BA056 JNB-LHR Incident.
Join Date: May 2009
Location: uk
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Ladies &/or gentlemen, there's a part of this story I've not seen mentioned here yet that happened after the initial emergency was over and the aircraft was safely up in the air.
I'm not prepared to say owt yet until I'm sure I won't be dropping someone in deep poo, but do keep an ear out for something that took place before the aircraft landed again.
As an aside, it's nice to see that you professionals can bitch and snipe at each other the same way members of music, photography and motorcycle forums do.
Cheers all,
A fare paying passenger.
I'm not prepared to say owt yet until I'm sure I won't be dropping someone in deep poo, but do keep an ear out for something that took place before the aircraft landed again.
As an aside, it's nice to see that you professionals can bitch and snipe at each other the same way members of music, photography and motorcycle forums do.
Cheers all,
A fare paying passenger.
Join Date: Apr 2005
Location: UK
Posts: 459
Likes: 0
Received 0 Likes
on
0 Posts
A wild guess to i sit in the back on your 1st post, aircraft headed for London as is normal on that route, after some time, Joburg was selected as next landing, fuel was off loaded during flight, aircraft then landed back at Joburg, appears a great job was done by all.
But if you know different, please tell !
But if you know different, please tell !
Join Date: Apr 2008
Location: London
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
I see an Emergency AD coming out as a result of this. From all the posts looks like the aircraft did as designed. Well of course except for it happening in the wrong flight phase!
I appreciate also the reason behind the thrust rev amber indication needs to be fully investigated but the config change to the aircraft is the more pressing issue.
I would imagine a interim measure which would call for the deactivation of the auto flap function for the LEDs then in future a modification that would incorporate throttle lever position into the logic that the FCUs use for the auto flap function. But both of these would take some time to produce the necessary Service Bulletins.
As an engineer I could see a short term fix to prevent the change in config that this aircraft suffered from and that would be to arm the alternate flaps during the take off roll. Then once in the air deselect and operate the flaps normally.
I appreciate also the reason behind the thrust rev amber indication needs to be fully investigated but the config change to the aircraft is the more pressing issue.
I would imagine a interim measure which would call for the deactivation of the auto flap function for the LEDs then in future a modification that would incorporate throttle lever position into the logic that the FCUs use for the auto flap function. But both of these would take some time to produce the necessary Service Bulletins.
As an engineer I could see a short term fix to prevent the change in config that this aircraft suffered from and that would be to arm the alternate flaps during the take off roll. Then once in the air deselect and operate the flaps normally.
Just another number
Join Date: Jun 2001
Location: UK
Age: 76
Posts: 1,077
Likes: 0
Received 0 Likes
on
0 Posts
jimpy
Would it be possible to programme the FCUs so that the auto function of the LEDs is only active when either flap 25 or 30 is selected?
Dave
Would it be possible to programme the FCUs so that the auto function of the LEDs is only active when either flap 25 or 30 is selected?
Dave
Any chance you could tell "I sit in the back" that he has failed his probation on the grounds of being ludicrous and ban him.
Join Date: Feb 2008
Location: Europe
Age: 48
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
B747-200 OA411 - Gear retraction during stall
Regarding the issue of the drag effect of the landing gear doors opening up during gear reatraction, I think that many people are unaware of this old, very similar, incident of Olympic Airways back in the 70s with the 747 classic.
On 12-8-1978 the OA411 flights from Athens Hellinicon (LGAT) airport experienced an engine flameout (engine two) during takeoff (at v1).
Additionally even though the takeoff procedure included the use of "water methanol injection" providing additional thrust during the very hot Athens august afternoon, due to cockpit miscommunication, the flight engineer turned off the injection just around V1.
The airplane eventually took off at Vr at the end of the runway just barely managing to pass the first hill (209ft) at 215ft (climb rate less than 200ft/min). During climb, engine 3, also suffered damage and become inoperational.
Under pilot's orders, the landing gear was not retracted due to the fear of drag from the huge landing gear doors opening. This was against company SOPs.
He continued on a level flight aiming for the nearest uninhabited hill near Piraeus but the flight engineer did manage to get a bit more power, thus increasing IAS and letting him reach the sea where he began dumping fuel and eventually retracting the landing gears performing a successful go-around.
Boeing did run the scenario many times in simulators all resulting in a crash ...
On 12-8-1978 the OA411 flights from Athens Hellinicon (LGAT) airport experienced an engine flameout (engine two) during takeoff (at v1).
Additionally even though the takeoff procedure included the use of "water methanol injection" providing additional thrust during the very hot Athens august afternoon, due to cockpit miscommunication, the flight engineer turned off the injection just around V1.
The airplane eventually took off at Vr at the end of the runway just barely managing to pass the first hill (209ft) at 215ft (climb rate less than 200ft/min). During climb, engine 3, also suffered damage and become inoperational.
Under pilot's orders, the landing gear was not retracted due to the fear of drag from the huge landing gear doors opening. This was against company SOPs.
He continued on a level flight aiming for the nearest uninhabited hill near Piraeus but the flight engineer did manage to get a bit more power, thus increasing IAS and letting him reach the sea where he began dumping fuel and eventually retracting the landing gears performing a successful go-around.
Boeing did run the scenario many times in simulators all resulting in a crash ...
Join Date: Feb 2004
Location: Australia
Posts: 1,307
Likes: 0
Received 0 Likes
on
0 Posts
If memory serves me correctly, it was British Airways which was involved in a similar incident many years ago.
A foreign object (manual?) had been left just forward of the thrust quadrant prior to departure. When the TOGA switches were pushed, the thrust levers advanced and the reverser knobs struck the object pushing them upwards.
There is a mechanical interlock which prevents the reverse levers moving upwards to reverse idle with the forward thrust levers more than a few degrees from idle. However, the reverse levers do move upwards a little bit (6 degrees or so). This is enough to trigger the first set of switches for reverser activation (and the LE flaps). Or rather, it used to be. An Airworthiness Directive and an associated Service Bulletin (SB 747-27A2356) was raised to modify/change some components to make the activation of this first switch set occur at 10 or so degrees rather than 6 degrees. The reverser levers will not physically move to 10 degrees with the forward levers out of idle.
Can't find the link I was looking for, but the following is related to this incident:
Airworthiness directives: Boeing, - Federal Register, November 25, 1998 (Nbr. Vol. 63, No. 227) - vLex
Rgds.
NSEU
A foreign object (manual?) had been left just forward of the thrust quadrant prior to departure. When the TOGA switches were pushed, the thrust levers advanced and the reverser knobs struck the object pushing them upwards.
There is a mechanical interlock which prevents the reverse levers moving upwards to reverse idle with the forward thrust levers more than a few degrees from idle. However, the reverse levers do move upwards a little bit (6 degrees or so). This is enough to trigger the first set of switches for reverser activation (and the LE flaps). Or rather, it used to be. An Airworthiness Directive and an associated Service Bulletin (SB 747-27A2356) was raised to modify/change some components to make the activation of this first switch set occur at 10 or so degrees rather than 6 degrees. The reverser levers will not physically move to 10 degrees with the forward levers out of idle.
Can't find the link I was looking for, but the following is related to this incident:
Airworthiness directives: Boeing, - Federal Register, November 25, 1998 (Nbr. Vol. 63, No. 227) - vLex
Rgds.
NSEU
Last edited by NSEU; 22nd May 2009 at 03:50.
Join Date: Oct 1999
Location: UK
Age: 70
Posts: 288
Likes: 0
Received 0 Likes
on
0 Posts
KISS
Instead of adding further complexity to the system why not just lock out the L/E auto-retract feature? It's there to prevent FOD on landing... how often does that happen in real life and how does that risk compare to what we have just witnessed in terms of likelihood and consequence? Of course it would mean someone actually getting off their bum and doing a PROPER walk round prior to the next departure....
Pinkman
Pinkman
Old Aero Guy
That makes a lot more sense than FOD. Seeing as it's pretty rare to have enough reverse efflux to lift an object as high as a LE slat except in the rarest of conditions.
FOD isn't the primary reason for LE retraction with reverse thrust. The main concern is fatigue due to exhaust impingment on the LE while in reverse.
Join Date: Apr 2009
Location: Petaluma
Posts: 330
Likes: 0
Received 0 Likes
on
0 Posts
The way I see it, LE slats are lift enhancers. If Reverse is selected, I think extra lift might be unnecessary, even counter productive. Stowing all lift enhancers seems a reasonable thing to do when your goal is to slow down. Leaving drag devices deployed likewise seems correct. (Flaps and spoilers).
Join Date: Mar 2001
Posts: 315
Likes: 0
Received 0 Likes
on
0 Posts
Imagine the scenario -
On rotation you get the stick shaker and two amber R's (inidcating you have two unlocked reversers).
The crew dont know the inboard and midspan LE devices have retracted ..
It would be extreemly tempting to assume the amber R symbols above the EPR are the problem and call for an engine shutdown ...
The crew did extreemly well ...
On rotation you get the stick shaker and two amber R's (inidcating you have two unlocked reversers).
The crew dont know the inboard and midspan LE devices have retracted ..
It would be extreemly tempting to assume the amber R symbols above the EPR are the problem and call for an engine shutdown ...
The crew did extreemly well ...
Join Date: Jul 2002
Location: On a park bench near an airport
Posts: 156
Likes: 0
Received 0 Likes
on
0 Posts
The way I see it, LE slats are lift enhancers. If Reverse is selected, I think extra lift might be unnecessary, even counter productive. Stowing all lift enhancers seems a reasonable thing to do when your goal is to slow down. Leaving drag devices deployed likewise seems correct. (Flaps and spoilers).
Imagine the scenario -
On rotation you get the stick shaker and two amber R's (inidcating you have two unlocked reversers).
The crew dont know the inboard and midspan LE devices have retracted ..
It would be extreemly tempting to assume the amber R symbols above the EPR are the problem and call for an engine shutdown ...
On rotation you get the stick shaker and two amber R's (inidcating you have two unlocked reversers).
The crew dont know the inboard and midspan LE devices have retracted ..
It would be extreemly tempting to assume the amber R symbols above the EPR are the problem and call for an engine shutdown ...
Join Date: Jan 2008
Location: Herts, UK
Posts: 748
Likes: 0
Received 0 Likes
on
0 Posts
The way I see it, LE slats are lift enhancers.
Not in the way that TE flaps are.
They principally extend the lift-curve-slope to higher incidences, but in themselves (at a given incidence) make little difference to lift
Thus at any given incidence, ground incidence in this case, as said, their retraction would make no appreciable difference
Join Date: Apr 2009
Location: Petaluma
Posts: 330
Likes: 0
Received 0 Likes
on
0 Posts
Boeing 727, Cleveland, crew forgets LE slats on T/O, all dead. No difference?
The shaker on this recent T/O? Explain.
The shaker on this recent T/O? Explain.
Last edited by Will Fraser; 25th May 2009 at 01:43.
Join Date: Jan 2008
Location: Herts, UK
Posts: 748
Likes: 0
Received 0 Likes
on
0 Posts
Will
Please read what I said carefully... !
AT A GIVEN INCIDENCE
To get the extra lift you have to increase incidence - beyond the max (or stall) incidence without them.. not the case with TE devices
So in themsleves they don't increase lift, but allow for higher incidences without flow breakdown.
The stick-shaker will vary with incidence, depending on the LE device position
Take the Barajas incident... the pilot pulled a (wing) incidence at rotation taking the aircraft into the regime requiring LE slats. They were not deployed -> stick-shaker -> without reduction in incidence -> approach to stall, loss of directional control -> stall. Maybe, if he had taken a less aggressive approach, possibly, he could have fown it off on the shaker, rather than way above. It was the extreme incidence requiring LE devices, that ensured loss of control, not loss or lack of lift per se.
Perhaps a graph showing the effect of flaps and that of LE devices will make it clearer.. a picture is worth a thousand words.
..but its late, my eyes hurt and its time for beddy byes. Ask and it shall be given (later)....
Please read what I said carefully... !
AT A GIVEN INCIDENCE
To get the extra lift you have to increase incidence - beyond the max (or stall) incidence without them.. not the case with TE devices
So in themsleves they don't increase lift, but allow for higher incidences without flow breakdown.
The stick-shaker will vary with incidence, depending on the LE device position
Take the Barajas incident... the pilot pulled a (wing) incidence at rotation taking the aircraft into the regime requiring LE slats. They were not deployed -> stick-shaker -> without reduction in incidence -> approach to stall, loss of directional control -> stall. Maybe, if he had taken a less aggressive approach, possibly, he could have fown it off on the shaker, rather than way above. It was the extreme incidence requiring LE devices, that ensured loss of control, not loss or lack of lift per se.
Perhaps a graph showing the effect of flaps and that of LE devices will make it clearer.. a picture is worth a thousand words.
..but its late, my eyes hurt and its time for beddy byes. Ask and it shall be given (later)....
Last edited by HarryMann; 25th May 2009 at 02:00.
Join Date: Apr 2009
Location: Petaluma
Posts: 330
Likes: 0
Received 0 Likes
on
0 Posts
My point being that altering a wing's camber on T/O will cause havoc if not done with care. I agree with all your points. Slats do ennable Lift, is what I'm sayin. I see it as raising the wing, but effectively lowering the leading edge, creating a stubby high camber high lift wing at a speed the a/c could not otherwise fly at. Are you saying the slats ennable an effective lowering of Incidence, cause that's what I'm saying.