Caribbean B738 at Georgetown on Jul 30, 2011, overran runway
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The Flight Safety Foundation published a great presentation that may be useful for some to understand the factors involved with this accident; it can be found on their website or at the following Smart Cockpit link:
SmartCockpit - Airline training guides, Aviation, Operations, Safety
There are a couple more that you may be interested in:
SmartCockpit - Airline training guides, Aviation, Operations, Safety
SmartCockpit - Airline training guides, Aviation, Operations, Safety
Just click on appropriate icon to open or download.
Cheers
SmartCockpit - Airline training guides, Aviation, Operations, Safety
There are a couple more that you may be interested in:
SmartCockpit - Airline training guides, Aviation, Operations, Safety
SmartCockpit - Airline training guides, Aviation, Operations, Safety
Just click on appropriate icon to open or download.
Cheers
Last edited by Che Guevara; 4th Aug 2011 at 20:03.
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No disrespect to injured pax but...
Just want to express sympathy for the captain - can't imagine what's going thru his mind now. Regardless of the circumstances/causes/outcome, it happened on his 'watch' and must be hard on any commander.
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Slf4
I have to agree with you there.
However, one of my problems after 31 years in the business is the lack of state of art letdown aids at some airports. Why doesn't the ILS work in Georgtown, why isn't there at least an RNAV approach there?
The Airlines are paying Landing Fees, so why not provide the facilities.
However, one of my problems after 31 years in the business is the lack of state of art letdown aids at some airports. Why doesn't the ILS work in Georgtown, why isn't there at least an RNAV approach there?
The Airlines are paying Landing Fees, so why not provide the facilities.
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The rudder position or the position of any other flight control surface with zero hydraulic pressure to the systems means nothing for obvious reasons.
Henri737
what "point" am i missing?
Read my lips, YOU CANNOT RETRACT THE LEADING EDGE DEVICES USING THE ALTERNATE FLAP SYSTEM.
The system will not do it either intentionally or otherwise.
severing the flap controls, commanding flaps-up on electric hydraulics with the flaplever in 40
Read my lips, YOU CANNOT RETRACT THE LEADING EDGE DEVICES USING THE ALTERNATE FLAP SYSTEM.
The system will not do it either intentionally or otherwise.
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The point is that he is not talking about alternate flaps at all, but rather the break-up of the fuselage disrupting the mechanical linkage to the flap hydraulic power unit to command flaps up. If the crew did not select flaps up well prior to the overrun, there is no other way they could have been retracted. There must have been enough residual pressure for retraction.
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An inadvertent selection of flaps up on landing roll maybe ? That would stow the spoilers and make stopping far more difficult.
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...
I've heard of spoiler blowdown on aircraft like 767's during overwing exit ops. Is this an option on the NG?
BobM2 Re-read his post. he said
The only Electric Hydraulic system on the 737 is the Alternate Flaps and these WILL NOT RETRACT THE LEADING EDGE DEVICES.
So, if the crash did cause the Alternate Flaps to run then ONLY the trailing edge devices would slowly retract using the Alternate and Electric Motor. But it is very slow, something like 3.5 minutes cycle time.
From the photos all the Flaps/Slats are fully retracted, the only way for this to occur is with normal HYD B power.
capish?
commanding flaps-up on electric hydraulics with the flaplever in 40
The only Electric Hydraulic system on the 737 is the Alternate Flaps and these WILL NOT RETRACT THE LEADING EDGE DEVICES.
So, if the crash did cause the Alternate Flaps to run then ONLY the trailing edge devices would slowly retract using the Alternate and Electric Motor. But it is very slow, something like 3.5 minutes cycle time.
From the photos all the Flaps/Slats are fully retracted, the only way for this to occur is with normal HYD B power.
capish?
Last edited by nitpicker330; 5th Aug 2011 at 04:37.
This quote from the 737NG Operating Manual regarding the Flap system:--
Flap and Slat Sequencing
LE devices and TE flaps are normally extended and retracted by hydraulic power from system B………………etc
Alternate Extension
In the event that hydraulic system B fails, an alternate method of extending the LE devices and extending and retracting the TE flaps is provided.
The TE flaps can be operated electrically through the use of two alternate flap switches. The guarded ALTERNATE FLAPS master switch closes a flap bypass valve to prevent hydraulic lock of the flap drive unit and arms the alternate flaps position switch. The ALTERNATE FLAPS position switch controls an electric motor that extends or retracts the TE flaps. The switch must be held in the DOWN position until the flaps reach the desired position. No asymmetry or skew protection is provided through the alternate (electrical) flap drive system.
When using alternate flap extension the LE flaps and slats are driven to the full extended position using power from the standby hydraulic system. In this case the ALTERNATE FLAPS master switch energizes the standby pump and the ALTERNATE FLAPS position switch, held in the down position momentarily, fully extends the LE devices.
Note: The LE devices cannot be retracted by the standby hydraulic system.
Flap and Slat Sequencing
LE devices and TE flaps are normally extended and retracted by hydraulic power from system B………………etc
Alternate Extension
In the event that hydraulic system B fails, an alternate method of extending the LE devices and extending and retracting the TE flaps is provided.
The TE flaps can be operated electrically through the use of two alternate flap switches. The guarded ALTERNATE FLAPS master switch closes a flap bypass valve to prevent hydraulic lock of the flap drive unit and arms the alternate flaps position switch. The ALTERNATE FLAPS position switch controls an electric motor that extends or retracts the TE flaps. The switch must be held in the DOWN position until the flaps reach the desired position. No asymmetry or skew protection is provided through the alternate (electrical) flap drive system.
When using alternate flap extension the LE flaps and slats are driven to the full extended position using power from the standby hydraulic system. In this case the ALTERNATE FLAPS master switch energizes the standby pump and the ALTERNATE FLAPS position switch, held in the down position momentarily, fully extends the LE devices.
Note: The LE devices cannot be retracted by the standby hydraulic system.
NSEU………….This is the Boeing 737NG PAX EVAC CHECKLIST:
The Flaps will not retract on any Boeing type, ever. The only thing is that on the 777-300 the inboard Spoilers retract to allow the Door 4 slide down the back of the wing. ( maybe on other types as well, but not the 737 )
737NG EVACUATION PROCEDURE
Both Captain and F/O complete their specific actions from RECALL (QRH Back Cover.2)
- Verify Flaps 40 (1) 1 - Verify parking brake set
- Select Speedbrake lever to down (2) - Engine start levers to CUT OFF
- Verify Flaps 40 - Select Pressurization Mode Selector to
Manual - Open the outflow valve (3) - Notify Tower (4)
(1) If time allows, verify that the flaps are 40 before the engine start levers are moved to CUTOFF.
(2) Speedbrakes are positioned down to prevent possible interference or injury to passengers evacuating through the overwing escape hatches
(3) Opening the outflow valve will ensure complete depressurization of the aircraft to allow opening of the escape hatches and doors.
(4) « MAYDAY MAYDAY MAYDAY XXX, EMERGENCY EVACUATION ON POSITION XXX »
2
Command evacuation with the PA:
«THIS IS AN EMERGENCY, EVACUATE THE AIRCRAFT USING ALL AVAILABLE EXITS » [called twice]
3
- Override and pull all ENGINE and APU fire switches
- Rotate and hold for 1 second engine or APU fire light which is illuminated
- Call « EVACUATION NON NORMAL CHECK-LIST »
- Take QRH and make ready EVACUATION check-list (5)
Time permitting, F/O reads the EVACUATION NNC. The Captain must respond to any items covered in his own areas of responsibility by repeating the response. The F/O will respond to any items which fall under his area of responsibility.
I.e. F/O reads: « PARKING BRAKE .... SET » Captain verifies and responds: «SET» When a pilot is incapacitated and an evacuation is necessary, the remaining pilot will take the QRH and execute each item.
4
After completion of the NNC the Captain will:
- Take a torch (and smoke hood if need be)
-Direct and assist passenger evacuation. Ensure all passengers and crew have evacuated the aircraft: using reasonable judgment and without undue danger, the Captain will check every row till the end of the cabin and assist immobilized passengers (if not yet done by the cabin crew), then evacuate using an aft exit
- Will assist passengers at the bottom of the left hand slides
After completion of the NNC the F/O will: - Take a torch (and smoke hood if need be) - Assist cabin crew as necessary to ensure
forward door(s) open and escape slide
activated. - Proceed to ground without delay. - Will assist passengers at the bottom of the
right hand slides
When a pilot is incapacitated and after completion of the NNC, the remaining pilot will ask cabin crew help to evacuate incapacitated pilot
The Flaps will not retract on any Boeing type, ever. The only thing is that on the 777-300 the inboard Spoilers retract to allow the Door 4 slide down the back of the wing. ( maybe on other types as well, but not the 737 )
737NG EVACUATION PROCEDURE
Both Captain and F/O complete their specific actions from RECALL (QRH Back Cover.2)
- Verify Flaps 40 (1) 1 - Verify parking brake set
- Select Speedbrake lever to down (2) - Engine start levers to CUT OFF
- Verify Flaps 40 - Select Pressurization Mode Selector to
Manual - Open the outflow valve (3) - Notify Tower (4)
(1) If time allows, verify that the flaps are 40 before the engine start levers are moved to CUTOFF.
(2) Speedbrakes are positioned down to prevent possible interference or injury to passengers evacuating through the overwing escape hatches
(3) Opening the outflow valve will ensure complete depressurization of the aircraft to allow opening of the escape hatches and doors.
(4) « MAYDAY MAYDAY MAYDAY XXX, EMERGENCY EVACUATION ON POSITION XXX »
2
Command evacuation with the PA:
«THIS IS AN EMERGENCY, EVACUATE THE AIRCRAFT USING ALL AVAILABLE EXITS » [called twice]
3
- Override and pull all ENGINE and APU fire switches
- Rotate and hold for 1 second engine or APU fire light which is illuminated
- Call « EVACUATION NON NORMAL CHECK-LIST »
- Take QRH and make ready EVACUATION check-list (5)
Time permitting, F/O reads the EVACUATION NNC. The Captain must respond to any items covered in his own areas of responsibility by repeating the response. The F/O will respond to any items which fall under his area of responsibility.
I.e. F/O reads: « PARKING BRAKE .... SET » Captain verifies and responds: «SET» When a pilot is incapacitated and an evacuation is necessary, the remaining pilot will take the QRH and execute each item.
4
After completion of the NNC the Captain will:
- Take a torch (and smoke hood if need be)
-Direct and assist passenger evacuation. Ensure all passengers and crew have evacuated the aircraft: using reasonable judgment and without undue danger, the Captain will check every row till the end of the cabin and assist immobilized passengers (if not yet done by the cabin crew), then evacuate using an aft exit
- Will assist passengers at the bottom of the left hand slides
After completion of the NNC the F/O will: - Take a torch (and smoke hood if need be) - Assist cabin crew as necessary to ensure
forward door(s) open and escape slide
activated. - Proceed to ground without delay. - Will assist passengers at the bottom of the
right hand slides
When a pilot is incapacitated and after completion of the NNC, the remaining pilot will ask cabin crew help to evacuate incapacitated pilot
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OK, for the last time:
1. let's wait for the official investigation results.
2. about the flaps: I know how they work after 16.000 hrs 732,733,734, 737 and 738. What we don't know is what will happen and what the flapsystem can do on electric hydraulic pumps (engine's stopped so no engine-hydraulics)with the flaplever in 40 and you break the fwd fuselage in half: do you know? You will not find it in your cockpit companion or FCOM or in any other publication.
So it is not possible to predict or draw conclusions about aircraftsystems in an accident. This might go very different than you would expect so don't draw conclusions, let's wait for the accidentinvestigators.
1. let's wait for the official investigation results.
2. about the flaps: I know how they work after 16.000 hrs 732,733,734, 737 and 738. What we don't know is what will happen and what the flapsystem can do on electric hydraulic pumps (engine's stopped so no engine-hydraulics)with the flaplever in 40 and you break the fwd fuselage in half: do you know? You will not find it in your cockpit companion or FCOM or in any other publication.
So it is not possible to predict or draw conclusions about aircraftsystems in an accident. This might go very different than you would expect so don't draw conclusions, let's wait for the accidentinvestigators.
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Henry,
At first I was going to respond dissing your post, but after some thought I see what you mean. We have no idea how the systems may have responded to short circuits, stretched cables and wot not during the accident. Any other possibility seems so unlikely that such an unusual configuration (look at the spoilers) would most probably be associated with the accident directly.
What we don't know is what will happen and what the flapsystem can do on electric hydraulic pumps (engine's stopped so no engine-hydraulics)with the flaplever in 40 and you break the fwd fuselage in half: do you know?
I'd be very interested to see how the Alternate Flaps fluid could pressurize actuators backwards through a system designed to run only one way even if the fuselage broke up!!
The fluid from the standby reservoir pressurizes a dedicated line TO the Leading Edges and CANNOT suck them back up!!
Anyway...............I agree we should wait for the official report.
The fluid from the standby reservoir pressurizes a dedicated line TO the Leading Edges and CANNOT suck them back up!!
Anyway...............I agree we should wait for the official report.
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When are you stupid theorists going to accept that the flaps were used in the normal manner, F40 on approach then retracted under braking during the landing run. This is normal practice to avoid FOD damage to the flaps while taxiing, especially at 3rd world strips where taxiways are narrow and often littered with debris.
The cause of the accident is obvious, they landed fast and deep on a short strip. Sloppy airmanship, it happens regularly with the same result.
Simple rule for short strips:- Approach at the correct speed and if the wheels are not on the ground at the piano keys GO AROUND.
The cause of the accident is obvious, they landed fast and deep on a short strip. Sloppy airmanship, it happens regularly with the same result.
Simple rule for short strips:- Approach at the correct speed and if the wheels are not on the ground at the piano keys GO AROUND.