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一、防冰活门限流器堵塞
737NG飞机发动机防冰活门故障率一直都很高。
之前针对件号3215618-4的活门,由于环境污染的影响,限流器时间长了后会被堵塞,有定期更换送修进行清洁。
▲-4的活门
之后Honeywell 推出了-5的活门,将限流器改成了可拆卸在翼清洁的。
▲-5的活门
相关的手册程序在AMM TASK 30-21-11-100-801:Honest Orifice - Cleaning
此处堵塞,将影响防冰活门的压力调节功能,导致发动机高功率时,P5-11板上琥珀色的进气道防冰灯亮。
针对北方大气环境污染比较严重,定期清洁限流器可以有效防止由此导致的发动机防冰活门超压灯亮故障发生。
需要注意的是:安装限流器时要注意手册的力矩要求,不要拧的过紧,同时要涂抹防咬油。避免后续拆卸时将螺纹套拧出,只能更换活门。
波音也接到多家用户的报告,正在研究下一步改进方案。
二、防冰活门保留
如果航路无结冰条件,可按活门锁定在关闭位保留:
如果航路有结冰条件,需要按活门锁在打开位保留:
需要注意:M项里要求脱开的是防冰压力电门插头,不是防冰活门本体上的插头。
图中红框处DP1302压力电门插头
因为防冰活门锁定在开位后,失去了压力调节功能,会出现超压导致P5-11板琥珀色的进气道防冰灯亮和主警告灯亮,在起飞滑跑过程中,机组会滑回。
M项执行的其他问题:
1. 高压引气活门锁定螺钉断裂
由于防冰活门锁定在开位失去了调压功能,为了活门下游防冰管路压力和温度不超出设计要求;同时防冰活门一直处于打开位,发动机引气需求量加大,高压级活门可能会提前打开,导致引气温度高而跳开,所以M项同时需要将发动机高压引气活门锁定在关闭位。
锁定螺钉断裂
2. AMM DDPG手册防冰活门锁定螺钉力矩错误 TASK 30-00-00-040-803 MMEL 30-03 (DDPG) Preparation - Engine and Nose Cowl Anti-Ice Valves Inoperative 力矩是30 ±1磅寸
TASK 30-00-00-440-803 MMEL 30-03 (DDPG) Restoration - Engine and Nose Cowl Anti-Ice Valves Inoperative 力矩是20 ±1磅寸
之前我询问波音后的结果:
DESCRIPTION:
In AMM TASK 30-00-00-040-803,the torque of retaining screw on Engine Anti-Ice Valve is 30 ±1 in-lb (3.39 ±0.11 N·m).But in AMM TASK 30-00-00-440-803,the torque is 20 ±1 in-lb (2.26 ±0.11 N·m).
My question: Why are these two torque different? There is no torque for retaining screw on 9th stage valve,can Boeing add this torque to AMM? We often found the screw broken,especially on 9th stage valve during loosen the screw.I suggest boeing consider applying anti-seize agent when installing screws and and it into AMM.
RESPONSE: Boeing will revise the torque range for the retaining screw to 20 ±1 in-lb (2.26 ±0.11 N·m) in the 737 NG AMM TASK 30-00-00-040-803 in accordance with Honeywell CMM 30-20-05. Regarding the torque required for the 9th stage valve retaining screw, the Honeywell CMM 36-12-45 advises to install the screw until mated with slot in butterfly shaft. This information will be included in Task 30-00-00-040-803 and Task 30-00-00-440-803. The use of an anti-seize agent when installing the 9th stage valve retaining screw will also be included.
These changes will be scheduled for incorporation into the 15-Jun-2017 AMM revision.
大家在平时安装高压级引气活门锁定螺钉时,要涂抹防咬剂,并且注意别拧的太紧,到位了就行。
三、防冰活门安装
737NG-FTD-30-13001 EEC Overtemp due to Missing Nose Cowl Anti-Ice Valve Coupling
Loose anti-ice duct clamp
Extensive damage to ECU harnesses
注意安装卡子时转动卡子确保卡子已卡到位,利用APU引气测试防冰活门时注意检查渗漏。
防冰活门下面就是EEC,卡子漏气很容易造成EEC超温不工作,导致空停。
平时搜集到的一些问题的总结 也欢迎分享你的经验
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