View Full Version : 737NG engine quiz

24th Sep 2010, 03:42
can anybody tell me? above what number N1 OR N2 can a rolling engine suck the people in the hazard area into the engine.:confused:

24th Sep 2010, 09:31
Don't know, never tried it. :rolleyes:

I would guess ground idle would be sufficient when you make a dive for it? good luck on your attempt!:ouch:

24th Sep 2010, 10:55
This question cannot be answered easily as it all depends on the size of the engine. Imagine an idle engine of a B777 and beside it an idle engine of a Cessna Citation. The amount of air sucked through at idle decides about the hazard being present.
In both cases, stay away as far as you can, the invisible hazard is the most dangerous one.

24th Sep 2010, 11:21
Errrr...that's why he said "737NG engine quiz"...

you know...the standard CFM56-7B24..or 26..or 27..or 27A 737 engine.

24th Sep 2010, 16:55
B744 - at idle. I don't know how much detail you seek, but pages 6 and 7 here may help? http://www.tc.faa.gov/its/worldpac/techrpt/ar03-32.pdf

26th Sep 2010, 01:38
Idle if within a few metres of the intake.
Obviously worse if wearing loose floppy clothes that may pull you in first.
Classics had an ingestion hazard line marked on the fuselage.
Every engineering workshop I have worked in has hazard area charts on the walls.

26th Sep 2010, 15:06
thanks everybody .
i know the question is kinda weird .seems has nothing to do with our flight .
but the other day i saw this procedure on a website about 737 operation ,during the engine shut down ,it says :turn off the beacon when the N2 drops below 20.and i do not know where is this from and if any airline follow this rule.cuz my company doesn't .and there is this another picture .when we arrive at the gate .the captain cut off the engines and the first officer turn off the beacon which give the ground mechanic the signal the engines are shut down now and he can come over to put the chocks in .
so bring this two piecese info together comes this question .
any 737NG pilots here with cmf56-7 engine ?plz tell me what u do during the shutdown flow .

26th Sep 2010, 15:08
N1<5%. That is the bit that 'sucks'

de facto
26th Sep 2010, 15:16
The ground personnel(mechanics) will approach the aircraft when the beacon is switched off from the rear of the engine.(away from the engine intake hazard zone).
By the time they get there the engines will have spooled down even more, if not to zero.

Follow your SOP:ok:

26th Sep 2010, 16:11
The ground personnel(mechanics) will approach the aircraft when the beacon is switched off from the rear of the engine. -in your dreams! I've seen them at the fwd hold (737) just as the beacon went off at fuel off (this was in a company that did not use 5%)

26th Sep 2010, 17:19
Some handling personnell only wait for the beacon light to come off and make a run for it... the smarter guys wait a couple of seconds before approaching the hazardous area's.

I personally wait a bit with switching off the anti coll light until N1 < 10% or so. It's not written in any SOP, learned it from an instructor and I now use it as a GOP (General Operating Procedure), or some might call it 'airmanship'.
(Another example of GOP is retrimming to about 6-5 units during taxi in, while the flaps are travelling up)

27th Sep 2010, 00:07
Sounds like you need to figure this one out for yourself...