在高原启动阶段高振动为什么机组观察不到的问题，和波音做了沟通。
1、对于风扇和LPT振动，当N1 > 20%时；或者对于HPC和HPT振动（以先发生的情况为准），当N2 > 40%时，，AVM信号调理器将处理发动机振动指示。N1 < 20%或N2 < 40%阶段，VIB指示器将在AVM信号调理器通电时显示0.0。
2、在AVM故障情况下，VIB指示将为空白。
3、当N1 > 20%或N2 > 40%（以先发生的情况为准）时，VIB指示器上的DEU将显示FAN、LPT、HPC和HPT振动中的最高值。
4、在发动机启动阶段没有数据抑制逻辑。由于硬件和软件限制，发动机振动无法在N1 < 20%和N2 < 40%时被处理。
5、波音建议查阅附在此处供您方便参考的编号为737-13的飞行操作审查（FOR）文件“发动机振动程序”。FOR文件可通过MyBoeingFleet门户网站 -> 飞行操作 -> 公告和通讯 -> 737 -> 飞行操作审查访问。“对于具有AVM程序的飞机，在起飞功率设置、功率变化期间或直到发动机热稳定化之后，飞行机组应被告知AVM指示无效。”
No, the AVM Signal Conditioner will process the engine vibration indication when N1 > 20% for FAN and LPT vibrations OR N2 > 40% for HPC and HPT vibrations (whichever occurs first). The VIB indicator will display 0.0 starting when the AVM Signal Conditioner is powered up until N1 < 20% OR N2 < 40%. In case an AVM failure, the VIB indication will be blank. The highest of the FAN, LPT, HPC and HPT vibrations is displayed on the VIB indicator of the Display Electronic Units (DEUs) when N1 > 20% OR N2 > 40% (whichever occurs first). No, there is no data suppression logic during an engine start phase. Due to hardware and software limitations and as explained in R1), the engine vibration is not able to be processed below 20% N1 and 40% N2.
Boeing recommends to review the Flight Operations Review (FOR) 737-13 titled “Engine Vibration Procedures” attached here for your convenience. FOR is accessible via MyBoeingFleet portal -> Flight Operations -> Bulletins and Newsletters -> 737 -> Flight Operations Review. “On airplanes with AVM procedures, flight crews should also be made aware that AVM indications are not valid while at takeoff power settings, during power changes, or until after engine thermal stabilization.”
