View Full Version : B767 Breakout Mechanism - the Airtours serious incident
crossingclimb
3rd May 2009, 06:56
A friend who's converting on to the B767 at the moment is having trouble understanding the flying control breakout mechanism.
I tried to explain it to him (I have 4000 hours on type) and couldn't. After much searching, I found a Jan 2004 thread on the Egyptair 990 crash which contained the following input:
"...I remember the Airtours 767 departing from the Canaries which (after a Monarch mechanic had left a very large torch in a wing inspection compartment) found itself unable to turn left. After a wings vertical moment or two when both pilots tried the breakout procedure (didn't work. no-one explained why), they continued back to Manchester (no left turns on the way).
Airtours sat heavily on the incident, which they (after the press got wind of it) described as a minor malfunction ably handled by the crew.
I could never find any signs of an investigation, or an incident report, or any attempts by a seemingly inert CAA to pass on useful information to other users.
In the end the captain went to a national broadsheet and it was given half a page of shock/horror..and then....nothing happened as far as I know.
In a responsible airline everyone would have learned a lot from the whole thing. In the air force, the incident report would have been an inch thick and still be being read in crewrooms."
Did anyone ever investigate the incident?
Why didn't breakout work?
Why was a UK airline allowed to cover up a major occurrence?
Can anyone who was in Airtours at the time, or in a responsible part of the CAA, throw any light on how it could be hushed up?
And the original query: how should breakout work???
Quite simply: it never happened.
If the aircraft was unable to turn to the left how was it able to return to wings level once they had started a right turn?
Edit:
I've just found this:
The controls jumped out of his hand at 4,000 feet. It was every pilot's nightmare - News - The Independent (http://www.independent.co.uk/news/the-controls-jumped-out-of-his-hand-at-4000-feet-it-was-every-pilots-nightmare-1354254.html)
Jetjock330
3rd May 2009, 10:06
SUBJECT
Simulator training for technical crew to equip them to handle jammed ailerons in flight on Boeing aircraft.
OCCURRENCE SUMMARY
Shortly after departing from runway 34L at Sydney, the pilot of a Boeing 747 advised the departures controller that he could only comply with left turns, and that he needed to jettison fuel and return to the airfield. A distress phase was declared and the aircraft was vectored left to an area over water where fuel was dumped. The aircraft was subsequently vectored to the centreline of runway 34L and landed safely.
The subsequent investigation found that a plastic aileron cable guard had broken and jammed the aileron cables where they run vertically up the left sidewall of the aircraft. The pilot reported that he was unable to input any right aileron control and it appeared to be jammed.
ANALYSIS
The roll control surfaces on Boeing aircraft consist of hydraulically-powered inboard and outboard ailerons (and spoilers) which are normally controlled by rotating either control wheel. The aileron cable control systems are constructed in two separate sets, linked at the control wheels.
The control wheels are connected through an override mechanism which allows either wheel to move independently if the aileron control system connected to the other wheel jams and a significant manual force is applied to the free wheel. Roll control is then available through the ailerons on the wing corresponding to the free wheel.
The pilot in command of the above mentioned aircraft advised that after the aircraft had been landed, he was present when repairs were carried out and was surprised at the aileron breakout force required to override a jammed system. Ground training he had received covered aileron breakout (override) procedures but he believed it would be beneficial to have it physically demonstrated during simulator training in case of such an emergency.
Discussions with other technical crews revealed that, while they were aware of the system, they were generally not aware of the physical forces required to break out the aileron control system in the event of an aileron system jam.
The Boeing Company does not recommend activating the breakout feature of the aileron control system on a regular basis due to possible stretching of aileron cables and excessive wear to a system that is installed for emergency use only.
It has been reported that flight simulators in use by operators of Boeing aircraft in Australia can be programmed to enable demonstration of aileron control breakout forces. If the simulators are programmed correctly, all technical crews can be safely exposed to this aspect during simulator training.
The Boeing Commercial Airplane Company advised that Boeing B737, B747, B757 and B767 aircraft are all fitted with similar emergency aileron override and breakout systems (http://www.atsb.gov.au/publications/recommendations/1997/R19970128.aspx).
SAFETY DEFICIENCY
The aircraft is designed to be flown from either control position should one side become jammed. The pilot was aware of this design feature but was not aware of the amount of force required to activate the breakout system.
Technical crews are instructed on this control feature during ground training but are not physically exposed to the forces required, either on an aircraft or in a simulator.
crossingclimb
3rd May 2009, 13:00
Thanks for the link to the article in the Independent.
Here it is:
“The controls jumped, out of his hand at 4,000 feet. It was every pilots nightmare”by Christian Wolmar (Independent newspaper, 26/11/96).
It was the moment every pilot dreads. The controls on Flight AIH 838 - a Boeing 757 carrying 241 passengers and crew - became jammed soon after take-off from Fuerteventura in stormy conditions, bound for East Midlands and Newcastle. Unknown to the flight crew, Captain Ray Cockerton and first officer Andrew Redknapp, a torch had been left in the right-hand wing. During take-off which, unusually, was at full power because of the poor conditions, the torch lodged in the aileron, the flap which is used to turn the plane. It had been left there by an engineer at Luton the day before and had not caused any problem in three previous flights.
Mr Redknapp was flying the aircraft on auto-pilot at around 4,000 feet, soon after take-off, when he tried to turn left. The controls jumped out of the auto-pilot mode. After a second failed attempt, Captain Cockerton took over the controls with the auto-pilot disengaged.
“Having controls which don't respond is the classic pilot's nightmare” he said. He used the rudder, which is not normally operated during flights, to reach the right heading, get away from the mountains and over the sea.
The two flight crew then tried to find out what was wrong. Mr Redknapp went into the cabin but could see nothing amiss on the wings. They went through the checklist and contacted the Monarch engineers who had serviced the plane at Luton. The emergency checklist procedure requires both pilots to push as hard as possible to free the controls. When they did, the plane went into a violent lurch, banking at 60 degrees. Captain Cockerton considered his options but bearing in mind the bad weather in the Canaries, which made any landing impossible, decided to press on to the UK. “At this stage, 1 thought we had a 50 per cent chance of getting down safely," Captain Cockerton said. He began to consider which airport in Britain to land at and declared a full emergency. He chose Manchester because the direction of the runway and the wind was most appropriate to his situation and wind direction and he knew that the airport had good emergency services.Over the Welsh hills, he and his first officer both once more tried to dislodge the blockage but the plane again lurched violently. The two thought that the problem lay with a jammed aileron at the end of the right wing but had no idea what had caused it. While the six cabin crew had been informed, they did not tell passengers - to avoid causing panic. Captain Cockerton managed to bring the plane in at a small angle to the runway to allow for the wind but the aileron was still jammed at touchdown. However, the report produced by the company for the Civil Aviation Authority suggests that emergency action had solved the problem, resulting in a normal manual landing: I don't think the report conveys, the gravity of the situation," he said. After landing, according to the CAAs report, "the crew demonstrated the problem, at which point a large metal torch was forced through the wing below the right hand aileron". The passengers were never told about what had caused the incident, but 30 refused to take the plane provided by Airtours to take them back to East Midlands and travelled by land.At his home in the east Midlands, Captain Cockerton wrote a four-page report and was told by the company that there would be a debriefing session with all the crew. This never materialised.Apart from a thank you letter from Airtours managers, the incident was barely mentioned again and within a week he was back on duty. Captain Cockerton said that was a mistake: "I felt occasionally tearful but otherwise I was apparently fine for three or four months, then I started getting flashbacks, insomnia and irritability." Eventually, in June, he felt that his mental state warranted reporting sick and he sought medical advice He was diagnosed as suffering from post-traumatic stress syndrome and referred to a specialist for successful counselling sessions. Captain Cockerton resigned a few days later and now flies for another leading airline. As for the engineer who left the torch, he put up a big notice in his mess at Luton asking if anyone had seen his torch. Last night, Monarch refused to comment on whether he was disciplined. (on another page)
Airtours, Britain's second largest tour operator, misled air-safety authorities over an emergency on an aircraft carrying almost 250 holidaymakers, when the pilot could not turn properly to the left during a four-hour flight.
Airtours, has admitted to The Independent that an incident report sent to the Civil Aviation Authority was inaccurate because it implied the pilot had regained control over the aircraft, which had a maintenance worker's torch jammed in critical controls inside the wing. The plane, on a holiday flight from the Canaries to East Midlands airport last year, was diverted and made an emergency landing at Manchester. When the crew several times tried to correct the problem by pushing hard against the controls, to unjam the mechanism, the plane lurched in a 60-degree bank. Yet the mandatory occurrence report (MOR) which Airtours filed says the pilots managed to break through the jammed equipment so that it did not restrict handling of the aircraft. If an accurate report had been made, the Air Accident Investigation Branch would probably have made a full investigation and publicised its findings.
The near-disaster received no publicity and other airlines were not warned that one of the procedures employed by the crew, in accordance with Boeing's flight-operations manual, put the aircraft at risk of crashing.
Last night a spokesman for the Civil Aviation Authority said it would be contacting Airtours over the inaccuracy. The company did not publicise the incident in its internal newsletter, which is standard practice among airlines. When the Boeing 757 flight AIH 838, bound from Fuerteventura to East Midlands and Newcastle on 13 December, landed at Manchester, it was discovered that a torch left by a engineer employed by Monarch was blocking controls to the right aileron. The aileron, a wing flap, could not move downwards, which prevented the plane making a left-hand turn.
In the MOR filed by the company to the CAA, it says the plane landed "with QRH [quick-reference handbook] action achieving aileron break-out", implying that efforts of the crew disconnected the faulty aileron, allowing them to steer using other flaps.
In fact, this never occurred and the captain had great difficulty in bringing the aircraft down in windy conditions. Colin Penny, Airtours Director of Flight Operations admits the MOR was wrong and initially said this was a result of information given by the captain, Ray Cockerton. However, after The Independent told the company it had seen Captain Cockerton's report, Captain Penny said the report was based on information supplied by the engineering department. The Independent first contacted Airtours over the incident, its press officer, Sean Robinson, said there was no emergency on the ground, only in the air, and that the aircraft could have landed at any UK airport but went to Manchester "because it is our maintenance base".
In fact, the pilot announced a full emergency and was unable to land elsewhere because of wind conditions and runway position.
It appears Airtours lied to the CAA, and that breakout did not occur.
Anyone know why it didn't?
Flap40
3rd May 2009, 13:46
I remember an Excalibur A320 getting airborne from Gatwick and having roll problems and I also remember a separate report (but cannot find it) of a torch being spotted by a passenger under a spoiler during the landing roll on a filght but that had not affected the flight.
I do not remember something similar on the 767.
Excalibur report is at Air Accidents Investigation: 2/1995 G-KMAM (http://www.aaib.gov.uk/publications/formal_reports/2_1995_g_kmam.cfm)
Hmmm, breakout procedures.
These were on the B707 as well.
However, there is one well designed first generation wide-body jet transport airplane that does not need this breakout procedure, it uses something else, a 'Pull Roll Disconnect' handle, on the right hand side of the throttle pedestal, to accomplish much of the same procedure.
Roll problems encountered?
Pull Roll Disconnect handle, end of drama.
Simple as that.
Of course, it's on the L1011....no surprise there.:ok:
Flap40
3rd May 2009, 17:49
Others with roll (and pitch) disconnect handles are the 146 and the Embraer 170/190 series.
Others with roll (and pitch) disconnect handles are the 146 and the Embraer 170/190 series.
Good show, thinking ahead by design engineers to make the pilots job easier and...safer.
Same on the EMB120 and Saab340.
Bigbuster
22nd Jul 2009, 19:14
Hello There,
I was the pilot on the B757 which had the torch stuck in the wing. If you want to discuss anytime we can. I had a few difficult nights after this one. A very strange feeling when you want to turn left at 1,000 ft and you can't and you are heading for a thunderstorm. Not knowing what was causing the problem was very difficult. Would you believe this is the first time I have ever signed into this service and I see an article about me.
Look forward to discussing some time.
Regards
AR
Chilli Corneto
23rd Jul 2009, 04:24
Interesting story here.
I'd be interested to know what trouble shooting you did on the day? I'm not rated on the 757/767 but are there circuit breakers for the inboard & outboard Ailerons? If there are, would it have been possible to pop either (not at the same time) the outboards or inboards CB's and thereby identifying and in turn isolating the troublesome Aileron? I would guess roll authority would not be as great if you had to isolate the outboard ailerons and only land with the remaining inboards controlling roll but that might of given you some reassurance and confidence in handling the aircraft for the remaining journey. Or allow you to divert urgently should you have needed too.
I'm sure all of this is in the QRH but i'd love to know how it was handled. I'm still learning so apologies if there's no logic with my reasoning or state the obvious.
Cheers,
Chilli.
Some misconceptions on the subject.
"The aircraft could only make right (or left) turns" - if it can turn one way, and can then terminate that turn, then it can also turn the other way.
The breakout feature is not a case of "break something loose and solve the problem for the rest of the flight". If one side of the (pitch or roll) system is jammed, the not jammed part of the system can still be moved, but everytime that the movement is made, the "connecting force" of the breakout mechanism has to be overcome. In that respect, the use of a connecting pin that can be removed sounds like a more comfortable system. (Wow, that must sound like music to 411A).
The breakout system can be seen conceptually as the clutch of a car: the clutch connects two parts of a driveshaft, so that they rotate as one shaft. The connection is not bolted together, but pressed together by strong springs. Of course, there are differences: in case of a clutch, you break the connection with a dedicated pedal, whereas in the case of the flight controls, well, you need to block an aileron with a large metal torch for instance and then you need to overpower the springs everytime that you want to move the control wheel.
As for the question of circuit breakers: those items are used in electrical circuits.
No it is not possible to disconnect a flight control from the system as if it is one of the radio sets on the flight deck. The controls are a set of panels that work as a team. The disconnection is through systems as the breakout feature (Boeing) or the disconnect mechanisms mentioned by 411A (Lockheed).
As far as training and knowledge is concerned: even though I had read in the manuals about the jammed control features (of the 767), it wasn't untill I read the report on the Egyptair case that I realized that it is possible to actuate the elevators (and ailerons) in opposite sense. Ever since, I am aching to try it during the flight control check on the ground, but discipline keeps me from using the system inappropriately.
Ever since, I am aching to try it during the flight control check on the ground, but discipline keeps me from using the system inappropriately.
A wise decision, I would think.
Along these lines, I am reminded of the telephone call I received during my hotac rest, wherein the rostered FD crew, newly converted to the L1011, were trying control checks with the hydraulics switched off...and in doing so, received aileron cross-hatch enunciation...and then didn't then know what to actually do about it.
After this, the fleet manager distributed a memo to all FD crew...in essence, RTFB thank you very much.:rolleyes:
Bullethead
23rd Jul 2009, 12:25
G'day Gents,
In the airline I fly for part of the B767 endorsement sim training included a control freeze and the use of the breakout facility to fly the aeroplane. The breakout force is quite high and initially I though the whole thing had frozen, but once you get a feel for it flying the aeroplane was straightforward though jerky everytime you needed to overcome the breakout.
Regards,
BH.
Totally ignorant of the discussion at hand, but if you would pardon the intrusion for a second:
If the aircraft was unable to turn to the left how was it able to return to wings level once they had started a right turn?
Rudder? (second effect of)
Capt Pit Bull
23rd Jul 2009, 13:36
Others with roll (and pitch) disconnect handles are the 146
The 146/RJ has breakout AND disconnect handles.
Note the capitalisation!
In roll, you need to use BOTH features to be sure you've fully disconnected the two halves of the circuit.
There's a break out between the columns, achieved by both crew members making control inputs in opposite directions.
The 'handle' disconnects the interconnection between the ailerons.
In pitch the columns can be disconnected by breakout OR by using the handle. If you only break them out by force, they will re-engage when brought back to the same position though.
pb
On post #13: A nice anecdote 411A!
On post #13: A nice anecdote 411A!
Thanks EMIT...and what's more, my story is facual.
Getting down to brass tacks, it does indeed pay to actually RTFB...the respective fleet manager was quite correct with his memo.
kenparry
24th Jul 2009, 06:36
I'm not rated on the 757/767 but are there circuit breakers for the inboard & outboard Ailerons?
The roll control system on the B757 does not include inboard ailerons, whereas that on the B767 does. As stated above, no circuit breakers!
Bigbuster
7th Jul 2012, 08:56
I know you mean you mean no harm with your
comments, but please be advised that it did happen
and I was unfortunate enough to be one of the pilots
flying it. We actually lost control temporarily over
the Bay of Biscay. We were desperately trying to find
somewhere to land that was into wind.
It was winter and the UK was the best option although
the wind direction was not ideal. This of course
meant we were able to burn as much fuel off
as we needed to to minimise the risk of a strong fire.
We elected to land at Manachester. We were asked
by ATC what our chances were of a successful
landing. We put it at 50/50. Manchester put their
disaster policy into effect. It was only recently
that I met the policewoman that took the call at one of
Manchester's Police stations. We were very luck to make
it onto the runway. My captain had a breakdown and left.
All the cabin crew resigned and only I was left.
I don't normally mind what people normally write, but please just
don't dismiss it as " it never happened" I have a letter of commendation
to prove that it did. Thanks guys, happy flying.