In February I posted a note about TransAsia 235, the turboprop that crashed in Taiwan. I suggested that, in the event of an engine failure, the pilots didn’t have to do much of anything other than fly the airplane. The official factual report is now available.
The engine failed about one minute after take-off (see page 12). Automated systems then shut off bleed air from the good engine, so as to maximize its available power (bleed air from the compressor is used to run pressurization and de-icing), temporarily relaxed a power limit to the good engine (“uptrim”), and, more important, feathered the prop on the failed engine so as to reduce drag. At this point all the pilots had to do was leave the throttles pushed full forward and fly. The pilot flying (PF), however, pulled back the throttle on the good engine about five seconds after the bad engine failed, ignoring the PM’s (pilot monitoring) suggestion to “wait a second cross check.” (A third pilot, an “observer” (OBS), sat behind the PF/PM in the front seats.) With no power on one side and limited power on the other side the airplane crashed about two minutes later.
Not a great day for John Henry…
[Illustrating the human bias towards action, the press coverage of this latest discovery has failed to mention “doing nothing” as a superior alternative to what the pilots actually did. A non-pilot reader would be left with the impression that the crew should have moved at least some levers but unfortunately moved the wrong one when in reality a far better course of action would have been to touch nothing. (Corollary to the First Principle of Flying Jets: “If a switch has dust on it, don’t touch it.”)]
Related:
- my syllabus for multi-engine training in a crummy piston-powered twin
- part of my email report on flying a Beriev Be-103: “pulling an engine back to zero thrust is an experience you won’t soon forget. The yaw isn’t that dramatic because the engines are inboard. What is dramatic is the sink rate at blue line. We were at 3000′ on a cold day and couldn’t hold altitude. It turned out that we’d [we = TWA captain demo pilot plus newbie (me)] left the cowl flaps [air inlets to cool the engines at high power settings] open and that was enough to rob us of the advertised 3000′ service ceiling. A piston twin is a pretty bad aircraft and an underpowered piston twin is scary bad. The ship has 210 HP per side. It probably should have at least 250 or, better yet, a single 450 HP turbine.”