gear down
 

somewhile ago i watched a britannia b757 take off from 09 at brs,his landing gear stayed down 4 a lot longer than normal.found out it was a warm/hot wheel and the crew elected too carry on and cool the wheels off in the air,what would happen if the gear failed too retract on command?is there a manual override and would the fuel consumption go up rapidly.would this be declared as a major emergency?many thanks in anticipation

The gear may be left down for several reasons.

On the A300, if you have an anti skid fault or a brake inoperative (allowable but with performance penalties) the gear is left down for 1 minute to allow the affected wheel to stop rotating before retraction.

If there are hot brakes due to a long taxi or a lot of braking due to a light A/C or downhill taxiway to the runway, then the gear may be left down until the temperature reduces. (we do have a max. temp. for the start of the take off roll). Was it a 09 departure fros BRS?

If the gear will not retract due to a failure, the fuel burn will be about 2.5 times the normal amount.
This will not be an emergency but unless the sector is short, say Bristol to Cardiff, then a return to land or divertion will have to be made.

Hope this helps.

Just read your post again. I see it was 09!

After taking off from a slushy runway it's normal to leave the gear down longer than normal to allow the slush to be blown off of the gear before retracting it. Prevents problems with the stuff freezing during the flight.

Gear not coming up isn't a huge, thing happens from time to time for a number of reasons such as gear pins left in (red faces all round, but easy and quick to fix)

Gear not coming down on the other hand...

Operation with the gear retraction system inop requires that the down lock pins be installed. Therefore even a short sector would be in violation of the AFM. In other words, if you select gear up and it stays down you return to base.

Yes there is a manual override it will bring up the gear, it's a trigger switch on the gear handle.

Yes, the fuel consumption would go up greatly with all that "stuff" hanging out there.

No, not a major (whatever that is) one if the gear won't come up you know it will stay down so you just make an overweight landing.......well at least that's what I'd do, I've had the pleasure of having a hung gear and making an overweight landing (but not at the same time).

Standing by to be corrected by my peers...... ;)

glhcarl.

Not sure why a diversion would be in violation of the AFM.

If you take off and gear does not come up the QRH (check list) on the A300 says refer to FCOM special operations if no immediate turn back.

Had this once out of Shannon going to Dresden. We diverted to Stansted where we had maintenance. No big deal, just monitor fuel flow to calculate range and consider things like icing.

The override on the A300 is not to be used in flight. If the gear will not come up normally, leave it down. If a bogie is not level, strut not fully extended or steering not centered, you don't want it jamming in the bay!

This could really spoil your day.

Safe flying,

Dixi.

Can I ask a separate but related question? When you select "gear down" on the approach, the lights turn green to indicate the gear is down and locked, right? Well I wondered how you know (apart from those lights) that the gear is indeed down because you obviously can't see it? What if the lights malfunctioned, how would you know it isn't safe to land? Is there a secondary system? Thanks in advance.

Care to elaborate?

After you've selected Gear Down and you don't get 3 greens it's either, Gear not locked down or bulb/power failure.

QRH says if no 3 greens wait 40 seconds and if no EICAS messages or gear door lights illuminated (the amber ones near the greens) then you can assume it's the bulb.

However, within 40 seconds you can expect a Gear Disagree EICAS with a checklist that directs you the appropriate action (including operation of the alternate system.)

As a final belt and braces you get a Configuration warning (v loud alarm + Red lights + Red EICAS message) if either thrust lever closed and the Gear isn't down below 800ft RA or with the flaps in the landing position.

Brits, hasn't been Brits for ages.

Phew, I thought I was in a Back to the Future film there!!

Nicholas 49.

The A300 has 2 sets of landing gear warning lights operated by independant electrical circuits.
If both these fail then there are indicator pins that protude from the upper surface of the wing. These are mechanically linked to the down locks, so one of the crew members goes back and looks out of the window.(can't do that on our freighters if we have a full load)
There is also a little peephole in the avionics compartment below the cockpit floor to see if the nose landing gear is locked down.

Most older aircraft have this sort of arrangement.

Cheers, Dixi.

sickBocks and dixi188 - thanks very much for the informative replies. Much appreciated.

Nick

That hit the nail on the head, and welded it. :O