Easyjet B737 pitch-down incident 12 January
The commander rolled the wings level and attempted to arrest the rate of descent which had increased considerably, peaking at 21,000 fpm; the aircraft had pitched 30° nose down after the aircraft had been rolled to the left.
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I believe this is the second time this has happened to an EJ aircraft.Last time was 4-5 years ago on airtest out of a heavy maintenance facility in France post C check.I understand that reinstating the hydraulics without off loading the stabiliser/elevators by banking could lead to loss of the control surfaces.Huge well done to the crew.
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Maybe I need to get back in the sim and practice, but I don't see that you are doing yourself any favours in terms of further airspeed increase by rolling to 91 degree of bank in preference to just momentarily releasing the controls and re-instating the hydraulics at that point. Maybe more chance of your colleague re-instating the switches promptly as his eyes might be open rather than closed at the sight of a 91 degree bank angle via Boeings " letter-box".
I guess in theory the bank angle "should" help contain it, but the time spent rolling & then unrolling the aircraft might be better spent just promptly unloading/reinstating HYD power ASAP ? Just my feeling.
Tough old Bird the 737
440 . . . Vmo plus 100 phew 
I guess in theory the bank angle "should" help contain it, but the time spent rolling & then unrolling the aircraft might be better spent just promptly unloading/reinstating HYD power ASAP ? Just my feeling.
Tough old Bird the 737
440 . . . Vmo plus 100 phew
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Originally Posted by OneOffDave
With typical restraint, the local press here have covered the story in today's paper as "Airliner in terror plunge over Norfolk".
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The 90 degree bank manoeuvre is in the CAA test flight guidelines. The NG QRH seems to agree with that for a pitch up attitude (see Upset Recovery), but definitely not for pitch down. The main concern when turning the hydraulics back on is to have your hands off the controls to avoid overstressing the surfaces and linkages when the pressure comes back. The 90 degree bank has more to do with regaining airspeed (as opposed to trying to offload the wings). So the CAA's guideline to apply that bank in the case of any loss of control during manual reversion seems questionable.
What saved their lives was the airspeed increasing to a point that they had enough elevator authority to pull up. The captain was not aware that the hydraulics were not back on...
A lot to be learned from that incident.
P
It was a 'favour' that probably saved their lives - I don't think they had the altitude to offload the controls again . . .
A lot to be learned from that incident.
P
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Rolling pullups - Ooooer!
The 90 degree bank has more to do with regaining airspeed (as opposed to trying to offload the wings). So the CAA's guideline to apply that bank in the case of any loss of control during manual reversion seems questionable.
Why?
A potential 'rolling pullup' - this is what probably broke Concordski (Tu144) at Paris.
'Do the sums' I suppose is the phrase...
The normal loads on the upcoming wing combined with pitchup loading, 'sum together', so a much greater chance of overstressing and breaking the aircraft.
In short, you ar more likely to overstress the upcoming wing.
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I just found the CAA document on check flights (http://www.caa.co.uk/docs/1455/Check...bruary2009.pdf).
This is the relevant paragraph:
Interestingly, most of that document dates from May 2008. One exception: the part that covers test flights of large aircraft - dating February 2009. I wonder what changed 
Anybody has the pre-February version?
P
This is the relevant paragraph:
Always, RELEASE ANY FORCES that you are holding before re-powering a flight-control system, even if by doing so the aircraft will enter an unusual attitude. It might be possible to put some bank on the aircraft to turn a large pitch-up into a turn manoeuvre before re-powering the system. For a pitch nose-down, it is essential to maintain wings level whilst recovering to the horizon before re- instating power to the controls.
Anybody has the pre-February version?P
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For a pitch nose-down, it is essential to maintain wings level whilst recovering to the horizon before re- instating power to the controls.
... apparently exactly! is not 10 characters so insufficient for a response (too much automation!), so i shall just say, reinforcing my point above about rolling pullups
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I'm surprised at the test being required at FL150, I recall it used to be done at FL350+, but I could be wrong. Why would it be specified to carry out the test at FL150 when you could have another 20,000' for recovery if something went wrong?
With regard to the shakedown flight, the manual reversion being just within limits and then calling for rectification, this is not unfeasible or beyond comprehension.
On the customer acceptance flight test following the maintenance input, if the test was just within tolerances when performed on the shakedown it might have been just outside tolerances on the customer acceptance flight test and you are then required to carry out adjustment of the tab control rods on the ground and fly the aircraft again - more cost. Also, it is usual for the engines to be boroscoped after the flight test and further work carried out if there is an immediate handback planned (re-registration, replacement of a/c data plate, Mode S ident reprogramming, etc.). It is a reasonable decision to get the tab rods inspected and adjusted on the maintenace input to reduce risk of the customer acceptance flight test failing and possibly upsetting any plans in place for the post flight test maintenance and hand-over of the aircraft to the owner.
What is not reasonable is not to write it up in the log so that it can be transferred to the maintenance documentation accurately. It has to be assumed that the manual reversion results were recorded on the "shakedown" flight test documentation and this passed to the engineering organisation but I will be very surprised if this is not, at least, commented upon in the final report.
With regard to the shakedown flight, the manual reversion being just within limits and then calling for rectification, this is not unfeasible or beyond comprehension.
On the customer acceptance flight test following the maintenance input, if the test was just within tolerances when performed on the shakedown it might have been just outside tolerances on the customer acceptance flight test and you are then required to carry out adjustment of the tab control rods on the ground and fly the aircraft again - more cost. Also, it is usual for the engines to be boroscoped after the flight test and further work carried out if there is an immediate handback planned (re-registration, replacement of a/c data plate, Mode S ident reprogramming, etc.). It is a reasonable decision to get the tab rods inspected and adjusted on the maintenace input to reduce risk of the customer acceptance flight test failing and possibly upsetting any plans in place for the post flight test maintenance and hand-over of the aircraft to the owner.
What is not reasonable is not to write it up in the log so that it can be transferred to the maintenance documentation accurately. It has to be assumed that the manual reversion results were recorded on the "shakedown" flight test documentation and this passed to the engineering organisation but I will be very surprised if this is not, at least, commented upon in the final report.
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Having just read this forum and the AAIB report, there are a number of issues to be accounted for and a number of people who questions should be aimed at.
I'm also amazed (or not really) by the number of people who have absolutely NO idea what they're talking about posting views on this site although it is rumour network.
Let’s begin at the beginning.
The crew flew the aircraft to the MRO and carried out a pre-maint shakedown. They were not happy with the manual reversion limits. The CAPTAIN on arriving at the MRO should have been debriefed not only by the accepting engineering staff but also present should have been the Lease agent (Owner) and any questions and irregularities be discussed. Any defects should have been entered into the aircraft Tech Log and then eventually transferred into the aircraft input checkpackage as an incoming defect. This way nothing gets missed and all entries have to be completed and certified prior to the next flight by a suitably qualified engineer. The manual reversion in this case was just within the AMM limits although the owner may have a contractual agreement with the lessor as to the return conditions in this case so adjustment would have to be in agreement with the lessor, owner and MRO for commercial purposes. IT STILL NEEDS TO BE WRITTEN IN THE LOG!!
OK, following the input and the return conditions complied with, (the Lessee may also insist on a wider AMM limitation with agreement from the owner/MRO) as required in the AMM for either the adjustment of both Tab rods, the removal of the elevator tab and replacement of any hinge or the replacement of BOTH rods/eye end bearings a manual reversion test flight is required iaw 27-31-00.
In our company a management flight crew and a licensed engineer type rated and approved is the minimum crew allowed to carry out this flight test. The pilots fly and the engineer sits on the jump seat and controls the hydraulic input in conjunction with the crew. This means the pilots can control anything that may happen and not have to worry about reaching behind and overhead for the hyds. Why was an engineer not present on this flight???? This seems almost certainly a question that needs to be answered and incredibly dangerous for a situation as described here where the Co-Pilot is struggling and communications are not good in a frightening experience.
Make no mistake the crew did exceptionally well here and it could have been all-so-different but in my view an engineer should have been provided by Ezy as effectively they were still the lessor until the completion of a successful test flight thereby transferring to the new end user.
I can't comment on the recovery or the practices used in recovering the aircraft in this situation, I'm not a pilot and wouldn't judge what they did. I have however accepted and delivered many aircraft as an engineer and carried out my last flight test last week following post maintenance and have done numerous manual reversions on both the 73Cl and 73NG so I can only comment on what I have a knowledge of. I have also been a check manager/crew chief responsible for heavy inputs for a number of MRO's and major airlines and have leased/disposed of aircraft as a technical representative for a number of airlines/lease companies.
So my 2 basic questions are, (1) Why wasn't anything recorded by the inbound crew?? (Big Mistake by the Capt) . If its on paper it has to be certified and (2) Why didn't the company/Airline (Ezy in this case)/MRO provide and engineer to act as an additional crew member to allow the flight crew to deal with a potentially difficult situation as this has to be expected when carrying out a manual reversion test??
These flight tests are carried out quite often and are depicted in the AMM is to the reasons why. These reasons are quite specific and controlled and are there to ensure when the loss of Hyd's (Sys A+B) the aircraft is still controllable and the flight test criteria is also quite specific and controlled. They are also definitely NON REVENUE and in specific airspace previously agreed beforehand so it isn't just something anyone can jump in and do (To the uninitiated out there!!). It is part of an engineering procedure in case of a flight eventuality you hope is never going to happen.
Following the failure of the test flight the AMM would have been consulted and the adjustments made as required in accordance with the AMM procedure. The adjustments in this case were incorrect and made in the wrong direction which is an easy mistake to make but should have been picked up on the duplicate inspection. (At this point the company QA dept should be involved with this incident and ask the questions why the procedure of correction went so wrong). I sympathise with the engineers involved and can see how the mistake was made. BA at GLA a few years ago turned a 73Cl into an orbital spaceshuttle by making just this mistake so as you can see it can happen anywhere, has done before and will do again.
Normally once the adjustments have taken place no further flight test is required although this is at the discretion the companies concerned.
I hope this may go some way to answering some of the more outward posts placed here.
I'm also amazed (or not really) by the number of people who have absolutely NO idea what they're talking about posting views on this site although it is rumour network.
Let’s begin at the beginning.
The crew flew the aircraft to the MRO and carried out a pre-maint shakedown. They were not happy with the manual reversion limits. The CAPTAIN on arriving at the MRO should have been debriefed not only by the accepting engineering staff but also present should have been the Lease agent (Owner) and any questions and irregularities be discussed. Any defects should have been entered into the aircraft Tech Log and then eventually transferred into the aircraft input checkpackage as an incoming defect. This way nothing gets missed and all entries have to be completed and certified prior to the next flight by a suitably qualified engineer. The manual reversion in this case was just within the AMM limits although the owner may have a contractual agreement with the lessor as to the return conditions in this case so adjustment would have to be in agreement with the lessor, owner and MRO for commercial purposes. IT STILL NEEDS TO BE WRITTEN IN THE LOG!!
OK, following the input and the return conditions complied with, (the Lessee may also insist on a wider AMM limitation with agreement from the owner/MRO) as required in the AMM for either the adjustment of both Tab rods, the removal of the elevator tab and replacement of any hinge or the replacement of BOTH rods/eye end bearings a manual reversion test flight is required iaw 27-31-00.
In our company a management flight crew and a licensed engineer type rated and approved is the minimum crew allowed to carry out this flight test. The pilots fly and the engineer sits on the jump seat and controls the hydraulic input in conjunction with the crew. This means the pilots can control anything that may happen and not have to worry about reaching behind and overhead for the hyds. Why was an engineer not present on this flight???? This seems almost certainly a question that needs to be answered and incredibly dangerous for a situation as described here where the Co-Pilot is struggling and communications are not good in a frightening experience.
Make no mistake the crew did exceptionally well here and it could have been all-so-different but in my view an engineer should have been provided by Ezy as effectively they were still the lessor until the completion of a successful test flight thereby transferring to the new end user.
I can't comment on the recovery or the practices used in recovering the aircraft in this situation, I'm not a pilot and wouldn't judge what they did. I have however accepted and delivered many aircraft as an engineer and carried out my last flight test last week following post maintenance and have done numerous manual reversions on both the 73Cl and 73NG so I can only comment on what I have a knowledge of. I have also been a check manager/crew chief responsible for heavy inputs for a number of MRO's and major airlines and have leased/disposed of aircraft as a technical representative for a number of airlines/lease companies.
So my 2 basic questions are, (1) Why wasn't anything recorded by the inbound crew?? (Big Mistake by the Capt) . If its on paper it has to be certified and (2) Why didn't the company/Airline (Ezy in this case)/MRO provide and engineer to act as an additional crew member to allow the flight crew to deal with a potentially difficult situation as this has to be expected when carrying out a manual reversion test??
These flight tests are carried out quite often and are depicted in the AMM is to the reasons why. These reasons are quite specific and controlled and are there to ensure when the loss of Hyd's (Sys A+B) the aircraft is still controllable and the flight test criteria is also quite specific and controlled. They are also definitely NON REVENUE and in specific airspace previously agreed beforehand so it isn't just something anyone can jump in and do (To the uninitiated out there!!). It is part of an engineering procedure in case of a flight eventuality you hope is never going to happen.
Following the failure of the test flight the AMM would have been consulted and the adjustments made as required in accordance with the AMM procedure. The adjustments in this case were incorrect and made in the wrong direction which is an easy mistake to make but should have been picked up on the duplicate inspection. (At this point the company QA dept should be involved with this incident and ask the questions why the procedure of correction went so wrong). I sympathise with the engineers involved and can see how the mistake was made. BA at GLA a few years ago turned a 73Cl into an orbital spaceshuttle by making just this mistake so as you can see it can happen anywhere, has done before and will do again.
Normally once the adjustments have taken place no further flight test is required although this is at the discretion the companies concerned.
I hope this may go some way to answering some of the more outward posts placed here.
Cool as a moosp
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Jofm5 thank you for the link to the AAI link, much appreciated, so we can see who knew what they were talking about over the last couple of months and who was way into spacey stuff. A re-read of the thread will educate us all as to who are the smart cookies here.
An interesting report, with very minor recommendations. That usually means that those involved were doing the right thing, and through their superior airmanship managed to save the day.
This was a test flight, and it was resolved to a safe landing. Although the AAI cannot write it, by their conclusions and limited recommendations they are saying well done. And that is the highest accolade you will ever get from the AAI.
And to those who thought terror and plunge were acceptable descriptions of what occurred you do not understand flight tests and the character of those who do them. You do however understand journalism.
Minor whinge here. When are you guys at the AAI going to get digital and produce your reports in a single column? Double column reports are difficult to read on screen and went out with MADMEN.
An interesting report, with very minor recommendations. That usually means that those involved were doing the right thing, and through their superior airmanship managed to save the day.
This was a test flight, and it was resolved to a safe landing. Although the AAI cannot write it, by their conclusions and limited recommendations they are saying well done. And that is the highest accolade you will ever get from the AAI.
And to those who thought terror and plunge were acceptable descriptions of what occurred you do not understand flight tests and the character of those who do them. You do however understand journalism.
Minor whinge here. When are you guys at the AAI going to get digital and produce your reports in a single column? Double column reports are difficult to read on screen and went out with MADMEN.
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scousegit,
I am somewhat surprised by your assertion that "Normally once the adjustments have taken place no further test flight is required" . . in this case what is the safeguard against someone turning the thingy (tech description on my part
) the wrong way, or too far ?
I thought I read that it is a very delicate process to get the position "just so ", are you saying that after it is adjusted it doesn't have to be reflown again & the first one to find out any misadjustment is some poor sod a few months down the line who has a HYD failure, or. . . (not entirely impossibly
) am I missing /misinterpreting something you said ?
I am somewhat surprised by your assertion that "Normally once the adjustments have taken place no further test flight is required" . . in this case what is the safeguard against someone turning the thingy (tech description on my part
) the wrong way, or too far ? I thought I read that it is a very delicate process to get the position "just so ", are you saying that after it is adjusted it doesn't have to be reflown again & the first one to find out any misadjustment is some poor sod a few months down the line who has a HYD failure, or. . . (not entirely impossibly
) am I missing /misinterpreting something you said ?
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7320
Yes but with typical editorial mishandling, the lead article in the EDP had a pic of an Easy A320. When questioned this morning, the news desk lackie said, "thought I should have confirmed the aircraft type before we went to print"!
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Anything can help bring an aircraft down (more so these days it seems due to automation/complexity/interconnectedness) but control surface/trim/servo tabs are so critical that if there is any doubt in the mechanics or inspector's mind of degree or sense(direction) of adjustment, surely eat humble pie and get Boeing to fax more explicit instructions. Check and double check with your peers and supervisors.
I also find it somewhat surprising that there isn't a call in this procedure for a way to check pre-existing power-trim forces (excessive) before pulling the hydrualics, to avoid going from the frying pan into fire. e.g. a quick and dirty check on how hard the powered systems are working
I also find it somewhat surprising that there isn't a call in this procedure for a way to check pre-existing power-trim forces (excessive) before pulling the hydrualics, to avoid going from the frying pan into fire. e.g. a quick and dirty check on how hard the powered systems are working
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CPS,
Sorry my mistake the AMM has now been revised and the statement is now as follows -
Sorry my mistake the AMM has now been revised and the statement is now as follows -
Make sure that you satisfy the flight test requirement before a revenue service of the airplane.
However, if it is not possible to perform a flight test before revenue service, you can operate the airplane in revenue service for a maximum of 10 days before you successfully complete the flight test.
A second flight test is necessary if the pitch up or pitch down trim is more than the limit during the first flight test.
A second flight test is necessary if the pitch up or pitch down trim is more than the limit during the first flight test.
However to obtain a CRS following an engineering input you would need to carry out at least 1 flight test. the adjustments can then be made and the next flight test can be defered for a maximum of 10 days.
My apologies.