PPRuNe Forums - B744 Engine run up

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Quote:

According to my notes, it's not active below 70kts CAS.

I'm not intimately familiar with the TCMA logic on the GE90-115B, but I don't think that's the case. I am intimately familiar with the TCMA logic on the 747-8/GEnx-2B (which borrowed heavily from the GE90) and there is no airspeed inhibit - only air/ground (granted, relatively elaborate air/ground logic with the default state being air).

Quote:

Might be a good idea to buckle up for engine runs.

At least back when I was observing engine runs, we had more people on the flight deck than there were seats, sometimes a lot more.
I was responsible for the engine running functional test 20+ years ago when we did the first 777. When we did the very first engine run, I counted an even dozen people crammed into the flight deck :eek:. I was stuffed back into a corner, trying to take notes on how I could improve the test. The ECS system wasn't working right, and it was seriously cold on the flight deck. I was crammed next to one of the ECS outlets, and at one point there was snow coming out the outlet - I quickly exclaimed "no wonder I'm cold, it's snowing in here" :E. The mechanic in the right hand seat messed with the ECS controls and the snow stopped.
The next day I was at my desk updating the engine run functional based on what I'd observed, when I got a call from a guy in ECS.
"Are you the person who said you saw snow during yesterdays engine runs?"
"Yes.."
"That's not possible, what did you actually see"
"Well, I observed white particulate matter coming out of the ECS outlet. It floated down and landed on my note pad, where it turned to water".
"Oh..." <click>
:rolleyes:

Quote:

Originally Posted by NSEU (Post 9507229)

We had an outboard engine stall on a 744 high power engine run and the aircraft reportedly moved six feet sideways, althought it could have been the same as in your case. Might be a good idea to buckle up for engine runs.

According to my notes, it's not active below 70kts CAS.

Standard procedure for our EGR's is to buckle up at all times, and only those required for the EGR on the flt deck!

Quote:

Originally Posted by tdracer

at one point there was snow coming out the outlet - I quickly exclaimed "no wonder I'm cold, it's snowing in here" .

Our 744's used to spit small chunks of ice out of the ceiling vents on the Upper Deck on humid days. They were large enough to generate rattling sounds in the ducts.

NSEA - apples and grapefruit...
TAC (Thrust Asymmetry Compensation) and TCMA (Thrust Control Malfunction Accommodation) are completely different systems.
TAC is a flight control based system that moves the rudder to compensate for an uncommanded thrust asymmetry - such as an engine failure.
TCMA is resident in the FADEC and shuts down an engine that is at uncommanded high thrust and is not reacting to throttle movement.

Thanks, tdracer. Original message modified.