Another 737 rudder incident
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I now fly the A320 and that is also perfect........
Don't forget that the Direction Generale de l'Aviation Civile can sue you for libel if you suggest otherwise. And win.
Back to the 737. From the first AP article:
"After the plane touched down, the pilots said the rudder swung left and then fully to the right, causing a loud bang
Boeing spokeswoman Liz Verdier said a number of factors could have been responsible, including ... the weather."
Say what you want about Boeing but don't say that its spokeswoman is humourless.
According to a Reuters report of this incident, "Boeing spokeswoman Liz Verdier said the company has designed a new rudder system to comply with the [FAA] directive and is ready to retrofit all of the nearly 2,000 Boeing 737s in the American fleet."
According to AP, "Boeing announced in September that it would ... begin installing new rudder systems on 737s in 2003."
The second statement casts doubt on the readiness expressed in the first: if Boeing is "ready" for the retrofit, then why wait until 2003? I seem to recall reading that the new design has not been tested for unanticipated adverse consequences. Anyone know the status?
A detailed preliminary incident report of UAL 578 can be found here:
<a href="http://www.ntsb.gov/ntsb/brief.asp?ev_id=20011219X02423&key=1" target="_blank">http://www.ntsb.gov/ntsb/brief.asp?ev_id=20011219X02423&key=1</a>
Don't forget that the Direction Generale de l'Aviation Civile can sue you for libel if you suggest otherwise. And win.
Back to the 737. From the first AP article:
"After the plane touched down, the pilots said the rudder swung left and then fully to the right, causing a loud bang
Boeing spokeswoman Liz Verdier said a number of factors could have been responsible, including ... the weather."
Say what you want about Boeing but don't say that its spokeswoman is humourless.
According to a Reuters report of this incident, "Boeing spokeswoman Liz Verdier said the company has designed a new rudder system to comply with the [FAA] directive and is ready to retrofit all of the nearly 2,000 Boeing 737s in the American fleet."
According to AP, "Boeing announced in September that it would ... begin installing new rudder systems on 737s in 2003."
The second statement casts doubt on the readiness expressed in the first: if Boeing is "ready" for the retrofit, then why wait until 2003? I seem to recall reading that the new design has not been tested for unanticipated adverse consequences. Anyone know the status?
A detailed preliminary incident report of UAL 578 can be found here:
<a href="http://www.ntsb.gov/ntsb/brief.asp?ev_id=20011219X02423&key=1" target="_blank">http://www.ntsb.gov/ntsb/brief.asp?ev_id=20011219X02423&key=1</a>
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This UAL 737 rudder incident below is so similar to the Bournemouth 737 event
So toilet-brush or not, my money goes on it being a wee-run of this one:
at <a href="http://www.aaib.detr.gov.uk/formal/gbgji/gbgji.htm" target="_blank">http://www.aaib.detr.gov.uk/formal/gbgji/gbgji.htm</a>
Pee-pee in the E&E
Those electrolytes in the crystalline deposits can give you more swings than Benny Goodman (or the baton in front of the Boston Philharmonic).
So toilet-brush or not, my money goes on it being a wee-run of this one:
at <a href="http://www.aaib.detr.gov.uk/formal/gbgji/gbgji.htm" target="_blank">http://www.aaib.detr.gov.uk/formal/gbgji/gbgji.htm</a>
Pee-pee in the E&E
Those electrolytes in the crystalline deposits can give you more swings than Benny Goodman (or the baton in front of the Boston Philharmonic).
I thought B737 pilots may find this (taken from the NTSB site) of interest:
NTSB Identification: CHI02IA050
Scheduled 14 CFRPart 121 operation of Air Carrier United Airlines (D.B.A. United Airlines)
Incident occurred Thursday, December 13, 2001 at Chicago, IL
Aircraft:Boeing 737-322, registration: N359UA
Injuries: 99 Uninjured.
This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.
On December 13, 2001, at 1203 central standard time, a Boeing 737-322, N359UA, operated by United Airlines as flight 578, declared an emergency due to a reported "rudder malfunction" during decent to the Chicago O'Hare International Airport (ORD), Chicago, Illinois. Visual meteorological conditions prevailed at the time of the incident. The 14 CFR Part 121 passenger flight was operating on an instrument rules flight plan. The 2 pilots, 4 flight attendants and 93 passengers reported no injuries. The flight departed from the Lambert-St. Louis International Airport, St. Louis, Missouri, at 1129, en route to ORD.
The first officer reported in a written statement, "... At approximately 9,300', during the descent the aircraft began to bounce and slowly bank to the left, which led me to believe we were experiencing wake turbulence. With the A autopilot still engaged the airplane began a correction back to the right while continuing with the bouncing sensation. The airplane rapidly achieved approximately 10 degrees of bank when the captain announced that he was disengaging both the autopilot and the autothrottles. The rate of bank accelerated in a fashion similar to when one turns the airplane with the speed brakes deployed to the flight detent. As a result of the yawing and bouncing sensation I instructed the flight attendants to 'be seated immediately' via the PA. The airplane was now in an approximate 45 degree bank to the right."
"The captain was very obviously opposing the roll with both left rudder pressure and left aileron. The captain stated something to the effect 'I think it's a rudder problem'. I then looked at the A and B system hydraulic quantity and pressure gauges and saw normal indications. I then began assisting the captain on the controls with both the left aileron and left rudder pressure. At this point I noticed the airspeed was diminishing from 250 KIAS to about 238 KIAS. I then pushed forward on the control column to increase the airspeed in hopes of increasing control effectiveness. As our airspeed increased the effect of left control inputs began to move the airplane to a more controllable attitude. The captain appeared to regain control of the airplane at approximately 8,200'."
"At this point the captain still had both hands on the control wheel with significant left aileron input. As a result I initiated an increase in power to maintain 250 KIAS and 8000'. The captain then asked me to declare an emergency. I stated that we were declaring an emergency due to a rudder malfunction. I stated we had 100 souls on board and approximately 10,300 pounds of fuel and I would get back to ATC as time permitted. I then initiated the QRC for the 'uncommanded rudder' checklist. The reference actions in the checklist did not provide any relief to the amount of left aileron and left rudder pressure required to maintain control of the aircraft."
"Upon completion of each item on the checklist I tried to verify the hydraulic pressure and quantity indications to see if there was a change. I did not see any change on either. The captain requested that I let ATC know that we needed 27L. I did so. I asked the captain if I should tell the purser to prepare the cabin for evacuation. The captain agreed. I then called the purser and stated 'we have declared an emergency due to a rudder problem, prep the cabin for evac, you have approximately five minutes'. The purser acknowledged my instructions."
"Approach then cleared us to 4000' and vectored us to downwind. We were then cleared to 2500' and 210 knots. At 220 KIAS the captain called for flaps 2, I did so. The captain then stated 'looks like a slam dunk'. He then utilized speed brakes and called for flaps 5. ATC then turned us on a base leg and cleared us to 2100' and 180 knots. The captain then stowed the speed brakes. At approximately 195 KIAS the captain called for flaps 10 and 'gear down final descent checklist'. At this time we were given a final vector and cleared for the ILS 27L. I armed the approach mode after identifying the ILS frequency. It became obvious that the captain's flight director was not giving accurate localizer guidance when the captain discovered his course was still set to 220. He then selected 270 and joined the localizer and glideslope for 27L. I contacted the tower just inside the marker and stated again that we were an emergency aircraft and would like the trucks. Tower acknowledged and cleared us to land."
"We flew a flaps 30 approach and landing to 27L The captain was stabilized per UAL criteria well before 1000' AGL. Between 1000' and 500' AGL the captain commented on how it was becoming increasingly difficult to control the airplane with left rudder pressure and left aileron. At 500' I joined the captain on the controls per his request."
"The airplane landed on the centerline in the touchdown zone on 27L. The speed brakes automatically deployed upon wheel spin up. The captain utilized some engine reversing and the autobrakes began to decelerate the aircraft also. Together the captain and I attempted to maintain directional control of the aircraft throughout the landing rollout with the use of rudder input. It became increasingly difficult to do this as the airplane slowed. About when I called '100 knots' I heard a loud ping or thud when the rudder simultaneously locked out all control input causing the left pedal to push against my foot."
"The airplane was brought to a stop just short of the Tango highspeed taxiway..."
NTSB Identification: CHI02IA050
Scheduled 14 CFRPart 121 operation of Air Carrier United Airlines (D.B.A. United Airlines)
Incident occurred Thursday, December 13, 2001 at Chicago, IL
Aircraft:Boeing 737-322, registration: N359UA
Injuries: 99 Uninjured.
This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.
On December 13, 2001, at 1203 central standard time, a Boeing 737-322, N359UA, operated by United Airlines as flight 578, declared an emergency due to a reported "rudder malfunction" during decent to the Chicago O'Hare International Airport (ORD), Chicago, Illinois. Visual meteorological conditions prevailed at the time of the incident. The 14 CFR Part 121 passenger flight was operating on an instrument rules flight plan. The 2 pilots, 4 flight attendants and 93 passengers reported no injuries. The flight departed from the Lambert-St. Louis International Airport, St. Louis, Missouri, at 1129, en route to ORD.
The first officer reported in a written statement, "... At approximately 9,300', during the descent the aircraft began to bounce and slowly bank to the left, which led me to believe we were experiencing wake turbulence. With the A autopilot still engaged the airplane began a correction back to the right while continuing with the bouncing sensation. The airplane rapidly achieved approximately 10 degrees of bank when the captain announced that he was disengaging both the autopilot and the autothrottles. The rate of bank accelerated in a fashion similar to when one turns the airplane with the speed brakes deployed to the flight detent. As a result of the yawing and bouncing sensation I instructed the flight attendants to 'be seated immediately' via the PA. The airplane was now in an approximate 45 degree bank to the right."
"The captain was very obviously opposing the roll with both left rudder pressure and left aileron. The captain stated something to the effect 'I think it's a rudder problem'. I then looked at the A and B system hydraulic quantity and pressure gauges and saw normal indications. I then began assisting the captain on the controls with both the left aileron and left rudder pressure. At this point I noticed the airspeed was diminishing from 250 KIAS to about 238 KIAS. I then pushed forward on the control column to increase the airspeed in hopes of increasing control effectiveness. As our airspeed increased the effect of left control inputs began to move the airplane to a more controllable attitude. The captain appeared to regain control of the airplane at approximately 8,200'."
"At this point the captain still had both hands on the control wheel with significant left aileron input. As a result I initiated an increase in power to maintain 250 KIAS and 8000'. The captain then asked me to declare an emergency. I stated that we were declaring an emergency due to a rudder malfunction. I stated we had 100 souls on board and approximately 10,300 pounds of fuel and I would get back to ATC as time permitted. I then initiated the QRC for the 'uncommanded rudder' checklist. The reference actions in the checklist did not provide any relief to the amount of left aileron and left rudder pressure required to maintain control of the aircraft."
"Upon completion of each item on the checklist I tried to verify the hydraulic pressure and quantity indications to see if there was a change. I did not see any change on either. The captain requested that I let ATC know that we needed 27L. I did so. I asked the captain if I should tell the purser to prepare the cabin for evacuation. The captain agreed. I then called the purser and stated 'we have declared an emergency due to a rudder problem, prep the cabin for evac, you have approximately five minutes'. The purser acknowledged my instructions."
"Approach then cleared us to 4000' and vectored us to downwind. We were then cleared to 2500' and 210 knots. At 220 KIAS the captain called for flaps 2, I did so. The captain then stated 'looks like a slam dunk'. He then utilized speed brakes and called for flaps 5. ATC then turned us on a base leg and cleared us to 2100' and 180 knots. The captain then stowed the speed brakes. At approximately 195 KIAS the captain called for flaps 10 and 'gear down final descent checklist'. At this time we were given a final vector and cleared for the ILS 27L. I armed the approach mode after identifying the ILS frequency. It became obvious that the captain's flight director was not giving accurate localizer guidance when the captain discovered his course was still set to 220. He then selected 270 and joined the localizer and glideslope for 27L. I contacted the tower just inside the marker and stated again that we were an emergency aircraft and would like the trucks. Tower acknowledged and cleared us to land."
"We flew a flaps 30 approach and landing to 27L The captain was stabilized per UAL criteria well before 1000' AGL. Between 1000' and 500' AGL the captain commented on how it was becoming increasingly difficult to control the airplane with left rudder pressure and left aileron. At 500' I joined the captain on the controls per his request."
"The airplane landed on the centerline in the touchdown zone on 27L. The speed brakes automatically deployed upon wheel spin up. The captain utilized some engine reversing and the autobrakes began to decelerate the aircraft also. Together the captain and I attempted to maintain directional control of the aircraft throughout the landing rollout with the use of rudder input. It became increasingly difficult to do this as the airplane slowed. About when I called '100 knots' I heard a loud ping or thud when the rudder simultaneously locked out all control input causing the left pedal to push against my foot."
"The airplane was brought to a stop just short of the Tango highspeed taxiway..."
ex-Tanker
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What can make an aircraft swing?
The rudder itself, Thrust assymetry (short pop or otherwise) Dragging Brake, Yaw Damper input, Atmospheric condition (wake or general) Other flight control assymetry.
As did 'L337', so did I experience a sharp swing on T/O about a year and a half back. It happened in ZRH in a 737-300.
Before the investigation could be completed, the incident had reached these pages, accompanied by lots of polemic "Problem rears its ugly head again"- etc. As this is a very sensitive subject, I didn't want to comment until sure of my facts. maybe now is the right time.
In my case, the rudder pedals were not displaced to the left (the direction in which the aircraft swung). The swing was sharp and of short duration. We were close to Vr and engine instruments were all OK (my first thought was a surge)- the ship was quickly under control and we took off.
I have to say that Boeing were super - organised an immediate telephone conference and asked many pertinent questions, as well as filling us in in great detail on the history of the problem, as well as possible failure modes. We pulled the flight recorder and had a read out made as soon as possible.
It turned out that the swing was visible on the recorder - the ship swung a couple of degrees (it felt like a lot more because it happened fast) and there was even a half degree of left bank shown as the left oleo compressed. The rudder position was straight ahead (as was the pedal position) and immediately the Yaw Damper corrected the swing with a kick to the right - ie. working as it should. We went through a list of other possible reasons and all we could come up with was a local atmospheric effect - possibly caused by a slight quartering tailwind being deflected by a small forest.
In my case, the ship was not to blame. Before any result could be obtained however, it had received bad press. The tendency is to put incidents into neat pre-conceived categories and apportion blame with too little knowledge sometimes. I hope this helps to put the record straight, as far as the ZRH incident was concerned.
The rudder itself, Thrust assymetry (short pop or otherwise) Dragging Brake, Yaw Damper input, Atmospheric condition (wake or general) Other flight control assymetry.
As did 'L337', so did I experience a sharp swing on T/O about a year and a half back. It happened in ZRH in a 737-300.
Before the investigation could be completed, the incident had reached these pages, accompanied by lots of polemic "Problem rears its ugly head again"- etc. As this is a very sensitive subject, I didn't want to comment until sure of my facts. maybe now is the right time.
In my case, the rudder pedals were not displaced to the left (the direction in which the aircraft swung). The swing was sharp and of short duration. We were close to Vr and engine instruments were all OK (my first thought was a surge)- the ship was quickly under control and we took off.
I have to say that Boeing were super - organised an immediate telephone conference and asked many pertinent questions, as well as filling us in in great detail on the history of the problem, as well as possible failure modes. We pulled the flight recorder and had a read out made as soon as possible.
It turned out that the swing was visible on the recorder - the ship swung a couple of degrees (it felt like a lot more because it happened fast) and there was even a half degree of left bank shown as the left oleo compressed. The rudder position was straight ahead (as was the pedal position) and immediately the Yaw Damper corrected the swing with a kick to the right - ie. working as it should. We went through a list of other possible reasons and all we could come up with was a local atmospheric effect - possibly caused by a slight quartering tailwind being deflected by a small forest.
In my case, the ship was not to blame. Before any result could be obtained however, it had received bad press. The tendency is to put incidents into neat pre-conceived categories and apportion blame with too little knowledge sometimes. I hope this helps to put the record straight, as far as the ZRH incident was concerned.
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FWIW one of the Seattle TV stations reported the UA578 incident as being caused by a 'wire brush' tool left by mtx somewhere in the run. I find no reference to this on the NTSB site, so it may just be typical media er.. reporting. Any AME care to comment on how likely is this scenario ?
