Re: USAir 737 nose gear collapse

From:         rdd@netcom.com (Robert Dorsett)
Organization: Netcom Online Communications Services (408-241-9760 login: guest)
Date:         13 Apr 94 02:46:47 PDT
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In article <airliners.1994.1117@orchard.Chicago.COM> John Harvie <John_Harvie.LOTUS@notesteam.lotus.com> writes:
>
>USAir spokeswoman Andrea Butler said airline mechanics have determined that the 
>collapse was not due to mechanical failure. 

Yeah, right!


>She said airline investigators are 
>trying to determine whether human error -- such as someone pushing the wrong 
>button -- or some other factor was at fault. Butler said a routine maintenance 
>check on the jet was performed Tuesday night, and there were no problems.

The 737 has an electrical solenoid lockout on the landing gear lever.  It 
should not have been possible to lift the lever.  There is an override 
trigger.  However, the 737 nose gear is actuated by System A, which is 
provided by engine-driven pumps, and I doubt the gear would move under under
no power (they did say it was on the ground, 30 minutes before flight, right?).

If, however, the lockout override was used to move the lever to the OFF
position, the actuator valves would have opened, and there would have been
zero pressure, thus allowing external factors to move the airplane and 
thus "raise" the nose gear.


>to prevent such an occurrence. Also, related to the thread on engine mounts on 
>wings, could a 737 make a landing without nose gear the way the 727 was able 
>to? (It was quite a show on the local TV news.)

Probably; sometimes one doesn't have a choice, and the as-many-gear-down-
as-possible rule of thumb applies to 737s as much as to 727s.


Sounds to me like maintenance left the gear lever in off, and the crew hadn't
done the safety check yet.  

I sure do hope the captain's son was nowhere near the cockpit.  After the
FedEx hijacking last night, if this keeps up, it'll be impossible to get 
anywhere NEAR a cockpit.




--              
Robert Dorsett                                                       
rdd@netcom.com