Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
No Power To Landing Gear Doors?  
User currently offlineDColeMAN From United Kingdom, joined Nov 2004, 274 posts, RR: 10
Posted (9 years 5 months 2 weeks 3 days 11 hours ago) and read 3146 times:

Hi all,

A couple of times I've seen aircraft arrive with the landing gear doors down as though there's no power to them and they're (in a way) just hanging there in the retracting and extending position. I wanted to ask is this always due to a hydraulics failure? Sometimes the aircraft has just taxied to the gate as normal and others have requested a full emergency landing because of this. Also, what causes this to happen?

Here are a couple of examples of what I'm reffering too -


View Large View Medium
Click here for bigger photo!

Photo © T Silgrim
View Large View Medium
Click here for bigger photo!

Photo © Luis Gonçalves



Thanks in advance,

Dale


Topless Women Drink 4 Free
8 replies: All unread, jump to last
 
User currently offlineLimaFoxTango From Antigua and Barbuda, joined Jun 2004, 808 posts, RR: 2
Reply 1, posted (9 years 5 months 2 weeks 3 days 11 hours ago) and read 3122 times:

Most likely, it's a hydraulic problem. A possible cause is maybe the hydraulic pump that operates the gear doors have failed or maybe there was a break in the hydraulic line that leads to the doors.


You are said to be a good pilot when your take-off's equal your landings.
User currently offlineDH106 From United Kingdom, joined Jun 2005, 626 posts, RR: 1
Reply 2, posted (9 years 5 months 2 weeks 3 days 11 hours ago) and read 3119 times:

When the hydraulic system that extends/retracts the gear fails the back up system to extend the gear is usually just a 'free fall' system where the gear's uplocks are removed and the gear just 'drops' into position under gravity and locks. The doors in this case are unpowered and remain open.


...I watched c-beams glitter in the dark near the Tanhauser Gate....
User currently offline320tech From Turks and Caicos Islands, joined May 2004, 491 posts, RR: 5
Reply 3, posted (9 years 5 months 2 weeks 3 days 10 hours ago) and read 3093 times:

I beg to differ with LimaFox Tango. There is no hyd pump that specifically operates the doors.

I don't know about 757's (I'm sure it's the same), but on Dash-8's and A320's, when the aircraft lands with the gear doors down, it means the pilots have used the alternate gear extension. On the Dash-8, if a snag develops in the landing gear extension system, a caution light, "LG Unsafe" illuminates. The usual cause is either a Prox Sensor Electronic Unit (PSEU, the computer that controls the LG, amongst other things) failure, or a valve failure. The result, if you insisted on using normal extension, would be to have the doors fail to open in sequence, thus possibly jamming the gear. I've seen several Dash-8 snags like this.

I haven't seen any A320 snags, but it's probably not much different.

In the Dash, the pilot first opens a small overhead panel, which is connected to a bypass valve by a cable. He then pulls on a handle that's under the panel. The first notch opens the MLG doors, the second notch drops the gear by gravity. The nose gear is extended the same way, using a panel and handle on the floor.



The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.
User currently offlineB744F From Germany, joined Jan 2006, 0 posts, RR: 0
Reply 4, posted (9 years 5 months 2 weeks 3 days 9 hours ago) and read 3080 times:

Quoting DColeMAN (Thread starter):
Here are a couple of examples of what I'm reffering too -

That caption with the Monarch picture is pointless. "can you guess?" What is the point of this rhetorical comment?


User currently offlineNKP S2 From United States of America, joined Dec 1999, 1714 posts, RR: 5
Reply 5, posted (9 years 5 months 2 weeks 3 days 7 hours ago) and read 3040 times:

Quoting 320tech (Reply 3):
There is no hyd pump that specifically operates the doors.

Well actually on the 757, there sorta' is. A DC motor driven pump will extend the doors and unlock the gear during alternate extension. Actually, when opening the L/G doors on the ground for maintenance, you hit a momentary contact switch that operates the pump. It will run till a pressure switch is satisfied.

Based upon the photo taken above, I'd say one of two things are occuring:

1) The L/G are lowered but the picture was snapped at the instant just before the sequence where the L/G doors shut.

2) The L/G was lowered via alternate extension due to some problem, and the A/C will land with the doors open.


User currently offlineNewark777 From United States of America, joined Dec 2004, 9348 posts, RR: 29
Reply 6, posted (9 years 5 months 2 weeks 3 days 5 hours ago) and read 2999 times:

That caption with the Monarch picture is pointless. "can you guess?" What is the point of this rhetorical comment?

It's a cheap attempt to get people to click on the photo, along with the "look more closely" part. You see that a lot in the db.

Harry



Why grab a Heine when you can grab a Busch?
User currently offlineHAWK21M From India, joined Jan 2001, 31712 posts, RR: 56
Reply 7, posted (9 years 5 months 2 weeks 3 days 2 hours ago) and read 2966 times:

Quoting Newark777 (Reply 6):
That caption with the Monarch picture is pointless. "can you guess?" What is the point of this rhetorical comment?

It's a cheap attempt to get people to click on the photo, along with the "look more closely" part. You see that a lot in the db.

Ways & Means of getting their Pics Viewed.
regds
MEL



Think of the brighter side!
User currently offlineDColeMAN From United Kingdom, joined Nov 2004, 274 posts, RR: 10
Reply 8, posted (9 years 5 months 1 week 2 days 13 hours ago) and read 2726 times:

Thanks to all who replied for your input.

Dale



Topless Women Drink 4 Free
Top Of Page
Forum Index

Reply To This Topic No Power To Landing Gear Doors?
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
737's, No Landing Gear Doors? posted Thu Dec 9 2004 01:17:49 by Sspontak
Landing-Gear Doors Failing To Open For Landing posted Tue Jan 20 2004 22:19:58 by Thrust
Why No Main Landing Gear Doors On The 737? posted Sat Sep 23 2000 22:57:00 by Starship
When To Deploy Landing Gear? posted Fri Jul 8 2005 20:35:22 by Goinv
Main Gear Wheels As Part Of Fuselage.No Gear Doors posted Wed Aug 7 2002 01:15:56 by Jgore
All Landing Gear Able To Be Turned On Crosswind? posted Wed Jun 6 2001 22:08:04 by Soku39
Landing Gear Failure posted Sun Sep 10 2006 16:12:48 by A320ajm
A380 Main Landing Gear posted Mon Jul 17 2006 05:30:09 by WingedMigrator
MD-80 Landing Gear posted Thu Jun 1 2006 18:52:52 by B737200
Aircraft Landing Gear Wheel Allignment posted Thu May 11 2006 14:07:40 by IsuA380B777

Sponsor Message:
Printer friendly format