View Full Version : 787 CAC Surges - did we do the right thing?
I had my third CAC shutdown in three years yesterday. Our flight crew operating manual is like the ladybird book of aircraft systems and provides almost no information....I had to find out that we had pressure and flow sensors around the CAC from the MEL! Unfortunately the other CAC on that side was an MEL item so we had all our air coming through one pack. The system seemed stressed by this and the pressurisation surges of over 1000 feet per min could be felt on the ears. We dumped 40 tonnes of fuel and diverted. Do you guys agree with my decision as I was not happy going across the Ocean relying on one pack.
yotty
12th Jan 2018, 11:00
Perhaps follow the QRH and contact Maintrol?
LME (GOD)
19th Jan 2018, 15:30
if you're single pack, you become non-etops and possibly altitude restricted. Both these will require additional fuel. The MEL restriction for single pack normally has a requirement that the remaining pack is fully operation (no deferred items).
Yottabyte - Completed the QRH .....its first “condition note” is pressurisation behaves normally at low altitude (which it didnt) then contacted maintrol who agreed with the decision to divert.
What I was trying to ask was what you felt were the risks associated with putting the entire air con demand on one pack ( which appeared to be struggling). I notice on the maintenance page “CAC Surge margin” and CAC Inlet / outlet pressure. Didn’t know these existed during the flight (if I had looked at them I guess I would have seen higher figures than normal)?