外部案例
2023年3月8日一架注册为C-FHCM的Westjet波音737-8 MAX从纽约肯尼迪机场（美国）飞往加拿大卡尔加里的WS-1681航班，载有165名乘客和6名机组人员，在起飞转弯过程中，机组人员听到前起落架发出异响，在离开了肯尼迪机场04L跑道。在离地收起落架后，前起落架指示异常，机组在7000英尺按检查单处置后，解决了这个问题，继续飞往卡尔加里。Westjet Dispatch在预计着陆前约一小时通知卡尔加里机场前起落架问题。在向卡尔加里降落时，机组人员宣布PAN PAN，并告知他们计划在跑道上停车，需要被拖到停机坪。这架飞机安全降落在卡尔加里的17L跑道上，并能够依靠自己的动力滑行到停机坪。
加拿大TSB报道称，“前起落架压力密封件在起飞滚转过程中发生故障。油舱内的压力损失使支柱受到压缩，无法在收入起落架舱之前定中。密封件被更换，SDR被提交给加拿大运输部。飞机被放行继续投入运营。”
经了解机组在收起落架时出现红灯亮，地面检查时发现减震支柱漏油，无镜面。检查与门封严发生了剐蹭。AHM监控到AIR/GND SYS信息，并有32-01102 “PSEU NOSE GEAR ON GROUND PROXIMITY SENSOR IS TARGET NEAR IN AIR”代码。更换了动静封严和受损的门封严。
点评：故障表象与冬季前起镜面到底的经验类似，有开发监控。
A Westjet Boeing 737-8 MAX, registration C-FHCM performing flight WS-1681 from New York JFK,NY (USA) to Calgary,AB (Canada) with 165 passengers and 6 crew, departed JFK’s runway 04L when during the takeoff roll the crew heard unusual noises from the nose gear. After becoming airborne and selecting the gear up an abnormal indication for the nose gear followed prompting the crew to level off at 7000 feet while troubleshooting the issue. The crew was able to resolve the indication and continued the flight to Calgary. Westjet Dispatch informed Calgary Airport about the nose gear issue about one hour prior to estimated landing. Descending towards Calgary the crew declared PAN PAN and advised they were planning to stop on the runway and needed to be towed to the apron. The aircraft landed safely on Calgary’s runway 17L and was able to taxi to the apron on its own power.
The Canadian TSB reported, that “the nose landing gear pressure seals failed during the takeoff roll. Loss of pressure in the oleo kept the strut compressed and unable to center before retracting into the gear well. The seals were replaced and an SDR was submitted to Transport Canada. The aircraft was released for continued service.”
