之前的理解是降低推力是为了降低滑油需求，但并不能增加滑油压力。空客的解释说有两种可能的情况，一是滑油泄漏，油箱油面降低，进入油泵的空气增多，所以压力降低。降低推力可以降低油泵的吸力，从而增加油箱回油，减少油泵中的空气，从而增加滑油压力，同时降低漏油。二是油泵故障，这时降低推力就是降低滑油需求量。具体参考 TechRequest 原文：
Q: ENG 1(2) OIL PRESS LO (AMBER ALERT)
“Gradually reduce thrust on the affected engine, in order to increase the oil pressure until the ECAM alert disappear.”Why can reducing thrust increase the oil pressure? Or is it beacause the reduced thrust is compatible with the reduced oil pressure?
A:
Please first note that the OIL PRESS LO amber alert may result from either a leak in the oil system or a failure of the oil pump.
In the case of an oil leak, the oil pressure drop is likely due to a low oil level in the tank not sufficient to prevent air from reaching the oil pump. The action to retard the thrust will reduce the suction of the oil pump.
This will then result in the increase of the oil quantity in the tank and subsequently to the increase of the oil pressure from the pump.
Note that as the oil pump will slow down with the thrust reduction, it is expected that the oil leak will also be reduced by this action.
In the case of a failure of the oil pump, the pump is not able to deliver enough oil to the engine. The thrust reduction will have no impact on the operation of the pump but as the engine needs for oil will be reduced, it is expected that the oil pressure will increase.
Finally, please note that in both cases, if the oil pressure continues to decrease and the thrust reduction action remains not sufficient to recover the correct oil pressure, message ENG 1(2) OIL PRESS LO (RED ALERT) will request to shut the engine down.
