Former Member Posted February 5, 2015 Share Posted February 5, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Monz Posted February 6, 2015 Share Posted February 6, 2015 Ummm, no Area51. Do you know what Vmca is?? Vmca is defined as the minimum speed, whilst in the air, that directional control can be maintained with one engine inoperative (critical engine on two engine aeroplanes) The first C90 is a classic LOC (Loss Of Control) by not maintaining Vmca. Just about all multi engine aircraft SOP's are rudder away from dead engine (dead engine, dead leg) and 5° opposite roll to counter the asymmetric thrust and maintain level flight. The second is letting airspeed bleed below Vmca on final with power on. Look how quickly it snaps in. The images show a port prop in coarse pitch, 'windmilling' is not discernible. The starboard prop seems to be in fine pitch. From ATR pilots with thousands of hours: The normal climb schedule for the ATR72-600 (that is the newest model with full FADEC engines) calls for acceleration at a certain altitude (normally 400', but that can change with obstacle clearance limitations). You will get airborne at a speed somewhere between Vr and V2 and climb at V2 plus 10 or so kts until the accell altitude, where the power levers are pulled out of the T/o detent into the Climb detent. At this moment, you lose auto uptrim (more power from remaining engine if the other fails) and autofeather. It means that if an engine fails after this selection of the power levers (they apparently call them Power Management Selectors (PMS)), the crew are responsible to select more power (max power/max continuous power) and they have to manually feather the dead engine. Failing to do either or both will have significant consequences. The windmilling prop will have tremendous drag, because the CSU will immediately go full fine pitch to hold the RPM constant. Climb power would be somewhat less than full power on the live engine and with the nose high because of the climb, there will have to be an immediate and positive pitch forward to keep the speed from dropping to the wrong side of the drag curve or (God forbid) below Vmca or Vs. Quote Link to comment Share on other sites More sharing options...
Monz Posted February 6, 2015 Share Posted February 6, 2015 From an ATR pilot: Assuming that the accelaration altitude was 400' AGL as part of the Climb Sequence the Power Management Selector is selected to CLIMB which disarms the ATPCS (Automatic Takeoff Power Control System) which is responsible for Uptrim as well as Autofeather. In this case there will be no Autofeather and the unfeathered prop will cause alot of drag until manually feathered by the crew. Losing an engine in a ATR72 at about 1300' feet shouldn't be a problem, however it is still close to the ground and the best action would be to revert to the Takeoff scenario which is well documented in the ATR QRH. Quote Link to comment Share on other sites More sharing options...
Monz Posted February 6, 2015 Share Posted February 6, 2015 Further on the design and handling of the aircraft:F From my time on the ATR, some statements will always stick in my mind the ATR is a new generation efficiently designed aircraft, not over engineered like its counterpart the Dash 8 300 or Q400 that being described to me by the instructor on the technical course in Toulouse, that nothing is engineered bigger or bulkier than was absolutely necessary, he used the Tailplane and elevator as an example, where the ATR tailplane/elevator is EXACTLY the correct size to meet the parameters required,and not one inch larger just for some extra controllability, but that made it "almost" under controlling when compared to the unnecessary large tailplane/elevator on the dash-8 Quote Link to comment Share on other sites More sharing options...
Paul Jefferies Posted February 6, 2015 Share Posted February 6, 2015 It is nice to see some informed comment and particularly that others have also identified that in this, as in other accidents, whatever other factors may be involved, failure to achieve Vmca would appear to be the ultimate reason for the aircraft going out of control......... Following the accident in the USA which I mentioned in a posting above, I wrote to the BMFA pointing out that the rules for flying multi engined models in public displays should be reviewed to ensure that anybody flying such models at public displays is aware of Vmca and should pass a test to show that they can control an Engine Failure on Take-Off. After several exchanges of correpondence the BMFA said that they thought existing regulations were adequate.......... I was not happy with this so I wrote to the LMA with the same result. I feel very strongly that If an accident such as happened in the USA can happen over there, it could also happen here and that if demonstration pilots have not had proper training and are not fully aware of the problems involved in an engine failure, this is an accident waiting to happen at a public display in this country. Because of my concern over this issue I then wrote to the CAA who, despite follow up phone calls, have also done NOTHING! At this point I have to confess that I gave up........... As a post-script to the above saga I would just like to add that I have subsequently spoken to a very well known competition, display and film pilot, who has flown several multi-engined models in public and he candidly admitted that he was unaware of Vmca but fortunately had not suffered any engine failures....... MULTI ENGINED AEROPLANES ARE DIFFERENT TO SINGLE ENGINED AEROPLANES which is why, in the fullsize world extra training and qualifications are needed before you are allowed to fly them. This should also be the case when multi-engined models are flown in public displays. Paul Quote Link to comment Share on other sites More sharing options...
Paul Jefferies Posted February 6, 2015 Share Posted February 6, 2015 For those that didn't see it first time round, this is the accident to which I was referring above:- It looks depressingly similar to the Transasia accident and with our regulations as they stand at the moment, it is only a matter of time until it happens at a model show in this country. Paul Edited By Paul Jefferies on 06/02/2015 13:42:19 Edited By Pete B - Moderator on 06/02/2015 14:03:26 Quote Link to comment Share on other sites More sharing options...
kc Posted February 6, 2015 Share Posted February 6, 2015 News reports say both engines failed on the TransAsia plane. Quote Link to comment Share on other sites More sharing options...
Monz Posted February 6, 2015 Share Posted February 6, 2015 Posted by kc on 06/02/2015 14:12:08: News reports say both engines failed on the TransAsia plane. They shut down the incorrect engine. **LINK** Quote Link to comment Share on other sites More sharing options...
Area 51 Posted February 6, 2015 Share Posted February 6, 2015 Posted by Area 51 on 05/02/2015 23:38:21: Classic FAILS on behalf for the King Air guys.. As previously stated re the King Airs...... a failure to maintain forward speed... Quote Link to comment Share on other sites More sharing options...
Jon H Posted February 6, 2015 Share Posted February 6, 2015 Latest info from black boxes confirms DOUBLE engine failure. The left engine was fully shut down as they went through the relight procedure. http://www.bbc.co.uk/news/world-asia-31162351 Edited By Jon Harper on 06/02/2015 16:55:12 Just read the link monz put up, wouldn't be the first time the wrong engine has been shut down but I am curious to know how that site got its information so fast, and why the right engine is clearly running in the video and the left is stationary. If the prop had fully feathered on both engines they should both be doing similar rpms unless one was powered. Edited By Jon Harper on 06/02/2015 17:07:07 Quote Link to comment Share on other sites More sharing options...
Paul Marsh Posted February 6, 2015 Share Posted February 6, 2015 Odd that both engines would revert to idle via auto throttle. The auto throttle is linked to each engine Fadec, that looss of power on one engine would let the pilot assess the situation by preventing adverse yaw from a dead engine by throttling back the other engine and would allow the pilot to assert yaw control and increase power respectively on the good engine - but this needs time and if it happens close to the ground obviously this didn't work in this case. Shutting down both engines doesn't make sense, unless as in Flight 92 pilots got confused to their instruments and shut down a good engine then they realized that they shut down the good engine and crashed over the M1 motorway. Quote Link to comment Share on other sites More sharing options...
John Privett Posted February 6, 2015 Share Posted February 6, 2015 There's lots of discussion (as you'd expect!) over on the Professional Pilots Rumour Network (PPRUNE) and it does look like human error... Briefly it appears that engine no. 2 (right) failed, and went to idle - reason unknown. Automatically the power to engine no. 1 (left) increased (an air bleed valve is shut) - this is to provide more power to keep the aircraft flying. It seems the ATR-72 is not exactly over-powered. Shortly afterwards engine #1 is throttled back manually a little, then progressively more and more and finally shut down. Engine #2 is still idling. Airspeed and altitude are now low. Perhaps the error was then realised as attempts were made to restart engine #1, and seconds before the crash engine #1 is running again and accellerating up to speed - but too late... Two factors keep being mentioned. Firstly that on the flight deck was a third pilot, an instructor with more hours than either the Captain or co-pilot. His role is not known, but his presence could lead (so say pilots on PPRUNE) to an emergency situation being handled 'differently' - or even the more experienced instructor attempting to take over in the emergency. Secondly, there have been reports of engine problems - probably on the #1 engine - on previous flights, so the crew may have been concerned about possible problems with the #1 engine. So when the alarms started going off they'd be inclined to assume it was the #1 engine as they "knew" it was faulty... Quote Link to comment Share on other sites More sharing options...
Paul Marsh Posted February 7, 2015 Share Posted February 7, 2015 Getting to sound like flight 92 - shutting the wrong engine down. Quote Link to comment Share on other sites More sharing options...
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