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Starting first engine ... but APU dies !

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Starting first engine ... but APU dies !

Old 3rd May 2008, 17:37
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Starting first engine ... but APU dies !

Fuel is already ignited but N rotations are still low when APU auto shutdown ...
What's next ?
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Old 3rd May 2008, 17:42
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Engine master off quickly, call ground.
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Old 3rd May 2008, 17:49
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Usually,

Fuel >>cut off

Motoring engine when rpm adequate to blow out the remaining fuel...

Inspect all with maintenance afterwood...
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Old 3rd May 2008, 17:57
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depends how much you want to get home...continue start, monitor egt and rpm's for increase.
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Old 4th May 2008, 05:30
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In response to LME (Sub-God) from Zeus!!

Suggest continue with the start to see if engine starts WITHIN limits. If start OK, then continue with X-bleed. If not, then shut down & go to hotel! V. easy.
HA56
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Old 4th May 2008, 05:32
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LME,
Pls dont take me 2 seriously!!
HA56
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Old 4th May 2008, 15:46
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don't worry hardarse...i never take pilots seriously....a modern fadec engine should be able to cope if it makes it to light off.....it might just be slow to spool up to idle
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Old 4th May 2008, 16:24
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So, main risk is EGT rising over limit ... HOT START

If manual start, operator will have to cut off fuel before EGT red mark.
If automatic sequence, FADEC should do the same ...

Any chance of tail pipe fire ... ?
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Old 4th May 2008, 16:49
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Starting First Engine

Required action depends on Company SOPs and also dependant on how low are the N1,N2 and N3 readings. No specific numbers are available in any AMM but the start can be continued but being very very watchfull as long as the EGT readings do not overtake the N2 or N3 readings accordingly.(2 spool or 3 spool engine).
Chances of a Tailpipe fire are minimal if you cut off the fuel quickly enough.
As mentioned before FADEC equipped engines should handle the situation, but as with anything automated you still have to be aware.
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Old 4th May 2008, 17:24
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Knowing the self-sustaining speed of your engine can be quite useful, although as manufacturers are increasingly reluctant to provide any technical details to aircrew, these numbers might be difficult to come by.

Another thing to consider is that, unless the external power is still plugged in, only battery power will be available, which might lead to a limited number of engine instruments available to monitor the start.

Selecting fuel off will certainly prevent a hot-start, or any start for that matter.
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Old 4th May 2008, 18:02
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Thanks for your answers.
Another thing to consider is that, unless the external power is still plugged in, only battery power will be available, which might lead to a limited number of engine instruments available to monitor the start
Excellent point !
Electrical power transfer + System Display logic might, for a few seconds, withdraw from view the critical EGT reading.
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Old 4th May 2008, 18:21
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Cool

Motoring engine when rpm adequate to blow out the remaining fuel...
If you've lost the APU then there is no air to motor the engine!
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Old 4th May 2008, 21:43
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Any problem to restart the apu ???
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Old 4th May 2008, 23:39
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Not in time to continue motoring.
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Old 5th May 2008, 15:04
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Had a similar problem before on the A340-600.
APU was U/S and so we used on ground power units and an air cart.
We start engine 2 first, then engine 1, pushback, set park brake cross bleed start 3 and 4.

This was the plan, however, we instructed the engineer to give air and opened the start master, when the ground power failed completely after the fuel went in. We lose all displays, bells and whistles going off. I continued the start by holding down the ENG key on the ECAM display and continued the starts on battery, and started engine two as well. Not a big deal, but it could go pear shaped quickly.

There are complications in only starting one engine on an A340 (not all busses are supplied) so you have faults ENG1 EPR mode and other ENG 1 minor faults.

The point is, we had a ground power during the start process and managed to continue on battery by holding down a key for the engine page to monitor and it all turned out OK.
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Old 5th May 2008, 15:30
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Our Ops Manual for A319/320/321 is supposedly pretty similar to Airbus SOPs from FCOM 3, and includes this line during the engine start bit:

In case the electrical power supply is interrupted during the start sequence (indicated by the loss of ECAM DUs) abort the start by switching OFF the MASTER switch. Then perform a 30-second dry crank.
Doesn't seem to allow for the 'suck-it-and-see' kind of discretion considered on some types during this discussion.
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Old 5th May 2008, 18:10
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I would suggest..cancel the start and have a long slow think. After almost 17000 hours of flying I have always found this works best.
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Old 6th May 2008, 03:16
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CONF,

Sounds like you're in the B737. Common to happen as the combination of weak APU,electrical load shed not chopping off the non essentials quick enough and etc. What I used to do was to turn OFF the galley power on pushing back.I am with an Asian carrier that serve hot meal on a 1hr 20min leg.Crew were time pressed to heat meals.

If this senario happen,reach for the STBY PWR tranfer switch to ON,if N2 below 40%,it is unlikely to start.Cut the fuel quickly, if there is a hung start,flame might come out from the front and back of the engine burning up the wing tank and you have no means to motor the engine or blow the flame out.Sitting duck basically. It would be more scary at night since you would only have evac lights in the cabin.
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