印航423航班的最后31秒

印度民航部飞行事故调查局正式发布了6月12日印航423航班空难事故的第一版事故调查报告。

一般空难的第一版事故调查报告往往比较概略，很难有细节，但这次的报告却有非常多且重要的细节，悲剧的迷雾被驱散了很多，事故原因变得很具体了。

目前来看，飞机在起飞前一切正常，一切都发生在飞机离开地面后的

31秒里

世界协调时2025年6月12日8时7分33秒，飞机收到起飞许可。
8时7分37秒，飞机开始滑跑。
8分39秒，飞机离地。
8分42秒～43秒，飞机两台发动机的燃油开关被关闭，一名飞行员问“为什么关闭燃油开关？”另一名回应“我没有。”
8分47秒，两台发动机转速低至怠速以下，飞机最后的应急动力-空气冲压涡轮自动释放并工作。
8分52秒，一号发动机燃油开关被重新打开。
8分56秒，二号发动机燃油开关被重新打开。
两台发动机相继点火成功但无力逆转空速下降。
9分5秒，飞行员呼报mayday。
9分11秒，飞机坠毁。机上230名乘客中的229人，10名空乘，2名飞行员和地面19人丧命。

什么是发动机燃油开关？

顾名思义，它是控制油泵向发动机输送燃油的开关。在波音787上，两个开关并排，位于驾驶舱中部控制台油门杆的后方，是两个蘑菇头型的开关，向前推是开位，向后拨是闭位。

为了防止误操作，这两个开关都有限位装置，飞行员必须先向上提起蘑菇头，再前后拨动。

两个开关的距离大约是10厘米。此前也发生过飞行员袖口勾挂这个开关造成的误操作事件，所幸没有酿成事故。但是一秒之内两个开关相继被误操作，是什么情况下发生的？接下来还要更多的调查才能还原这两个开关被关闭的真相。

想看更多细节的朋友，我下面翻译了报告的事故回顾部分，大家可以参考一下。

Accident Flight

事故航班

On 12th June 2025, Air India’s B787-8 aircraft bearing registration VT-ANB arrived at Ahmedabad airport operating flight AI423 from Delhi. The aircraft touched down at 05:47 UTC (11:17 IST) and was parked at the bay 34.
2025年6月12日，印度航空一架注册号为VT-ANB的波音787-8飞机执飞AI423航班从德里飞抵艾哈迈达巴德机场。飞机于协调世界时（UTC）05:47（印度标准时间11:17）着陆，并停靠在34号停机位。

The crew of the previous flight (AI423) had made Pilot Defect Report (PDR) entry for status message “STAB POS XDCR” in the Tech Log. The troubleshooting was carried out as per FIM by Air India’s on duty AME, and the aircraft was released for flight at 06:40 UTC.
前一航班（AI423）的机组人员在技术日志中记录了飞行员故障报告（PDR），故障信息为“STAB POS XDCR”。印度航空当班维修工程师按照故障排除手册（FIM）进行了检修，飞机于06:40 UTC获准放行。

The aircraft was scheduled to operate flight AI171 from Ahmedabad to Gatwick with ETD 07:40 UTC (13:10 IST). The flight was to be operated by the flight crew comprising an ATPL holder PIC, a CPL holder Co-pilot along with ten cabin crew. Both pilots were based at Mumbai and had arrived at Ahmedabad on the previous day. They had adequate rest period prior to operating the said flight. The co-pilot was Pilot Flying (PF), and the PIC was Pilot Monitoring (PM) for the flight.
该飞机计划执行AI171航班，从艾哈迈达巴德飞往盖特威克，预定起飞时间为07:40 UTC（13:10 IST）。机组由一名持有航线运输飞行员执照（ATPL）的机长和一名持有商用飞行员执照（CPL）的副驾驶，以及10名客舱乘务组成。两名飞行员常驻孟买，前一天已抵达艾哈迈达巴德，并在起飞前获得了充分休息。此次飞行由副驾驶执行操纵任务（PF），机长负责监控（PM）。

The crew of flight AI171 arrived at the airport and underwent preflight Breath Analyzer test at 06:25 UTC and were found fit to operate the flight. The crew is seen arriving at the boarding gate in the CCTV recording at about 07:05 UTC (12:35 IST).
AI171航班的机组人员于06:25 UTC抵达机场，并接受了飞行前的酒精呼气测试，结果显示适合执飞任务。闭路电视录像显示，机组人员于约07:05 UTC（12:35 IST）抵达登机口。

There were 230 passengers on board, out of which 15 passengers were in business class and 215 passengers were in economy class including two infants.
机上共有230名乘客，其中15人在商务舱，215人在经济舱（含两名婴儿）。

Fuel on board was 54,200 Kgs and as per the load and trim sheet of the flight, the Take-off Weight was 2,13,401 Kgs (Max. allowed - 2,18,183 Kgs). The take-off weight was within allowable limits for the given conditions. There was no ‘Dangerous Goods’ on the aircraft.
机上燃油为54,200公斤，根据该航班的载重和配载单，起飞重量为213,401公斤（最大允许为218,183公斤），在当时条件下属正常范围。机上未装载危险品。

The calculated V speeds with available conditions at Take-Off were V₁ - 153 Kts, Vᵣ - 155 Kts, V₂ - 162 Kts.

起飞条件下计算的V速如下：

V₁（决断速度）：153节

Vᵣ（抬轮速度）：155节

V₂（安全爬升速度）：162节

The A-SMGCS replay of the flight was also carried out after the accident. The aircraft was observed departing from the bay 34 at 07:48:38 UTC. The taxi clearance was received at 07:55:15 UTC and the aircraft taxied from the bay at 07:56:08 UTC. The aircraft taxied to Runway 23 via Taxiway R4, backtracked and lined up. The take-off clearance was issued at 08:07:33 UTC. The aircraft started rolling at 08:07:37 UTC.
事故后回放了A-SMGCS（高级地面移动引导和控制系统）记录。飞机于07:48:38 UTC从34号停机位推出。07:55:15 UTC收到滑行许可，07:56:08 UTC开始滑行，通过R4滑行道前往23号跑道，掉头并对正跑道。08:07:33 UTC收到起飞许可，08:07:37 UTC开始滑跑。

As per the EAFR data, the aircraft crossed the take-off decision speed V₁ and achieved 153 kts IAS at 08:08:33 UTC. The Vᵣ speed (155 kts) was achieved as per the EAFR at 08:08:35 UTC. The aircraft air/ground sensors transitioned to air mode, consistent with liftoff at 08:08:39 UTC.
根据EAFR（增强型飞行数据记录）数据，飞机于08:08:33 UTC通过V₁决断速度（153节），08:08:35 UTC达到抬轮速度Vᵣ（155节）。08:08:39 UTC，空地传感器状态切换为“空中模式”，表明飞机已完成起飞。

The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec. The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off.
飞机于08:08:42 UTC达到最大记录空速180节。紧接着，1号和2号发动机的燃油切断开关在1秒间隔内相继从“RUN”位置切换至“CUTOFF”位置，导致N1与N2转速下降，说明燃油供应被切断。

In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so.
驾驶舱语音记录中，一名飞行员问另一人为何切断燃油，另一人回应自己没有这么做。

The CCTV footage obtained from the airport showed Ram Air Turbine (RAT) getting deployed during the initial climb immediately after lift-off (fig. 15). No significant bird activity is observed in the vicinity of the flight path. The aircraft started to lose altitude before crossing the airport perimeter wall.
机场监控录像显示，飞机在起飞后初始爬升阶段即部署了冲压空气涡轮（RAT）（见图15）。飞行路径周围未发现明显鸟类活动。飞机在尚未越过机场围墙前就开始失去高度。

Figure 15 CCTV screenshot of RAT Deployment

图15：闭路电视截图显示冲压空气涡轮（RAT）展开

As per the EAFR data both engines N2 values passed below minimum idle speed, and the RAT hydraulic pump began supplying hydraulic power at about 08:08:47 UTC.
根据增强型飞行数据记录（EAFR）数据，两台发动机的N2值降至最低怠速以下，冲压空气涡轮（RAT）液压泵约在08:08:47 UTC开始供给液压动力。

As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC.

根据EAFR记录，1号发动机的燃油切断开关约在08:08:52 UTC从“CUTOFF”切换至“RUN”状态。

The APU Inlet Door began opening at about 08:08:54 UTC, consistent with the APU Auto Start logic.
辅助动力装置（APU）进气门约在08:08:54 UTC开始打开，与APU自动启动逻辑一致。

Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN.
随后在08:08:56 UTC，2号发动机的燃油切断开关也从“CUTOFF”切换至“RUN”。

When fuel control switches are moved from CUTOFF to RUN while the aircraft is inflight, each engine’s full authority dual engine control (FADEC) automatically manages a relight and thrust recovery sequence of ignition and fuel introduction.
当飞机在空中时，燃油控制开关从CUTOFF切换至RUN，发动机的全权限双通道电子控制系统（FADEC）会自动执行重新点火与推力恢复的程序，包括点火与燃油重新引入。

The EGT was observed to be rising for both engines indicating relight.
观察到两台发动机的排气温度（EGT）上升，表明点火成功。

Engine 1’s core deceleration stopped, reversed and started to progress to recovery.
1号发动机的核心转速减速趋势停止，随后逆转并开始恢复。

Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery.
2号发动机虽然重新点火成功，但未能阻止核心转速下降，只能反复注入燃油以促使加速与恢复。

The EAFR recording stopped at 08:09:11 UTC.
EAFR记录在08:09:11 UTC停止。

At about 08:09:05 UTC, one of the pilots transmitted “MAYDAY MAYDAY MAYDAY”.
约在08:09:05 UTC，一名飞行员发出了“MAYDAY MAYDAY MAYDAY”紧急呼叫。

The ATCO enquired about the call sign. ATCO did not get any response but observed the aircraft crashing outside the airport boundary and activated the emergency response.
空管员（ATCO）询问呼号，但未收到回复，随后观察到飞机在机场围界外坠毁，并立即启动了应急响应程序。

At 08:14:44 UTC, Crash Fire Tender left the airport premises for Rescue and firefighting.
08:14:44 UTC，机场的应急消防车离开机场执行救援与灭火任务。

They were joined by Fire and Rescue services of Local Administration.
地方政府的消防与救援部门随后也加入了行动。

不管是何种原因，及时、严谨、透明的事故调查，都能成为让系统更加安全的保障。