Caribbean B738 at Georgetown on Jul 30, 2011, overran runway
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It takes at least 30 seconds (closer to 35) to retract B738 flaps from 30 to up. That is with two engines at idle, two engine driven hydraulic pumps, two electric hydraulic pumps and an intact aircraft.
I guess all will be revealed.
I guess all will be revealed.
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Properly configured for 30 flap
Dc-Ate, I agree that 40 flap would be my choice, but both 30 and 40 flap settings can accomplish the job safely with out any fuss. The point here was focused on earlier speculation about whether the were extended at all and the adjective "properly" configured was an attempt to convey that the aircraft flaps and slats were in a landing configuration at touch down as opposed to retracted at touched down or even extended for touch down then hurridely retracted for all types of posted theories.
IF it is pilot error what would interest me is why an experienced Captain could make such an error. Fatigue for instance?
why an experienced Captain could make such an error.
Or going around at 500' if not stable...... or, if you've not touched down by the end of the touchdown zone/markings...GO AROUND.
Senior airline management need to be responsible for the cultivation of a culture in which this is the norm and deviating from it is seen as poor airmanship.
i saw 2 Caribbean airlines 738 vacating rwy there. both times, i was paying attention on the flap setting before and while they were vacating the rwy. and ofcourse, both times these were fully retracted before even getting to the runway end.
After impact the cable from the flap handle to actuator, did not break, but was under 7 times normal tension due to the bent fuselage, this resulted in an up selection to the actuator, somehow there was enough residual Hyd. psi to retract them.
Maybe there was a problem with flaps, maybe it was not going to full 40. so the crew may have attempted to cycle it without success and in the confusion while on final approach may have inadvertently left the lever in the "UP" position with the flaps stuck partially extended. On short final the flap may have slowly started to follow the lever position (UP). This may not have been realised and the pilot (unknowingly) compensated by adding more power to maintain his speed, or the auto thrust system automatically doing so. This would explain the assumed somewhat long and fast landing
touched down only about half way down the runway abeam the terminal building with about 3000 feet of runway remaining.
As to the lack of flaps/slats.....perhaps that particular Captain retracted them at touchdown on short runways to dump the lift and, supposedly help with the stopping. Just a thought. I never did that but it WILL work.
A FA friend mentioned, on B738s, once the emergency evacuation is activated,the flaps will retract to allow pax to use the overwing exits as an evacuation area...
There are some posts on this thread that scare me a bit if they are made by airline pilots. Hopefully they are just teenage kids who love Microsoft FS and enjoy pretending to know things on this forum.
At the end of the day a combination of solid SOP's and the flight discipline to follow them and this over run would never have ocurred.
Framer
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once the a/c is on ground with reversers deployed,there is no question of trying to get airborne again.look what happened to AI Express at Mangalore.
I s there any talk about where the a/c touched down in this case?
Flaps 30 is good enough for a 7000ft rwy...its good enough for 6000ft even if its wet with good braking action....no sweat.
I s there any talk about where the a/c touched down in this case?
Flaps 30 is good enough for a 7000ft rwy...its good enough for 6000ft even if its wet with good braking action....no sweat.
Per Ardua ad Astraeus
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The only 'fly in the ointment' for Dingy737 (#162) is that (OK, it did come from the WSJ, that fount of all that is knowledgeable and right) the flap lever was reportedly found in the up detent in the wreckage. That certainly is one heck of an 'up selection to the actuator'
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Finding the flap handle in the landing detent is inconclusive. If they ran the evacuation checklist the flaps would have been placed in the flap 40 detent. We will know soon enough where the flaps were or were not during the roll out. Speculation at this time is only that, speculation.
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The Aerogal video in youtube shows normal landing with landing flaps maybe 30 to 40 in the last seconds. Title of video is misleading too - nothing scary about it.
On the -200 we used to extend flaps from 30 to 40 after landing sometimes to help with the drag. Felt effective. I had never heard of retracting flaps while on landing roll until pprune...
On the -200 we used to extend flaps from 30 to 40 after landing sometimes to help with the drag. Felt effective. I had never heard of retracting flaps while on landing roll until pprune...
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nothing scary about it.
I had never heard of retracting flaps while on landing roll until pprune...
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Sorry cannot quote. Scary is relative. If you want scary extend the speedbrakes a few degrees to stop the float (not recommended). Of course I am certain nobody has done this, or landed with the flap load relief operating. These things never happen to us, only others far far away.
PPL? Too old to remember, however I seem to remember a discussion about instead of retracting the flaps after landing some people retracted the gear instead. Maybe that was the reason they didn't teach that.
PPL? Too old to remember, however I seem to remember a discussion about instead of retracting the flaps after landing some people retracted the gear instead. Maybe that was the reason they didn't teach that.
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"On the -200 we used to extend flaps from 30 to 40 after landing sometimes to help with the drag. Felt effective."
No where to find in the Boeing 737-200 FCOM or FCTM.
Time for a serious talk with the chief-pilot.....
No where to find in the Boeing 737-200 FCOM or FCTM.
Time for a serious talk with the chief-pilot.....
Of course I am certain nobody has done this, or landed with the flap load relief operating. These things never happen to us, only others far far away.
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gotofly -
Is there any talk about where the a/c touched down in this case?
Flaps 30 is good enough for a 7000ft rwy...its good enough for 6000ft even if its wet with good braking action....no sweat.
-----------------------------------------------------------------------
Non pilot eyewitnesses reported a long landing.
My perfromance charts say, even with Flaps 40, that 6000' will have weight restrictions if wet.
1500 hrs in the 737NG, most guys use 7000', or perhaps slightly, more runway, as the switch from Flaps 30 to Flaps 40.Wet runway and the switch is made for longer runways. Landing distance is part of the decision, the more critical factor is the reduced tendency to float with Flaps 40.
Is there any talk about where the a/c touched down in this case?
Flaps 30 is good enough for a 7000ft rwy...its good enough for 6000ft even if its wet with good braking action....no sweat.
-----------------------------------------------------------------------
Non pilot eyewitnesses reported a long landing.
My perfromance charts say, even with Flaps 40, that 6000' will have weight restrictions if wet.
1500 hrs in the 737NG, most guys use 7000', or perhaps slightly, more runway, as the switch from Flaps 30 to Flaps 40.Wet runway and the switch is made for longer runways. Landing distance is part of the decision, the more critical factor is the reduced tendency to float with Flaps 40.
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ref Aerogal
I counted about a 12 second float, during which he added more flaps.
BTW do they use FCOM's in South America?
Flaps 30 is good enough for a 7000ft rwy...its good enough for 6000ft even if its wet with good braking action....no sweat.
What if it was a 3 kt tail instead of nil wind? That increases all the distances by about 100m. Nah, Flap 30 in this situation would be a poor choice if you had no wind and were heavy.
Even Flap 40 AB2 will stop you only 30m short of the grass at MLW and put you 70m off the end if you have a 3kt tailwind.
My point? This needed to be a Flap 40 landing with AB3 as a minimum which will stop the aircraft in 1700m if everything goes well, it leaves you with about 500m for unforseen things like
1/ not crossing the threshold at exactly 50'
2/ not being exactly on speed
3/ not executing the perfect flare and touchdown
4/ the reported nil wind actually being a slight tailwind.
For all I know this crew did use Flap 40 and appropriate braking, but to say that Flap 30 is 'no sweat' is to ignore variables that you have limited control over, and to bank on everything going as planned.
PS all the above figures are derived from my books and the aircraft they apply to have 'short field performance'. I don't know if the accident aircraft did as well.
At max landing weight the aircraft legally requires a strip length of 1620m dry or 1860m wet (nil wind, standard day etc). If it's not short field performance then it'l need a fraction more.
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Emergency return
Question: If you depart from a 7400 ft runway at max Landing weight and loose an engine in a 737-800 can you return to land at that field.
The VREF speeds for max landing weight are aprox.,
Flaps 40= 142. Faps 30= 150 Flaps 15 = 158
The Boeing procedure for a single engine landing is to use flap 15. The Boeing Advisory landing distance for flap 15 one eng. inop. on a wet runway= 4888 feet, using max manual braking and max operative reverse thrust and of course touching down at the 1000 foot point.
I know of 2 such return to land events at that field at flaps 15 eng. out, still with no fuss, so flaps 30 is still more than adequate, and 40 being the best choice. So using flaps 30 are not to blame here.
Also the Boeing after landing procedure kicks in when clear of the runway which is when the flaps would be retracted, after speaking with a colleague at this airline in question this is also their SOP.
I do not understand this procedure of retracting flaps on the landing roll as they will transistion from the gratest drag posistion to the greatest lift posistion on its way to a fully stowed posistion and adversely affect the weight on wheels for proper braking.
The VREF speeds for max landing weight are aprox.,
Flaps 40= 142. Faps 30= 150 Flaps 15 = 158
The Boeing procedure for a single engine landing is to use flap 15. The Boeing Advisory landing distance for flap 15 one eng. inop. on a wet runway= 4888 feet, using max manual braking and max operative reverse thrust and of course touching down at the 1000 foot point.
I know of 2 such return to land events at that field at flaps 15 eng. out, still with no fuss, so flaps 30 is still more than adequate, and 40 being the best choice. So using flaps 30 are not to blame here.
Also the Boeing after landing procedure kicks in when clear of the runway which is when the flaps would be retracted, after speaking with a colleague at this airline in question this is also their SOP.
I do not understand this procedure of retracting flaps on the landing roll as they will transistion from the gratest drag posistion to the greatest lift posistion on its way to a fully stowed posistion and adversely affect the weight on wheels for proper braking.
I do not understand this procedure of retracting flaps on the landing roll as they will transistion from the gratest drag posistion to the greatest lift posistion on its way to a fully stowed posistion and adversely affect the weight on wheels for proper braking.
While full flaps produces more drag, more lift per unit of airspeed is produced as well. Note the lower Vref speeds associated with increased flaps setting. On jet transports, ground spoilers increase the weight on wheels and produce additional drag. This is far more effective at dumping lift than retracting flaps and adds drag instead of reducing it.
Retraction of flaps during the landing roll reduces the amount of lift produced at any given airspeed, thus increasing weight on wheels. It is an accepted and even manufacturer recommended technique to reduce landing roll distance on some light aircraft. Especially handy in bush flying.
I'm not aware of any jet transport aircraft where flap retraction during the landing roll is a recommended or approved action though. Ground spoilers are far more effective anyway and the danger of inadvertently selecting gear up instead of flaps up is mostly eliminated.