I read an article in Flight Safety Foundation’s Aviation Safety Network about the TransAsia Airways flight GE235 ATR accident after departing Songshan airport in Taipei, Taiwan:
I would have been content to criticize the circular for erroneous reporting – and I’m convinced the reporter had not read the report – but the Aviation Safety Council (ASC) report itself dwelled into conjecture. ‘Had the crew prioritized their actions to stabilize the aircraft flight path, correctly identify the propulsion system malfunction which was the engine number 2 loss of thrust and then take actions in accordance with procedure of engine number 2 flame out at take-off, the occurrence could have been prevented.’ This sounds a lot like speculation and not fact; another name for Monday Morning Quarterbacking.
The probable cause of the accident was a problem with the Automatic Feathering Unit (AFU) on the #2 engine; to be clear, the engine manufacturer (per the report) knew of an anomaly with the AFU and was trying to fix it. Coupled with this, the airline had not generated proper procedures for engine stalls or even ATR72-600 differences training. But according to the article and the ASC report, the pilots were not up to the task, even shutting down the wrong engine.
Per the transcript, at 10:52:38 the first problem occurs when a Master Warning sounds; at 10:52:39, the Captain takes control and pulls back the throttle on #1 engine; this was most likely done to minimize induced yaw from the good engine. They then follow the heading bug while adjusting speed and trim as they fly over Taipei. Around 10:53:00 the #2 engine flames out, which is confirmed at 10:53:07. Even though they fail to ever re-engage the autopilot, the pilots are calm and communicating. Between 10:53:08 and 10:54:05, stall warnings, sticker shakers, terrain warnings (buildings) and an inability to engage the autopilot monopolize their conversation. At 10:54:07 the first officer announces that both engines have flamed out; there is no mention of intentionally turning off #1 engine. For the next 24 seconds, as the captain dodges buildings and flies the aircraft-turned-glider, the first officer tries to start an engine. At 10:54:31 the aircraft impacts the bridge; the aircraft’s emergency lasted 113 seconds.
I’ve worked with the ASC before; they do great work and are very tenacious. I’m struck by many instances of speculation in the factual part of the report. I admit I haven’t heard the recorders first hand, but the words in the transcript are unmistakable – there was no ‘decision’ to shut down the number one engine.
I was also struck by the assumptions of the Flight Safety Foundation’s article and wish they would have better reviewed the final report. Their twitter person also seemed to be out of touch with the information relayed in the report. The fact that the AFU malfunctioned and may have contributed to the confusion with the good engine appears to be less reportable than the pilots’ culpability. It also needs to be mentioned that the difficult obstacle course the pilots flew through at the end should not to be underestimated. And as a final note, pilots are not maintenance troubleshooters; they don’t have the technical background to determine most problems, especially one that doesn’t behave like normal.