to the engine/aircraft structure.The EGT sensors, readable in the cockpit, are at the rear of the turbine stages of the engine and only sense the peak gas temperature within the engine. There are no sensors in the engine exhaust duct and the flight crew have no indication whatsoever of a jet/tailpipe fire- any warning will come from ground crew or ATC observing the event. I once had an engine go sub-idle taxiing in which caused a jetpipe fire. It was ATC who saw it first.

[lomapaseo]

777Fly

Right on.

We need as many pilots as possible like yourself.

[Dan Winterland]

In the early 80's, flying training in Jet Provosts, jet pipe fires weren't unusual due to the aircraft having an engine in the middle and a long tailpipe to fet the hot gas out the back. The engineers were required to check the jet pipe after shutdown. One day the didn't and after the last flight of the day they towed one into the hangar with a tailpipe fire still burning!

The definition of chaos was quite clear that day!

[Charles Darwin]

Originally Posted by HotDog

The Proteus MK705 on the Britannia 100 was prone to torching from the tail pipe on start up. Quite spectacular, especially at night.

So did the old Fokker F-27, especially during battery start. Flames up to 2 meters long. And, oh yes, lit up the night!

[spannersatcx]

There are no sensors in the engine exhaust duct

yes there are, EGT thermocouples

and the flight crew have no indication whatsoever of a jet/tailpipe fire

yes there is EGT will rise after engine is shut down.

Don't get confused with cold stream duct and turbine exhaust (which is where the burning fuel will be).

[777fly]

Ok, depends if we are talking TGT or EGT. Also upon the particular engine design as to where EGT sensors are. I accept that an EGT temp rise might be indicated after engine shutdown, but the thread started with a discussion of the starting case. If the engine has not lit properly and the unburned fuel is igniting in the exhaust duct, I would expect that any sensors would show a lower than normal temperature, since any combustion in the engine is inefficient at that time. The motoring engine would also be blowing the heat out of the engine. I have operated many different engine types where the 'hot start' - an internal starting fault - is readily seen on the gauges , whereas a jetpipe fire is not.