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).
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
. 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"
. 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>
