For the multi-engine and commercial pilots, I am curious, what would cause the ATR72-600 to so suddenly go wing down to the left? If you watch the video the plane is seemingly in a roughly normal flight attitude as it approaches the bridge and the river, then suddenly it tilts strongly to port. Was the pilot trying to turn to square with the river or was something else likely going on?
It was a stall and he was low and slow before the stall. The pilot held it together as long as he could but eventually ran out of altitude, airspeed, and ideas.
There was a mayday about an engine flameout. That would be the first place to look. No question he was short on power for some reason.
Sad.
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Posts: 22445 | Location: Occupying Little Minds Rent Free | Registered: 04 October 2012
No question it was not going to end well, I just found it odd that he went from a wings level attitude to an 70-80 degree bank so quickly. Did a good job missing all those buildings I have to say.
And it looked like the left prop was feathered too (which I am sure is to your point about the left wing not producing lift). Pity though. You wonder if he had been able to clear the bridge and maintain a roughly wings level attitude if he could have ditched in the river with some less loss of life.
Originally posted by MJines: For the multi-engine and commercial pilots, I am curious, what would cause the ATR72-600 to so suddenly go wing down to the left? If you watch the video the plane is seemingly in a roughly normal flight attitude as it approaches the bridge and the river, then suddenly it tilts strongly to port. Was the pilot trying to turn to square with the river or was something else likely going on?
It was not a stall. It was a classic VMC induced roll. Velocity Minimum Control (VMC) in simple terms is the minimum speed you need to have sufficient air flow over rudder to counteract the asymmetrical thrust of the good engine. Get below that speed on one engine and the rudder can no longer overcome the asymmetric thrust and the aircraft will roll over into the side with the dead engine. Basic multi engine flying 101.
Why they were unable to maintain altitude on one engine remains to be seen.
Surestrike has it. Pilot error. The most fundamental and important maneuver every non CL thrust multi engine pilot learns. Sad. Refer to my Air Asia post about possible reasons that this basic stick and rudder skill was terribly lacking
Having flown may turbo props (not the ATR 72) Rest assured they perform quite well in my experience on one engine. In fact they have to to meet FAR 25 certification. That is if you do your part. The only question I have if for some reason it did not feather. They are supposed to fly with a windmilling prop as well but performance would be degraded. VMC roll over is a loss of control plain and simple
The preliminary FDR data indicates a very serious problem in the cockpit. Why would the PIC reduce power on the good engine at such a low altitude and not continue to fly the plane to a safe altitude? Looks like someone may have forgotten basic airmanship.
quote:
Both engines had trouble in Taiwan TransAsia crash, black-box data shows
5:27 a.m. ET
The right engine of TransAsia Airways Flight 235 triggered an alarm and then went idle 37 seconds after the plane took off from Taipei's airport, Taiwan Aviation Safety Council head Thomas Wang said Friday, citing preliminary findings from the flight data and cockpit voice recorders. Another 46 seconds after that, the pilots apparently revved down the left engine in an attempt to restart both motors. Unfortunately, 72 seconds after that, the plane crashed into Taipei's Keelung River.
At least 35 of the 58 people on board died, including the pilot, who was reportedly found clutching the flight controls. Eight people are missing, and 15 survived the crash. The right engine did not "flame out," as the pilot said in his mayday call, meaning fuel wasn't getting to the engine or it failed to combust, Wang said, and the black boxes will be analyzed in greater detail to try to figure out what went wrong. "It's only the third day so we can't say too much," he said. "We haven't ruled anything out."
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Posts: 22445 | Location: Occupying Little Minds Rent Free | Registered: 04 October 2012
After reading the preliminary reports and watching the accident from several different views it does in fact look like it was an aerodynamic stall and spin entry.
They lost the RIGHT engine after takeoff then feathered the LEFT engine. In the process of trying to get the left engine restarted they traded altitude for airspeed until they stalled.
Just an FYI everybody with the exception of Japan, stay the HELL off of Asian air carriers. These types of pilot error induced accidents are endemic to the region. There is a cultural issue here which precludes these cultures from safely operating an airplane.
I'll throw out a perfect example here. Several years ago a good friend interviewed for a Chinese Airline that was paying very well for expat pilots. During the interview simulator ride they threw all kinds of emergencies at him which he handled well. On final they gave him a flap and gear failure. So he did the absolute 100% correct thing which was to go around gain some altitude and work the problem then come back for a landing after you've made the aircraft as safe as possible and had time to coordinate for rescue equipment ETC ETC. He did this even though the interview captain was yelling at him to LAND, LAND NOW!!
After a successful landing the interview captain was disgusted with the interviewees choice to go around and informed him that he'd NEVER work for the Chinese airline in question. Because it was an insult to go around and an even bigger insult to not obey the commands of a senior company official. My buddy gathered his stuff and told the Chinese Captain that he was right, he'd never work for that airline and just in case he was interested the episode that just occurred was a perfect example of why the Chinese crash airplanes at a rate of about 2000% higher than the rest of the industrialized world.
The chief pilot at a commuter I once flew for had a bit of advice for second officers regarding questioning captains...."Who are you willing to let kill you"?
Posts: 911 | Location: Minnesota | Registered: 09 January 2005
Engine Failure, Related Procedures Focus Of TransAsia Probe
Feb 6, 2015Bradley Perrett | Aviation Daily
BEIJING—Neither engine on the TransAsia Airways ATR 72-600 that crashed in Taipei on Feb. 4 was generating thrust before impact after one failed and the other was apparently shut down by the crew, investigators have determined.
The aircraft’s right (No. 2) engine propeller automatically feathered as an engine-flameout warning was sent to the cockpit shortly after takeoff, preliminary findings revealed by Taiwan’s Aviation Safety Council (ASC) indicate. Flight data recorder (FDR) readings and cockpit voice recorder interpretation suggest the crew then shut down the left (No. 1) engine.
The Civil Aviation Administration grounded all Taiwanese ATR 72s operated by TransAsia and Uni Air, and ordered checks on the fleet’s engines and fuel systems. TransAsia, which suffered another fatal ATR 72 crash seven months ago, has been banned from applying for new routes for a year.
The Flight GE235 crew struggled to deal with the loss of thrust for about 2.5 min. before impact, with repeated stall warnings beginning 1 min. 27 sec. before the cockpit voice recording ended. Of the 58 people aboard the TransAsia flight, 43 are dead or missing, including the two pilots.
The ATR 72’s right engine triggered an alarm about 37 sec. after the 10:52 a.m. takeoff at an altitude of 1,200 ft. (370 meters). But that engine did not stop running, even though a pilot told the control tower that the aircraft suffered an engine flameout, ASC Director Thomas Wang told reporters. FDR data indicate the engine auto-feathered, aligning the propeller blades with the line of flight and therefore ceasing to generate thrust. Oil pressure remained normal.
One of the pilots then shut down the left engine for an unknown reason, Wang says. The FDR data indicates that the left engine’s throttle was reduced over a period of about 30 sec., and then its fuel valve was shut off. The crew then attempted to restart the left engine, but ran out of time.
The left-engine shutdown and right-engine failure left both props feathered for most of the last minute before impact, causing the aircraft to slowly lose altitude and crash.
There were no apparent problems with the engines before the flight. The last stall warning lasted until about 3 sec. before the voice recording ends.
A preliminary report is due within 30 days, a more extensive one in 3-4 months, a final draft within 8 months, and completion of the investigation in about a year.
The council issued the sequence of events in Chinese, explained with maps. Translated to English and slightly edited, the sequence was:
10:41:15 The recording begins.
10:51:13 The control tower at Taipei Songshan airport authorizes takeoff.
10:52:01 approximately, the aircraft takes off [begins takeoff roll, apparently].
10:52:38 Master warning for No. 2 engine, a few hundred meters from the runway.
10:52:42 No. 1 engine is throttled down.
10:53:00 A crew member mentions engine shutdown procedures.
10:53:06 A crew member mentions throttling down the No. 1 engine.
10:53:08 A crew member confirms No. 2 engine flameout.
10:53:10 Stall warning.
10:53:13 Stall warning.
10:53:20 A crew member mentions feathering and stopping fuel supply to No. 1 engine.
10:53:21 Stall warning.
10:53:24 No. 1 engine is shut down.
10:53:26 Stall warning.
10:53:35 A crew member calls “Mayday mayday mayday. Engine flameout.”
10:53:56 Stall warning.
10:54:06 Stall warning.
10:54:09 A crew member mentions engine restart.
10:54:20 [Attempted] restart of No. 1 engine.
10:54:12 Stall warning.
10:54:23 Stall warning.
10:54:34 Master warning.
10:54:37 The recording ends.
Times have been rounded to the nearest second.
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Posts: 22445 | Location: Occupying Little Minds Rent Free | Registered: 04 October 2012
I only have a PPL single engine, but since the first time I saw that video, and the sat map of the flight path, I wondered two things: why the hell an Airline pilot would try to "keep the aircraft off the ground" in an attitude that screams "incipient stall" and is definitely not glide speed - and why did he not head for the nearby river, which was not a very good emergency strip, but a million times better than the city he was overflying?
I trained in South Africa, and these were things that were ingrained into us in flying school. Engine off - DROP YOUR NOSE; always know where you'd drop your plane in an emergency, always rehearse the worst case scenario in your mind so you'll know what to do the day it happens, and practice, practice, practice. We were not "told" about stall-spins, we had to practice them and demonstrate recovery from an incipient spin (not that in this case they could have recovered anything, but they should NOT have been in a stall-spin situation). We had throttles pulled immediately after take-off, and were judged on the instinctive reaction (guess what: if the stick went or stayed aft, that was a fail...).
It seems to me that too many ATP lack basic stick training and skills, and I keep wondering: why???
Philip
Posts: 1252 | Location: East Africa | Registered: 14 November 2006
OK not a VMC but a total clusterf*ck. If they still had the good engine they would have still crashed by the looks of their piloting ability. So they turned it into a glider and crashed. Par for the course over there it seems. Looks like they ran out of altitude and airspeed in their "glider"
Is there a chance they shut down the wrong engine by mistake? peter
Be without fear in the face of your enemies. Be brave and upright, that God may love thee. Speak the truth always, even if it leads to your death. Safeguard the helpless and do no wrong;
If you can follow the FDR timetable presented above (assuming it is correct) they did in fact shut down the wrong engine. So yes, it was a deadly mistake (assuming they were not attempting to commit suicide and mass murder at the same time).
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Posts: 22445 | Location: Occupying Little Minds Rent Free | Registered: 04 October 2012
Thanks! I just wasn't sure whether there was some technical/procedural reason why the other engine was shut down. Peter
Be without fear in the face of your enemies. Be brave and upright, that God may love thee. Speak the truth always, even if it leads to your death. Safeguard the helpless and do no wrong;
