Personally I think I would rather to take my chances with the pump pressures being close enough to maintain an acceptable imbalance, rather than me not cocking up the crossfeed in the heat of the moment. The answer I was given was that the check valves in the tanks may have slightly different pressures so an unintentional and hence unnoticed imbalance could occur. When I did my 737 conversion, after flying many aircraft with more complicated fuel systems and crossfeed methods, I questioned this technique and asked why not just leave all pumps on and have the crossfeed open to allow the engine to draw fuel equally from both tanks. Not easy while managing the whole engine out problem. The aim of the game is not to exceed 453kgs and to try and judge it so that you land with a zero imbalance. You then crossfeed to imbalance up to 453kgs the other way and so on. Our company policy (UK 737 classic operator) is to have the crossfeed closed during asymmetric flight and allow an imbalance to occur up to but not exceeding 453kgs.
It seems to me that in attending to a supposed problem of possible fuel pump unequal pressure output, there is a far greater danger of inadvertent significant fuel imbalance than there was with the "old" method of simply opening the cross-feed valve immediately after engine close down and leaving all wing tank fuel pumps on.Īnyone struck this situation during one-engine inop flying in the simulator? ie forgetting to continually switch fuel pumps on and off as part of cross-feeding policy? In fact, often the fuel imbalance becomes reversed because the crew are too busy coping with the one engine inoperative game plan. Now what I see in the simulator, is after engine failure at V1, the crew stuffing around with fuel pumps and cross-feed and often forgetting to monitor the cross-feeding with two pumps off. With the old system of cross-feed valve immediately opened a few seconds after simulated engine failure, we never experienced fuel imbalance on one engine inop.
#How to crossfeed engine failure simulator
Is that a correct assumption?īefore my old company arranged simulator re-current training, we practiced simulated engine failures in the real aircraft by throttling to idle at V1 or just after, then flogged around the circuit or instrument approaches. I understand that the "old" procedure lost favour due possible differing fuel pump output could white-ant attempts to keep fuel balanced. Repeat ad nauseum until safely on the ground. Then, after it reaches the maximum im-balanced permitted, you open cross-feed and switch off the fuel pumps of low contents side until fuel balanced, then back to normal feed until the imbalance again rears its ugly head. I understand that this policy is no longer valid and that Boeing (?) require that following (say) engine failure at V1 you have to wait for the imbalance to occur.
#How to crossfeed engine failure full
This saved fuel imbalance problems at a time when hands were full coping with one-engine inoperative and sorting out where to go navigation-wise. In fact with engine failure above V1, the PNF got the APU on line and cross-feed valve open within a few seconds of engine failure. When I did my B737-200 rating under a Boeing instructor 24 years ago, part of the engine failure and shut down drill was cross-feed valve open.
0 kommentar(er)
