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Gear-Up When On Ground. Is It Possible?  
User currently offlineJgore From Argentina, joined Feb 2002, 550 posts, RR: 2
Posted (12 years 1 month 4 weeks 1 day 3 hours ago) and read 3251 times:

is it possible ?

20 replies: All unread, jump to last
 
User currently offlineJT-8D From United States of America, joined Dec 2000, 423 posts, RR: 3
Reply 1, posted (12 years 1 month 4 weeks 1 day 3 hours ago) and read 3157 times:

If your talking about accidently retracting the gear, it should not be possible if the safety system is working correctly. On most airplanes, the gear handle is locked in the down position, if the weight is on the gear. It can be bypassed for maint purposes, but you better have the gear pins installed. If I didnt answer your question, post again..JT

User currently offlineJgore From Argentina, joined Feb 2002, 550 posts, RR: 2
Reply 2, posted (12 years 1 month 4 weeks 1 day 3 hours ago) and read 3138 times:

Yeah, it was very clear. but i was wondering if there had happened an accident when this sensor was deactivated.
thanks again

jgore  Smile/happy/getting dizzy


User currently offlineJT-8D From United States of America, joined Dec 2000, 423 posts, RR: 3
Reply 3, posted (12 years 1 month 4 weeks 1 day 3 hours ago) and read 3123 times:

Im sure it has, but I cant remember a case that Ive seen myself. It is definetly possible though. Example, on 737, if you are going to replace the first officers fmc cdu, the gear handle has to be move to the "off" position. This will not retract the gear, but will not pressurize it to the down position either. What if you accidently move the handle through the off position, and into the up position? Just apply this simple rule--If you are going to move the handle, put the stinking gear pins in. It takes 2 minutes to install the pins, it could take weeks to fix the crushed nose of an airplane if you dont..JT

User currently offlineH. Simpson From United States of America, joined Mar 2001, 949 posts, RR: 3
Reply 4, posted (12 years 1 month 4 weeks 1 day 2 hours ago) and read 3082 times:

i would be the very cool to see it, only if nobody was hurt!

User currently offlineZeke From Hong Kong, joined Dec 2006, 8643 posts, RR: 75
Reply 5, posted (12 years 1 month 4 weeks 1 day 2 hours ago) and read 3078 times:

Have a look for a post on a recent China Airlines 744F incident, gear up on the ground with photos.


We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlineJT-8D From United States of America, joined Dec 2000, 423 posts, RR: 3
Reply 6, posted (12 years 1 month 4 weeks 1 day 2 hours ago) and read 3078 times:

oops..JT

User currently offline737doctor From United States of America, joined Mar 2001, 1332 posts, RR: 40
Reply 7, posted (12 years 1 month 4 weeks 1 day 2 hours ago) and read 3073 times:

Squat switches should prevent this from happening, but gear pins are always the safest bet.


Patrick Bateman is my hero.
User currently offlineL-188 From United States of America, joined Jul 1999, 29705 posts, RR: 59
Reply 8, posted (12 years 1 month 4 weeks 23 hours ago) and read 3054 times:

There was a mechanic that got killed up here last winter when the gear on a Beech 99 folded when he was working on it.


OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
User currently offlineMetwrench From United States of America, joined Aug 2001, 750 posts, RR: 2
Reply 9, posted (12 years 1 month 4 weeks 23 hours ago) and read 3047 times:

Tech Rep can help with this one. Research a FACTS issue, about three years old regarding the Metro. I'll also look back, but this article, (News Letter issued by Fairchild) recapped two scenarios that caused nose gears to fold up on the ground. One of these cases caused a "Time Life" action to be created to limit the LDG control valve to have a Life Limit of 2500 hours, previously on condition.

As in any accident or incident, a long string of unfortunate events had to unfold before the misfortunes happened.


User currently offlineWhiskeyNovembr From , joined Dec 1969, posts, RR:
Reply 10, posted (12 years 1 month 4 weeks 20 hours ago) and read 3034 times:



Of course it's possible. Haven't you seen the Simpsons episode where Homer did it?



User currently offlineTechRep From , joined Dec 1969, posts, RR:
Reply 11, posted (12 years 1 month 4 weeks 19 hours ago) and read 3043 times:

To answer your question it is very possible it could happen but yet very unlikely. Statically, with no hydraulic power applied, WOFW through whatever means and pull the gear handle to the retract position will have no effect. Now apply hydraulic power in the above scenario, depending on size/weight of the aircraft the main gear's will not tract but your nose will in most cases.

This is pure speculation of course but it can be easily tested even within the confines of most maintenance manuals. GEAR PINS INSTALLED, hydraulic power applied, lifting the gear handle will test all hydraulic carriers on the retract side for leaks and handle down all hydraulics on the extension side. Now in either scenario go out while your testing this and move the gear pins back and forth but do not remove them. You will find probably your able not to move the nose gear pin but the main gear pins you probably can.

I remember in the Air Force these fighter pilots would lift the gear handle just before rotation. So when the aircraft rotated, they would pull immediately into a vertical climb. I watched this on occasions and sure enough the nose gear would retract but mains stayed down.

The most important factor to this, is weight of course, the more weight and resistance acting against the retract actuator, the less likely it will happen.

TechRep


User currently offlineJetCaptain From Canada, joined Dec 2000, 236 posts, RR: 1
Reply 12, posted (12 years 1 month 4 weeks 17 hours ago) and read 3015 times:

As one of my ground school instructers used to say:

"On the ground, the gear doesn't go up, the aircraft goes down."


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Photo © Kev hotchkiss



JC



User currently offlineFDXmech From United States of America, joined Mar 2000, 3251 posts, RR: 35
Reply 13, posted (12 years 1 month 4 weeks 14 hours ago) and read 2976 times:

NKP S2 and I both witnessed a PEX 737-100 down on its nose in EWR hangar 14.


You're only as good as your last departure.
User currently offlineNKP S2 From United States of America, joined Dec 1999, 1714 posts, RR: 5
Reply 14, posted (12 years 1 month 4 weeks 13 hours ago) and read 2969 times:

How've you been FDX? I hope all is well with you. Yeah, that was quite a situation at EWR wasn't it? A good reminder to never assume the last guy in the cockpit left everything in the cockpit configured correctly ( safely ). I'm sure glad I wasn't the one who turned the "B" pumps on. BTW: I still own the used 'Snap-On' roll-away I bought from the guy who DID throw the switch, when he left the company.

User currently offlineBjones From United States of America, joined Feb 2002, 123 posts, RR: 0
Reply 15, posted (12 years 1 month 4 weeks 13 hours ago) and read 2958 times:

I don't know of any other examples but the Air Force primary jet trainer the T-37 actually has an emergency gear override button. If you hold that button down you can move the gear handle up regardless of weight on wheels. In training they tell you to use it as a last resort to avoid contact with something like a building or other aircraft in the event of brake failure. You can also use it in the air if for example the gear handle won't raise because of a faulty squat switch and you need to get the gear up to make it to an alternate due weather or something. They say only to use it in the air as last resort too because the problem causing the gear handle not to raise may cause gear to jam in up position as well.

User currently offlineJsuen From United States of America, joined Aug 2001, 211 posts, RR: 0
Reply 16, posted (12 years 1 month 4 weeks 11 hours ago) and read 2932 times:

The MD-80s have a button. You can also pull the squat switch circuit breaker.


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User currently offlineJet-a gasguy From United States of America, joined Dec 2000, 266 posts, RR: 2
Reply 17, posted (12 years 1 month 4 weeks 10 hours ago) and read 2929 times:

I watched a 757 gear's retract while the aircraft was on the ground.........of course the aircraft was on jackstands. Really fascinating to watch up close. That day at United's SFO maintenance facility was truly the highlight of my last trip.

Jet-A gasguy
 Big thumbs up



Find a job you love, and you'll never work a day in your life.
User currently offlineJgore From Argentina, joined Feb 2002, 550 posts, RR: 2
Reply 18, posted (12 years 1 month 4 weeks 10 hours ago) and read 2921 times:

Would be great to watch that lading gear being tested on ground!!! hehehehehe

jgore  Smile/happy/getting dizzy


User currently offlineAaron atp From United States of America, joined Mar 2000, 533 posts, RR: 2
Reply 19, posted (12 years 1 month 4 weeks 10 hours ago) and read 2916 times:

Did anyone see the results of the ExecJet G-IV incident in Teterboro a while back?

The mains were BENT and of course the nose fell...

aaron


User currently offlineFDXmech From United States of America, joined Mar 2000, 3251 posts, RR: 35
Reply 20, posted (12 years 1 month 4 weeks 6 hours ago) and read 2884 times:

The MD80 as well as DC10 gear handle is prevented from being moved to "retract" by a mechanical anti-retraction mechanism. Though it can be overridden by the override button.

Pulling the squat switch c/b's will put many systems in the "air" mode but will not have an affect on the gear handle.



You're only as good as your last departure.
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