2023年5月,1387飞机在恢复运行后,双发EEC报文时间显示故障,导致厂家每日监控报文被最后一个航段内容覆盖。
由于LEAP-1B发动机的世界机队典型故障NSV(高压转子非同步振动)以及PSS结冰这两个故障目前仅能通过EEC报文进行监控(见下图红框),NSV故障已在世界机队造成多起SE事件,而PSS结冰则会导致LOTC(推力失控), 这两类故障目前均有AD和多个SB关联,因此对EEC报文的持续监控非常重要。被迫采用人工修改时间后上传的方式,提供给GE。
为此做了相当多的隔离工作。由于其他报文,包括自主监控项目,在时间上都没有问题,非常罕见,也与波音和GE做了长时间的沟通。包括读取ARINC特定位置的值等。
但在别的飞机读取的时候(如下),两部DPC 标签150、二进制第11个字节(从右往左数第3位的)的状态,此位置都是1,而1387的为0。
波音给了相关检查建议。
/A11/ Obtain a reading of ARINC 429 data for DPC1(2) and MMR1(2) Label 150, Bit 11 per Ref /C/ AMM Task 31-31-22-970-802.
For DPC1, enter: 016/150/00/B
For DPC2, enter: 017/150/00/B
For MMR1, enter: 052/150/00/B
For MMR2, enter: 053/150/00/B
Record the value (0 or 1) of the third bit from the right and provide a picture/video of the MCDU screen findings.
Please note, this reading must be performed in an area where there is GPS connection. GPS connection may be verified by checking the Pos Ref page for location.
/A12/ Check the Captain and First Officer’s clock on the forward displays, record whether or not a “z” appears to the right of the time displayed, and provide a picture of the Captain and First Officer’s clock.
/A13/ Manually enter the time using the Airplane Configuration Data Maintenance Page. Observe if the “z” appears or disappears. Provide a picture/video of the Captain and First Officer’s clock and the MCDU screen findings.
/A14/ Remove and replace MMR1 and MMR2, please see AMM Task 34-31-42-000-801 “Multi-Mode Receiver – Removal” and AMM Task 34-31-42-400-801 “Multi-Mode Receiver – Installation.”
/A15/ Obtain another reading of ARINC 429 data for DPC1(2) and MMR1(2) Label 150, Bit 11 per Ref /C/ AMM Task 31-31-22-970-802.
For DPC1, enter: 016/150/00/B
For DPC2, enter: 017/150/00/B
For MMR1, enter: 052/150/00/B
For MMR2, enter: 053/150/00/B
Record the value (0 or 1) of the third bit from the right and provide a picture/video of the MCDU screen findings.
Please note, this reading must be performed in an area where there is GPS connection. GPS connection may be verified by checking the Pos Ref page for location.
检查结果看。
第一步,从右数第三位
For DPC1, enter: 016/150/00/B 读数为0
For DPC2, enter: 017/150/00/B 读数为0
For MMR1, enter: 052/150/00/B 不显示
For MMR2, enter: 053/150/00/B 不显示
第二步,最开始上机检查时机长和副驾UTC时间后面没有“z”,执行完第一步后有“z”
第三步,无法手动输入时间,只能手动输入日期,手动输入日期后“z”没有消失
第四步,再次记录从右数第三位
For DPC1, enter: 016/150/00/B 读数为0
For DPC2, enter: 017/150/00/B 读数为0
For MMR1, enter: 052/150/00/B 不显示
For MMR2, enter: 053/150/00/B 不显示
后对传DPC无效
对传MMR后,故障转移 。