Caribbean B738 at Georgetown on Jul 30, 2011, overran runway
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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.
Foreign object damage to flaps is a big problem at unmade airstrips where jets are unlikely to operate and pilots experienced in these conditions will have devoloped a habit of getting the flaps up as soon as reasonably practical to minimise the risk of damage.
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.
so flaps 30 is still more than adequate, and 40 being the best choice.
The s/e example is an emergency situation and therefore no factoring is required (as I am sure you know) .
Basically, by choosing Flap 30 (and I'm not saying this crew did), unless you select autobrake max your buffer for speed maintenance, threshold crossing height, touchdown point, float in the flare, tailwind etc is only 370m. Not enough in my opinion when simply selecting Flap 40 brings you an extra 200m of buffer. Of course it can be done at flap 30, but why would you?
If you applied max braking you could stop in 1000m....but why would you?
stack the deck in your favour and make sound choices, Flap 30 is not a sound choice on a runway 2200m long unless gusts are a factor IMO.
The objective on normal concrete or tarmac runways is to have the flaps stowed before turning onto a narrow taxiway where the engines may overhang the edges and foreign objects may be blown up, damaging the flaps.
In that scenario I would be briefing it before leaving cruise altitude and below 15kts before making the selection. But maybe that is because I have the luxury of operating into better strips and I don't understand how common it is to have taxiways like that as part of the route structure.
after speaking with a colleague at this airline in question this is also their SOP.
Framer
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Lift / Drag
Thanks Westhawk on review you are correct. I was actually thinking of an aborted takeoff where the procedure is to extend the flaps to 40 after decelerating thru 60 knots and if done to soon at higher speeds, the flaps going from a takeoff posistion of 5 to 40 would increase lift and adversely affect braking. I must start posting in the day and not at 4 am.
extending flaps further to 40 during a reject????
Who's SOP is that - its sure as heck not Boeings.
Who's SOP is that - its sure as heck not Boeings.
Dingy737, you also stated;
The aircraft was properly configured for a 30 flap landing!!! 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. Beleive it!
For me that would explain your in depth knowledge of the cable tension and also why you were emphatic that the crew used flap 30 very shortly the crash.
I understand if you would rather keep that information to yourself, just thought I'd ask in case you don't mind revealing how you know these things.
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Rejected Takeoff
As I remeber it for the 737 during an abort
F/O call 60 kts decelerating
Stop assured:
Captain:Reverse thrust to idle by taxi speed.
F/o: Lowers flaps to 40 degrees
The thinking was to have the flaps in the evacuation posistion in anticipation the abort may lead to an evac. I am not uptodate wasnt aware it was changed. but i do remember some f/o's being overly anxious to complete their drill and running the flaps to 40 while still above 60 kts and yes the evacuation drill call for the F/O to select flaps to 40 which would have already been done.
I have lots of friends in the region and i am just sharing the info i consider credible, currently in the sand.
F/O call 60 kts decelerating
Stop assured:
Captain:Reverse thrust to idle by taxi speed.
F/o: Lowers flaps to 40 degrees
The thinking was to have the flaps in the evacuation posistion in anticipation the abort may lead to an evac. I am not uptodate wasnt aware it was changed. but i do remember some f/o's being overly anxious to complete their drill and running the flaps to 40 while still above 60 kts and yes the evacuation drill call for the F/O to select flaps to 40 which would have already been done.
I have lots of friends in the region and i am just sharing the info i consider credible, currently in the sand.
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Dingy....
Sorry mate I think your confused... unless your company (which one was that) deviated from recommended boeing SOP and created your own.
The rejected takeoff drill says nothing of lowering flaps...in fact increasing flaps may even take more weight off the wheels and further inhibit braking.... as you recall at speeds less that 100kts the reverse thrust is less useful than the brakes.
The EVAC drill which is completely separate has the captain lower flaps to 40 to assist with over the wing egress..
Which model 37 are you referring to cause I've flown the classics and the NGs and neither have ever had anything your referring to.
I gotta call BS on your claim - either that or your memory is very incorrect.
WJP
Sorry mate I think your confused... unless your company (which one was that) deviated from recommended boeing SOP and created your own.
The rejected takeoff drill says nothing of lowering flaps...in fact increasing flaps may even take more weight off the wheels and further inhibit braking.... as you recall at speeds less that 100kts the reverse thrust is less useful than the brakes.
The EVAC drill which is completely separate has the captain lower flaps to 40 to assist with over the wing egress..
Which model 37 are you referring to cause I've flown the classics and the NGs and neither have ever had anything your referring to.
I gotta call BS on your claim - either that or your memory is very incorrect.
WJP
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Boeing procedures
A 737 can come with hundeds of options all dependant on the operator.
While flying as a passenger on a Delta 738 I observed the de/anti icing procedure take place with the slats and flaps set for takeoff, on competion they were retracted for taxi. I asked the Captain about it and his reply was after the merger with northwest they adopted this procedure to have conformity acrooss the merger. I know several operators that still de-ice with flaps/slats retracted. So my question is, can an operator have its own procedure as long as Boeing sactions it?
The answer would have to be yes.
And if so what then are Boeing procedures? What you know as boeing procedures may just be your operators choice of options on a boeing aircraft.
While flying as a passenger on a Delta 738 I observed the de/anti icing procedure take place with the slats and flaps set for takeoff, on competion they were retracted for taxi. I asked the Captain about it and his reply was after the merger with northwest they adopted this procedure to have conformity acrooss the merger. I know several operators that still de-ice with flaps/slats retracted. So my question is, can an operator have its own procedure as long as Boeing sactions it?
The answer would have to be yes.
And if so what then are Boeing procedures? What you know as boeing procedures may just be your operators choice of options on a boeing aircraft.
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Smartcockpit
WJP the smartcockpit web site for B737NG-briefings displays the Ryanair RTO procedures which conflicts with yours, which require the Captain to select flaps to 40. Their procedure is to have the F/O do it.
Which is Boeings and how would you know? It is clear operators can make changes to boeings procedures. The procedure I quoted was for the F/O to run flaps to 40 when below 60 knots and stopping assured, I think the focus here is on stopping assured as in decelerating below 20 knots with 5000 feet of runway left , it was the crews call and the operators procedure not mine.
Which is Boeings and how would you know? It is clear operators can make changes to boeings procedures. The procedure I quoted was for the F/O to run flaps to 40 when below 60 knots and stopping assured, I think the focus here is on stopping assured as in decelerating below 20 knots with 5000 feet of runway left , it was the crews call and the operators procedure not mine.
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our sops as well call for F/O to
-note reject speed
-Monitor braking speed brakes and reverse
-through 60 knots select flaps 40
and depressurize the Aircraft.
These I believe are closely worded to Boeing SOPs to keep things standard
for a Boeing 738 or NG
My two cents .
-note reject speed
-Monitor braking speed brakes and reverse
-through 60 knots select flaps 40
and depressurize the Aircraft.
These I believe are closely worded to Boeing SOPs to keep things standard
for a Boeing 738 or NG
My two cents .
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llnfder what company is that may i ask.
The Boeing issued flight crew training manual for the 737-6,7,8,9 and BBJ
does not allude anywhere to the flaps being lowered during a reject...
why would you depresssurize the aircraft for a simple reject NOT leading to an evac?
Regards
WJP
The Boeing issued flight crew training manual for the 737-6,7,8,9 and BBJ
does not allude anywhere to the flaps being lowered during a reject...
why would you depresssurize the aircraft for a simple reject NOT leading to an evac?
Regards
WJP
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RTO
I beleive procedures are created from lessons learnt in previous incidents. Time is of the essence in most emergencies, rather than have several different rto drills why not have one that covers the worse case, its just being proactive and erring on the safe side. The 738 pressurizes the cabin on the take off roll, for passenger comfort. The drill as i knew it did involve selecting the outflow valve to manual and holding it until open to make sure their was no pressure differential. If the abort escalated to an evac. you would be well ahead of the game, if it did not no harm caused.
I was hoping that someone could post a Boeing offical link if it exist.
As for boeing manuals all operators will have Boeing issued manuals, with boeing printed on every page, the text and procedures will differ amongst operator as we have established.
I was hoping that someone could post a Boeing offical link if it exist.
As for boeing manuals all operators will have Boeing issued manuals, with boeing printed on every page, the text and procedures will differ amongst operator as we have established.
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@ GYS
BTW do they use FCOM's in South America?
The landing distance figures have been mentioned by a few people here, but I recall those are factored without the use of thrust reverser. So you would still have a slightly bigger margin in terms of distance before departing the runway, right?
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The Boeing issued flight crew training manual for the 737-6,7,8,9 and BBJ does not allude anywhere to the flaps being lowered during a reject...
I just took a look at the Smartcockit stuff. The Ryanair reject manouvre alludes the outdated procedure of the FO flap 40 recall item on the old Boeing evac checklist. It is dated 2008 when the standard SOPs changed and maybe Ryanair have also amended their procedure since then?
Last edited by Sciolistes; 17th Aug 2011 at 05:32.
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Ya lost all street credit when you used RYAN AIR as your example.
The drill to depressurize the cabin and lower flaps in all rejects is absurd...
but a point that will be lost by trying to argue the point.
The majority if not more than 90% of all rejects have nothing to do with requiring an evac.
But it doesn't matter either way... Ill never work for Ryan Air and won't have to worry about it.
Off to maui for the week enjoy chaps..
WJP
The drill to depressurize the cabin and lower flaps in all rejects is absurd...
but a point that will be lost by trying to argue the point.
The majority if not more than 90% of all rejects have nothing to do with requiring an evac.
But it doesn't matter either way... Ill never work for Ryan Air and won't have to worry about it.
Off to maui for the week enjoy chaps..
WJP
WJApilot I think you are the one losing street cred. making posts like your last one. Ryanair (not RYAN AIR) successfully operates around three times as many 737s as Westjet if that is who you work for. Those who have flown the 737 a bit longer remember various old procedures. Hopefully with experience SOPs are improved and we can lessen the risk of having our mistakes disected on PPRuNe including at least three recent landing accidents at night with the NG in central america / carribbean.
