100% pure jetA emitted from 727 engines while being worked on/checked by mechanics.

[flynverted]

I was at work Fri. night, and while waiting at a gate with my crew for an arrival, maintenance showed up at a 727-200 parked at an adjacent gate. After several minutes, jet A started spewing from the exhaust from #1 engine. It was like jet exhaust, but the engine wasn't "lit". The fan blades were spinning as if the enging was running, but there was no "roar' of a running jet engine.
The jet A (from #1 engine) was just like jet exhaust; it was in mist form for approx. 50 feet or so from the engine, then it started to dissipate. This lasted for approx. 10-15 seconds. Then after a few minutes, the same thing with engine #2 for 10-15 seconds, then again with engine #3.

I've worked in the aviation industry for nearly 10 yrs. as a fueler, bag tosser, and load planner, and I have never seen anything like this. What could the mechanics possibly been checking/testing for this to occur?

TIA
flynverted

[fruitloop]

Are you sure it was fuel and not water,after a wash ???

[flynverted]

It was jet A. I was a fueler for 4 yrs. We were downwind, and were covered with it.

[HotDog]

A wet cycle; spinning the engine with fuel lever to start but ignition circuit breakers pulled.

[flynverted]

Thanks, HotDog!! That makes sense, but why? What were they looking for/checking?

[HotDog]

Usually for leaks after maybe a check requiring a fuel filter change or any maintenace on the engine fuel system.

[flynverted]

Thank you, HotDog, for taking the time to answer my questions.
Have a good day, mate.:ok:

[HotDog]

No worries pal.:ok:

[avioniker]

It's called a "wet motor" and done to purge any preservatives or oil from the engine before the first start after a check or a new engine is installed. It may also be done to confirm fuel pump or fuel control operation after maintenance and as stated above on rare occasions during a leak check.

[eng1170]

We also do what we call "dry cycle", where the engine is motored over on the starter with no fuel or ignition, again this is usually for leak checking engine components e.g hyd pumps. The starter does have a duty cycle that limits the time this can be carried out for. Also do ignitor plug checks where ignition only selected to audibly check for the "crack" as the plug sparks.

:cool: