Pegasus Airlines Boeing 737-800 TC-CPF overrun runway at Trabzon. All pax okay
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Interesting, they spent some time with is suspended, possibly checking LG or locking it down, and now it seems to be standing on its own LG. Quite surprised those were not damaged enough to prevent that.
Edit - ok looked back at vid, Left MLG looks intact but right has been ripped off. They are prepping a tug and bogie truck i guess to support under the right wing.
Edit - ok looked back at vid, Left MLG looks intact but right has been ripped off. They are prepping a tug and bogie truck i guess to support under the right wing.
Last edited by hoss183; 18th Jan 2018 at 13:17.
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Because TOGA had been inadvertently selected and the Autothrottle was still engaged,
Why was the AT still engaged at touchdown? Was the an autoload?
Why was the AT still engaged at touchdown? Was the an autoload?
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Yes:
If you watch the simulator reconstruction of the event (posted above), you can see that after touchdown, the PF removes his hand from the Right Thrust Lever to deploy the Left Thrust Reversor (the Right Thrust Reversor is inop). Because TOGA had been inadvertently selected and the Autothrottle was still engaged, as soon as the PF’s hand came off the Right TL, the Right TL advanced to TOGA Thrust and the Takeoff Configuration Warning activated.
If you watch the simulator reconstruction of the event (posted above), you can see that after touchdown, the PF removes his hand from the Right Thrust Lever to deploy the Left Thrust Reversor (the Right Thrust Reversor is inop). Because TOGA had been inadvertently selected and the Autothrottle was still engaged, as soon as the PF’s hand came off the Right TL, the Right TL advanced to TOGA Thrust and the Takeoff Configuration Warning activated.
In the 737 video the captain selects reverse for No 1, having left the autothrottle in TOGA, which produces an autothrottle commanded spool to N1 on No 2. if, and I mean if, the rumours are correct this will probably turn out to be a primary cause of the accident.
However, Boeing or Airbus, rumours true or otherwise, whenever a single TR is inop it seems to me that;
(1) If possible you would plan to land brakes only or
(2) If not possible/desirable you would have a heightened awareness of the interplay between the TR and associated systems such as spoilers and AT.
Either way the deployment of asymmetrical reverse thrust would feature significantly in the briefing.
As is usually the case additional pressures such as the cancelled go around, late decision height etc. seem to have contributed in lining up the holes. Hindsight is a great thing, but it now seems overriding the PF wasn't the smartest thing to do here. A go around together with second go at the landing config and briefing would have almost certainly saved the day.
Last edited by birmingham; 18th Jan 2018 at 15:37.
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The autothrottle in the B737 automaticly disengages two seconds after touchdown, provided is was armed. (Autoland or 'speed mode').
Also if there would be a split thust lever position, or a malfunction in the system was discovered, disconnect of the A/T would occur.
So much for the TOGA/GA 'armed' conspiracies.
Also if there would be a split thust lever position, or a malfunction in the system was discovered, disconnect of the A/T would occur.
So much for the TOGA/GA 'armed' conspiracies.
I think that is the root cause of the problem. If the outline of the accident as posted by OnTheNumbers is correct (the video reconstruction strongly suggests that it is), then the problem began when they transitioned to a visual approached and the F/O disconnected the automatics for a manual landing. But instead of disconnecting the AT, he pressed TOGA instead. The CPT took over, but never corrected the first error by disengaging the AT.
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I think that is the root cause of the problem. If the outline of the accident as posted by OnTheNumbers is correct (the video reconstruction strongly suggests that it is), then the problem began when they transitioned to a visual approached and the F/O disconnected the automatics for a manual landing. But instead of disconnecting the AT, he pressed TOGA instead. The CPT took over, but never corrected the first error by disengaging the AT.
On the other hand, in a time where I do not get a satisfactory answer from captains doing recurrent training, of the mechanics of 'Level Change', I am not easily surprised anymore.
A couple of points to add to the debate as a FWIW from a generic Boeing POV:..
1. The 777 has in part the following Autothrottle logic:
I have yet to find chapter and verse (if it exists) of whether that logic still applies in the event a reverse lever being raised after TOGA has been pressed.
Secondly there is a still current Ops manual Bulletin for the 777 from about two-three years back warning of :”Uncommanded Autothrottle Movement on the Ground”..which stated that “there have been reports of uncommanded Autothrottle advancement during ground operations.......In one report the autothrottles advanced after landing before speed brakes were retracted”
So, having thrown that into the mix do we still want to rush to hang the P1 of this 737 out to dry ? More importantly and obviously of more relevance is does anyone know and able to post what the 737-800 FCOM says if anything on this subject?
1. The 777 has in part the following Autothrottle logic:
Autothrottle disconnect occurs automatically:......
when either reverse thrust lever is raised to reverse idle
........
when either reverse thrust lever is raised to reverse idle
........
Secondly there is a still current Ops manual Bulletin for the 777 from about two-three years back warning of :”Uncommanded Autothrottle Movement on the Ground”..which stated that “there have been reports of uncommanded Autothrottle advancement during ground operations.......In one report the autothrottles advanced after landing before speed brakes were retracted”
So, having thrown that into the mix do we still want to rush to hang the P1 of this 737 out to dry ? More importantly and obviously of more relevance is does anyone know and able to post what the 737-800 FCOM says if anything on this subject?
Last edited by wiggy; 18th Jan 2018 at 16:58.
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No official confirmation of anything as yet. Even the inop thrust reverser is not confirmed. All the official sources have done is said the crew were sober and had difficulty braking on the wet runway
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The autothrottle in the B737 automaticly disengages two seconds after touchdown, provided is was armed. (Autoland or 'speed mode').
Also if there would be a split thust lever position, or a malfunction in the system was discovered, disconnect of the A/T would occur.
So much for the TOGA/GA 'armed' conspiracies.
Also if there would be a split thust lever position, or a malfunction in the system was discovered, disconnect of the A/T would occur.
So much for the TOGA/GA 'armed' conspiracies.
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To be fair, all they can hang the P1 on is taking over after a GA has been called and reversing the decision. I doubt he may have known the TOGA had been selected as he'd have had his eyes outside, would have pulled the levers back sharply and if single channel the autopilot disconnect wail is quite loud.
Having landed, either the A/T logic thinking it's in a Go around situation discounted the air/ground logic and 2 second cut out or a fault, may well have accounted for the thrust.
It was dark, poor vis and wet, not ideal conditions to see the lever move up, or fully be aware of the noise of a spooled up engine. Most of the 737 Pilots in Turkey seem to use Bose A20 headsets as well.
Remember the CRM gem of counting ball throws as bloke in the gorilla suit runs behind? So concentrated most don't even see him.
Perhaps the T/O Config horn falls under that chapter.
Food for thought. And a definite Swiss Cheese event if there ever was one!
Having landed, either the A/T logic thinking it's in a Go around situation discounted the air/ground logic and 2 second cut out or a fault, may well have accounted for the thrust.
It was dark, poor vis and wet, not ideal conditions to see the lever move up, or fully be aware of the noise of a spooled up engine. Most of the 737 Pilots in Turkey seem to use Bose A20 headsets as well.
Remember the CRM gem of counting ball throws as bloke in the gorilla suit runs behind? So concentrated most don't even see him.
Perhaps the T/O Config horn falls under that chapter.
Food for thought. And a definite Swiss Cheese event if there ever was one!
Nah. I don't buy that at all.
TOGA thrust on a 738 produces a massive surge in power and pitch up. There is no way a competent pilot could take control and not notice, let alone hold the thrust levers shut against the servos and not notice, and nor is it feasible that a pilot of any experience level could fail to notice one engine producing max reverse thrust while the other is producing TOGA thrust; the yaw shortly after touchdown would be massive and they would have exited stage left far earlier in the landing roll if that had occured.
TOGA thrust on a 738 produces a massive surge in power and pitch up. There is no way a competent pilot could take control and not notice, let alone hold the thrust levers shut against the servos and not notice, and nor is it feasible that a pilot of any experience level could fail to notice one engine producing max reverse thrust while the other is producing TOGA thrust; the yaw shortly after touchdown would be massive and they would have exited stage left far earlier in the landing roll if that had occured.
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Another theroy:
The aircraft landed in TO/GA mode. As it was in TOGA mode, the A/T logic didn't take into account that the aircraft was on the ground (it is not uncommon to touch the runway during a GA). As the aircraft was in TO/GA mode the TR of the left engine didn't activate in spite of lever movement. (Is this possible???). Additionally the right engine needed time for spool up.
So, no TR on the left engine and slowly spooling up turbine of the right engine may have prevented the expected massive yaw during the initial phase of the landing roll.
The aircraft landed in TO/GA mode. As it was in TOGA mode, the A/T logic didn't take into account that the aircraft was on the ground (it is not uncommon to touch the runway during a GA). As the aircraft was in TO/GA mode the TR of the left engine didn't activate in spite of lever movement. (Is this possible???). Additionally the right engine needed time for spool up.
So, no TR on the left engine and slowly spooling up turbine of the right engine may have prevented the expected massive yaw during the initial phase of the landing roll.
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Don't know about the rest of the world, but for us,
transfer of ac below 500' = GA
the increase in thrust from pressing GA would have resulted in an unstable approach = GA
transfer of ac below 500' = GA
the increase in thrust from pressing GA would have resulted in an unstable approach = GA
Airlive providing this quote from the pilot...
“The plane made a normal landing. Once we came to the end of the runway, we tried to maneuver to the right. Just as we were about to maneuver, the right aircraft engine started to accelerate. The plane should have gone right, but because of the right engine, it suddenly started going leftwards and went down the slope in the direction of the [Black] Sea,” .
“The plane made a normal landing. Once we came to the end of the runway, we tried to maneuver to the right. Just as we were about to maneuver, the right aircraft engine started to accelerate. The plane should have gone right, but because of the right engine, it suddenly started going leftwards and went down the slope in the direction of the [Black] Sea,” .
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Is this the case ? I understood the FO mistakenly pushed the TOGA Pb instead of disengaging the A/T (commom error) and the CP took over quickly but forgot to disengage the A/T.