Air India Runway Excursion
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I asked a friend of mine who's flying the 737-800 to do the landing computation at the exact same weather condition and runway as I did on A320 CEO with Sharklets. For standard condition and a weight of 60T the VAPP on 737 is 138kt versus 135kt on A320. The landing distance with manual braking is 1207 meters versus 1153 meters on A320. So unless I'm missing something the 737 is slightly more prone to overrun the runway than an A320.
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For those questioning the regulator/airlines on number of approach policies before a mandatory diversion , due to a fog related incident at an airline a few years ago, the regulator did come with guidance and I know the airline I worked at changed our OM policy to maximum 2 approaches/ go-arounds due to meteorological reasons before a mandatory diversion. I would expect AI/AIE to have something similar .
I'm waiting for something official from the investigators than depending on some photos/passenger reports to make an assessment of contributing factors , causal factors and recommendations and make my own lessons learnt so that it doesn't happen again .
Last edited by masalama; 10th Aug 2020 at 04:32. Reason: grammar
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I continue to be amazed that there is little attention or monitoring given to the fact that a large proportion of 737 pilots seem to chase the VApp bug after the threshold, even to the extent of adding thrust in the flare! - Instead of TLs closed and flaring to an attitude, touching down at~Vref.
This mishandling leads to long landings and high touch down speeds.
This mishandling leads to long landings and high touch down speeds.
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I think you are correct. I have had colleagues calling "speed" when the speed goes between Vref+5 and Vref.
I even had an instructor write up on a line check that I had allowed the FO to fly at Vref-5 when he meant Vref+5 minus 5!
In other words, not calling him out for applying the FCTM technique.
Not saying this applies here. Just sayin.
I even had an instructor write up on a line check that I had allowed the FO to fly at Vref-5 when he meant Vref+5 minus 5!
In other words, not calling him out for applying the FCTM technique.
Not saying this applies here. Just sayin.
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I think you can probably guarantee the aircraft was not at the correct speed. I’ve not flown the 737 for a bit, but I remember if you let the speed get below Vref in the flare, it would get on the back of the drag curve and crunch into the deck. This is why pilots would often fly (and justify flying) well above the command speed. Even worse, when increments were added to the command speed to account for the gust factor, they would fly well above that command speed. Throw in a long landing, wet runway and maybe a glitch with the spoilers or a reverser, then such pilots could find themselves in deep trouble.
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So I am a little confused. The opinion is that the crew had configured for a go around, boards are stowed, throttles forward and flaps 1 in the detent. At what point would this decision have been made I wonder? I mean surely not at 40 kts with the aircraft about to falloff the end of the runway? Yet the final resting place of the aircraft would suggest what ever forward momentum it had was effectively used up in the slide down the hill and the abrupt stop when it reached the pavement. The impact of course caused the forward fuselage section to buckle upwards and break off before sliding into the nearby wall. But none of this suggests the aircraft 'flew' off the end under T/O power as you might imagine say a failed launch off an aircraft carrier. If that had been the case, then the impact would have been some distance further on and of course casualties would have been much higher if not a complete disaster. Instead, this aircraft seems to have literally flopped off the end. I might hazard a guess that it wasn't the wall that caused the crew casualties but rather the impact with the pavement after the slide down the hill.
Just cant imagine the circumstances for all this to happen. How long does it take to spool up, how long does it take for the flaps to come up from 30 or 40 to 1 ? How close to the runway end do you have to be before you say, nah let's give this away. Or put another way, if you fall off the end at 40 kts or so, when did you make your go around decision with a 13 kt tail wind? I mean surely, before you commit to take the aircraft back into the air again, you have to have assessed there is a better that even chance the aircraft will in fact get airborne in the what's left of the runway?
The flap handle was in the flap 1 detent and this is what flap 1 looks like on a B737-800 as far as I can ascertain:
But this what the flaps looked like on the accident aircraft where you can see the flaps appear to be extended much further. Note the trailing flap devices and how their hinges are visible whereas in the image above these cant be seen. So what does this suggest? Someone has played with flap lever perhaps as part of removing the crew? Or, were the flaps still travelling as the aircraft plunged off the end? In which case this go around must have been desperate affair.
I imagine the near destruction of the engines on the slide down the slope and possibly the lights going out gave rise to the reports of 'heroic' actions by the pilot in turning off the engines.
EDIT: Subsequent imagery makes it very clear the the flap lever is in the 40 deg detent.
Last edited by Lord Farringdon; 10th Aug 2020 at 20:45. Reason: Edit based on new imagery.
Start levers in IDLE contradict that supposed ‘heroic’ last-seconds engine shutdown.
Normal go-around flap setting would be flaps 15, but the flap lever seems further aft.
Speed brakes not extended (and speed brake lever stowed) definitely could be a major contributing factor in the overrun!
Normal go-around flap setting would be flaps 15, but the flap lever seems further aft.
Speed brakes not extended (and speed brake lever stowed) definitely could be a major contributing factor in the overrun!
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You are correct. B737 800 is a stretched aircraft and to avoid tail strike on To and landing the speeds are higher than previous models. On MAX to fit bigger engines it even went to ridiculous length to raise the nose wheel by 9 inches and fitting engines further forward and upward shifting the thrust line. On MAX 900 that was also not enough so on takeoff run the main wheel extends during rotation. It's highly compromised aircraft to meet certification. In India all overruns are on B737.
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Even worse, when increments were added to the command speed to account for the gust factor, they would fly well above that command speed. Throw in a long landing, wet runway and maybe a glitch with the spoilers or a reverser, then such pilots could find themselves in deep trouble.
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Calicut RWY 10 Disaster
I am an expat pilot and TRI and previously worked for AIX.. in the early days of their operation, and actually was based in Calicut from 2003-2005 before moving to the Gulf from where i continued to visit the field on a regular basis untill as recently as March 2020.
Over the years the approach to RWY 10 has always been "problematic" because of its visual and environmental "characteristics". In the early days it was a visual approach only. Then they put a VOR approach, then with in the last few years because of the Indian Airports "modernization" the upgraded to an ILS RW10 approach. However the Approach minimums though lower. Have been off set by the fact that the Landing distance beyond the glideslope is less. Also the visual appearance on breakout gives the appearance of a twisted runway. And following the Glideslope to touchdown puts you 1000 Meters beyond the touchdown point. Which on a dry day with Autobrake 3 or max braking takes you to the end!!
The ATC facility at the Airfield either do not know or haven't received proper training on how to use the radar. And either are not willing to or for some unexplained reason cant give proper assistance to pilots during times of Monsoonal weather in the area.They relay on Cochin approach to give the clearance to intercept the final track inbound then contact Calicut for the approach clearance for the approach to Rwy 10. Both the approach to RWY 28 and RW 10 start from over the CLC VOR. Where 90% of the weather always is. As clearly this was the situation on that night.
In September last year(2019) the Indian DGCA put out a notice that "When the Runway Visibility is less that 2000 metres that the runway will be closed for landings. However pilots can land at their Risk. So why didnt the Calicut ATC close the airport?
I personally have eaten alot of fire form my previous company for diverting to Cochin and TRV. because i in my judgment i felt that the attempt to land on RWY10 after considering the above mentioned issues with that runway in exactly the same weather was not worth it!.
I hope that the Minister of Transport and the Dir General of DGCA will make the necessary changes to reduce the risks for Indian passengers and crews!
This is a Sad Sad day for Indian Aviation!
Over the years the approach to RWY 10 has always been "problematic" because of its visual and environmental "characteristics". In the early days it was a visual approach only. Then they put a VOR approach, then with in the last few years because of the Indian Airports "modernization" the upgraded to an ILS RW10 approach. However the Approach minimums though lower. Have been off set by the fact that the Landing distance beyond the glideslope is less. Also the visual appearance on breakout gives the appearance of a twisted runway. And following the Glideslope to touchdown puts you 1000 Meters beyond the touchdown point. Which on a dry day with Autobrake 3 or max braking takes you to the end!!
The ATC facility at the Airfield either do not know or haven't received proper training on how to use the radar. And either are not willing to or for some unexplained reason cant give proper assistance to pilots during times of Monsoonal weather in the area.They relay on Cochin approach to give the clearance to intercept the final track inbound then contact Calicut for the approach clearance for the approach to Rwy 10. Both the approach to RWY 28 and RW 10 start from over the CLC VOR. Where 90% of the weather always is. As clearly this was the situation on that night.
In September last year(2019) the Indian DGCA put out a notice that "When the Runway Visibility is less that 2000 metres that the runway will be closed for landings. However pilots can land at their Risk. So why didnt the Calicut ATC close the airport?
I personally have eaten alot of fire form my previous company for diverting to Cochin and TRV. because i in my judgment i felt that the attempt to land on RWY10 after considering the above mentioned issues with that runway in exactly the same weather was not worth it!.
I hope that the Minister of Transport and the Dir General of DGCA will make the necessary changes to reduce the risks for Indian passengers and crews!
This is a Sad Sad day for Indian Aviation!
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The main problem with RW10 is tailwind landing in wet conditions. All things being what they are if the airline had forbidden tailwind landing on RW10 this accident would not have happened.
Re position of the throttles - anything is possible here as to why pedestal controls are in the position they are - it is possible that the separate of fuselage sections pulled the cables sufficiently to change throttle positions...
I don't think the aircraft "slid down the slope". There are no tell-tale tracks/ground damage* until much further down the slope. I think the aircraft "launched", not by much but enough to clear most of the slope in an arcing path until the tail hit pitching the nose down near/at the bottom of the slope.
Very sad, especially given the sense of deja-vu. A groundspeed of 176kts just prior to touchdown is significant no matter what wx conditions or runway contamination existed.
*there are two small indentations in what appears to be a "hedge-shaped" wall about half way down the slope - possible fuselage/left engine contact - hard to say.
Very sad, especially given the sense of deja-vu. A groundspeed of 176kts just prior to touchdown is significant no matter what wx conditions or runway contamination existed.
*there are two small indentations in what appears to be a "hedge-shaped" wall about half way down the slope - possible fuselage/left engine contact - hard to say.
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This guy has never seen a 737 upclose. "Boeing reduced the amount of flaps you can use for landing and takeoff when the 737 was stretched" Flaps 40 has been there since day 1 and unlike the 737-300/400/500, which can use 1 (not -400), 5 and 15 for takeoff, NG and MAX can also use 25.
A320, which is a much newer design that the 737, also proves very well that there's no problem having only four main gear wheels on a narrowbody aircraft even with much higher MTOWs than 737-800.
A320, which is a much newer design that the 737, also proves very well that there's no problem having only four main gear wheels on a narrowbody aircraft even with much higher MTOWs than 737-800.
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