737 Rudder Desigh Fault
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Joined: Jun 2001
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From: Adelaide, South Australia
737 Rudder Desigh Fault
Does anyone know if Boeing has fixed the design fault with the 737 Rudder? How would existing 737 operating/emergency procedures deal with an abrupt, unplanned, right angled missalignment of the rudder on the approach.
Isn't that what happened to the Alaska flight that went into the drink?
Isn't that what happened to the Alaska flight that went into the drink?
Joined: Oct 1999
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From: To your left
Ah Catchpoint afew minor corrections.
Teh Alaskan aircraft was a DC-9 type derivative (MD-80 or similar) and appears to have lost its hoirizontal stabilizer after a trim screw jack failure allowing the whole assembly to pivot about its aft attach point and separate from the aircraft - nothing to do with 737 rudder failures.
The 737 rudder servo has undergone modification and there is a program to retrofit. Pilots have been trained and use procedures and techniques to overcome an upset caused by possible erroneous rudder inputs in the meantime.
Hope this helps.
Teh Alaskan aircraft was a DC-9 type derivative (MD-80 or similar) and appears to have lost its hoirizontal stabilizer after a trim screw jack failure allowing the whole assembly to pivot about its aft attach point and separate from the aircraft - nothing to do with 737 rudder failures.
The 737 rudder servo has undergone modification and there is a program to retrofit. Pilots have been trained and use procedures and techniques to overcome an upset caused by possible erroneous rudder inputs in the meantime.
Hope this helps.
Joined: Dec 2000
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From: London UK
737 operators have drills for dealing with a 'uncommnaded yaw or roll' or 'uncommanded rudder'. This involves using all available flight controls (ailerons and rudders) to maintain control of the aircraft. If necessary we will lower the nose to pick up airspeed (hence making the controls more effective).
Most operators also have an 'advanced manouevre program.' This involves a whole sim session of recovering from 'unusual attitudes'. Great fun! - and very useful too.
Part of the problem with one of the 'uncommanded yaw/roll' accidents (possible due to wake turbulence) was innapropriate recovery (not rolling wings level befpre attempting to pull out of the steep dive). This is something we are practised at.
There is certainly evidence of rudder hard overs in the past, but Boeing strongly deny much of the speculation and say it is perfectly safe.
Most operators also have an 'advanced manouevre program.' This involves a whole sim session of recovering from 'unusual attitudes'. Great fun! - and very useful too.
Part of the problem with one of the 'uncommanded yaw/roll' accidents (possible due to wake turbulence) was innapropriate recovery (not rolling wings level befpre attempting to pull out of the steep dive). This is something we are practised at.
There is certainly evidence of rudder hard overs in the past, but Boeing strongly deny much of the speculation and say it is perfectly safe.
Joined: Oct 1999
Posts: 464
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From: UK
TT,
The problem as I understand it is that the retrofit program for the rudder servo will take some years to ensure that all of the worlds 737's in service are dealt with.
In the meantime 10 knots have been added to flap speeds in the hope that that will help in controlling a rudder hard over.
It will still be a white knuckle ride for any crew having to deal with one.
The problem as I understand it is that the retrofit program for the rudder servo will take some years to ensure that all of the worlds 737's in service are dealt with.
In the meantime 10 knots have been added to flap speeds in the hope that that will help in controlling a rudder hard over.
It will still be a white knuckle ride for any crew having to deal with one.
Joined: Oct 1999
Posts: 224
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From: To your left
Flap 5,
I know and understand that the retrofit will take some time - we are talking a LOT of 737's out there.
Also, as I mentioned, the aircrew have been trained in procedures to overcome a rudder upset (yeah 10kts plus etc etc) - I never said it would be an easy procedure or that their pants wouldn't change colour when it happened!! 
I know and understand that the retrofit will take some time - we are talking a LOT of 737's out there.
Also, as I mentioned, the aircrew have been trained in procedures to overcome a rudder upset (yeah 10kts plus etc etc) - I never said it would be an easy procedure or that their pants wouldn't change colour when it happened!!
