737 rudder
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737 rudder
Hi there
I'm a 737-200 driver and as such am more than a little interested in the FAA's recent call for a new rudder system for the AC. I've been trying to understand the thinking behind the QRH procedure for "jammed or restricted rudder" and have a question I'm hoping someone out there can maybe answer. To wit:
In the event of a rudder hardover due to jamming of the servo
valve, will removing all hydraulic power alleviate the situation and
result in the rudder "slipstreaming"? The QRH calls for removing B
pressure from the main PCU and powering the standby PCU, then (if that
doesn't help) removing A pressure form the main PCU, and finally
removing B pressure from the standby PCU and leaving the rudder
unpowered. If the servo valve had jammed will the rudder now "unjam" or
is it stuck regardless?
Any thoughts welcomed.
I'm a 737-200 driver and as such am more than a little interested in the FAA's recent call for a new rudder system for the AC. I've been trying to understand the thinking behind the QRH procedure for "jammed or restricted rudder" and have a question I'm hoping someone out there can maybe answer. To wit:
In the event of a rudder hardover due to jamming of the servo
valve, will removing all hydraulic power alleviate the situation and
result in the rudder "slipstreaming"? The QRH calls for removing B
pressure from the main PCU and powering the standby PCU, then (if that
doesn't help) removing A pressure form the main PCU, and finally
removing B pressure from the standby PCU and leaving the rudder
unpowered. If the servo valve had jammed will the rudder now "unjam" or
is it stuck regardless?
Any thoughts welcomed.
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The Patna 737 was heavily into the stall buffet as a result of levelling (and subsequent speed dissipation) during an impromptu 360 turn on finals. I think it was also configured at the time. You do tend to get a bit of autorotative wing-rock at the stall - so I doubt that rudder hard-overs had anything to do with this accident.
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Who knows what evil lurks in the hearts of men?
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Who knows what evil lurks in the hearts of men?
Guest
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Dear Mulligan,
You asked, <In the event of a rudder hardover due to jamming of the servo
valve, will removing all hydraulic power alleviate the situation and
result in the rudder "slipstreaming"?>
The short answer is yes. But as 'Tcas Climb' says "Sounds like the procedure you have explained is time consuming. Did theese boys have time to do it?".
If you have a rudder hardover at below 'crossover' speeds the A/C is on it's back in a very short time. This will obviously be irrecoverable on the approach.
Regards
Exeng
You asked, <In the event of a rudder hardover due to jamming of the servo
valve, will removing all hydraulic power alleviate the situation and
result in the rudder "slipstreaming"?>
The short answer is yes. But as 'Tcas Climb' says "Sounds like the procedure you have explained is time consuming. Did theese boys have time to do it?".
If you have a rudder hardover at below 'crossover' speeds the A/C is on it's back in a very short time. This will obviously be irrecoverable on the approach.
Regards
Exeng
Guest
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You should note that the Boeing procedure for dealing with this has been heavily criticised by the ETEB, and a new procedure which pilots stand some chance of carrying out is to be introduced. Such a procedure is already available as part of a Boeing AD.
Boeing strike yet again, with unsafe aircraft and unsafe procedures.
Boeing strike yet again, with unsafe aircraft and unsafe procedures.
