View Full Version : Motoring After Deicing
A few days ago our ground engineer suggested on the intercom to do a motoring (let the engine run for a while) before placing the start levers to idle (i.e. before ignition), after deicing was complete.
I must admit I had never thought of that.
Bleed valves were already off, and I would have waited one minute after eng start to turn them on, but motoring the engine before opening the fuel was new to me...
Does it make sense to you?
Any residual glycol would be cleared anyway before opening the bleeds, but maybe it's a good idea to avoid burning the glycol inside the combustion chamber?
Old Smokey
7th Mar 2005, 13:39
Not a bad idea if fluid has been applied within the engine intake. Some people that I know delay 'fuel on' as a precaution against any excess de-iceing fluid there, definately non-SOP.
Maybe the ground engineer knew that the de-iceing crew had been over zealous in applying fluid in the engine area.
Regards,
Old Smokey
safetypee
7th Mar 2005, 17:52
It’s a good suggestion if De / Anti icing fluid inadvertently entered the engine or APU intake. However, the objective of the spraying team is not to spray fluid in these areas due to the problems of subsequent ingestion into the Air Cond. Problems arise when fluid is trapped in the bleed intakes and does not get blown though, which often happens with an APU.
Those who carry out motoring operations should be aware of engine starter limits; runtime duration and number of cycles. Some starters have a limit of 30 sec / three cycles per hour. Thus with one motoring cycle and a failed start and you are on your last attempt for some time before you can hope to dispatch.
Flight Detent
8th Mar 2005, 01:52
Hi all,
I operated the Classic B747 for AAI in some very cold parts of the world since '98, but have not flown with them for about 2 years now, and always recommended that the engine be motored for about 90 seconds on the starter prior to start lever.
It's a good idea that works well, limits the amount of 'bad egg' smells inside, after engine start and packs on.
Been doin' it for years.
FD
:hmm: