787 "stAb greenband" EICAS
Thread Starter
Join Date: Apr 2003
Location: Sutton
Posts: 564
Likes: 0
Received 0 Likes
on
0 Posts
787 "stAb greenband" EICAS
QRH says "objective : to verify the stabilizer greenband and airplane loading are correct"
Anyone able to establish what difference in load will trigger this warning. Had it today for the first time (brought on by a tug with kangaroo petrol)?
Anyone able to establish what difference in load will trigger this warning. Had it today for the first time (brought on by a tug with kangaroo petrol)?
This is from my FCOM:
"The stabilizer green band monitor is part of the crew alerting function and helps confirm that the green band displayed on the stabilizer position indicator is correct for the actual takeoff weight and CG. based on the gross weight and CG entries in the FMC. Two nose gear pressure transducers provide actual airplane gross weight and CG information. The nose gear pressure data is used to determine two separate sets of validation limits (one for each transducer). The FMC calculated stabilizer green band is then compared to the validation limits from the transducers. The EICAS advisory message STAB GREENBAND is displayed if:
computed green band disagrees with pressure transducer data; or
the two transducer values are not within the set tolerance; or
either transducer has failed"
So, we are not told what the actual figures are that will trigger the message. Maybe the maintenance manual has the answer?
"The stabilizer green band monitor is part of the crew alerting function and helps confirm that the green band displayed on the stabilizer position indicator is correct for the actual takeoff weight and CG. based on the gross weight and CG entries in the FMC. Two nose gear pressure transducers provide actual airplane gross weight and CG information. The nose gear pressure data is used to determine two separate sets of validation limits (one for each transducer). The FMC calculated stabilizer green band is then compared to the validation limits from the transducers. The EICAS advisory message STAB GREENBAND is displayed if:
computed green band disagrees with pressure transducer data; or
the two transducer values are not within the set tolerance; or
either transducer has failed"
So, we are not told what the actual figures are that will trigger the message. Maybe the maintenance manual has the answer?
There was a similar problem on the 777 I think. Sometimes the oleo would 'stick' after a bounce by the tug or after loading. As a consequence the oleo pressure didn't compute with the required C of G and the message would be triggered. The answer I think was to release brakes and tow the aircraft slowly to 'settle' the oleo. It's been a while since i've seen it, I thought it had been fixed. The Dreamliner is, of course, a Nightmare!!
