Gear pins?
Guest
Posts: n/a
Gear pins?
Just wondering, what is the use of gear pins?
I have asked many pilots and none have come up with a really good answer. Some say it's to prevent gear retraction on the ground. What happens though is that if you forget the little suckers, they prevent gear retraction in the air! Those things will get you in trouble if the preflight wasn't done 100%.
So let's have a shot at it!
I have asked many pilots and none have come up with a really good answer. Some say it's to prevent gear retraction on the ground. What happens though is that if you forget the little suckers, they prevent gear retraction in the air! Those things will get you in trouble if the preflight wasn't done 100%.
So let's have a shot at it!
Guest
Posts: n/a
There are gear pins that will prevent accidental retraction of gear on the ground or during maintenance. The most common gear pins, however, deactivate the nose wheel hydraulics. If those were active, using a pushback rod would get rather interesting. Would the rod snap and go all over the place breaking handlers? When connecting or disconnecting the rod a pilot stretching his legs could make it flail about too, again breaking handlers. I would not have been amused if that had happened while I was working there.
Cheers,
/ft
Cheers,
/ft
Guest
Posts: n/a
Just wondering, what is the use of gear pins?
The pins are there, as you suggested, to stop accidental retractions on the ground, this is kinda embaressing to say the least. As you mention they will get you in trouble if you dont do a good preflight, but not as much trouble as a wheels-up on the ground.
If you do misthem, simply land again and sort it out.
Used to be a fairly regular happening on the mighty Fin!
The pins are there, as you suggested, to stop accidental retractions on the ground, this is kinda embaressing to say the least. As you mention they will get you in trouble if you dont do a good preflight, but not as much trouble as a wheels-up on the ground.
If you do misthem, simply land again and sort it out.
Used to be a fairly regular happening on the mighty Fin!
Guest
Posts: n/a
Thanks ft, didn't mean those pins though. The ground engineer takes care of that one, hopefully. I meant the ones that are in the retraction mechanism.
We have a ground interlock to prevent retraction on ground, don't we? I still don't see the advantages outweigh the possible disadvantages if you forget to take 'em out
We have a ground interlock to prevent retraction on ground, don't we? I still don't see the advantages outweigh the possible disadvantages if you forget to take 'em out
Guest
Posts: n/a
On the CV-880 & CV-990 a warning light illuminated on the F/E annunciator panel if any gear pin was inserted. Pity Boeing and other manufacturers didn't follow this design, as I was caught out once with a 747F having been positioned on the ramp by maintenance with all main gear pins inserted without streamers on them. The last item on our after start checklist was all gear pins removed, which was confirmed by the departure engineer on the ground. After dumping 63 tons of fuel, we returned for a landing. The ground engineers said sorry but this incident still haunts me!
Guest
Posts: n/a
HotDog, aargh! I've heard similar stories and it's pretty embarrassing, even if it wasn't really your fault. That's what got me wondering about the pins.
2DD, I don't think I'll be in the vicinity of an F50 any time soon, can you give me the scoop?
2DD, I don't think I'll be in the vicinity of an F50 any time soon, can you give me the scoop?
Guest
Posts: n/a
Iz, all answers given here are correct
Just to more precise, the pins do indeed prevent the landing and take-off gear(s) to retract when on the ground. All the biggies have hydraulic systems, which when on, maintain the locking cylinders of the gear(s) pressurized (not talking about the extension/retraction cylinder here, those are , on most aircraft, pressureless once the cycle is done). So, no hydraulic pressure, and the gear "could" retract, e.g. during the towing of the aircraft or when subjected to strong (gales) winds. The pins then also prevents engineers (or pilots under instruction ...) from selecting the gear to up by mistake.
Thanks for reading my pinch of salt...
------------------
... cut my wings and I'll die ...
Just to more precise, the pins do indeed prevent the landing and take-off gear(s) to retract when on the ground. All the biggies have hydraulic systems, which when on, maintain the locking cylinders of the gear(s) pressurized (not talking about the extension/retraction cylinder here, those are , on most aircraft, pressureless once the cycle is done). So, no hydraulic pressure, and the gear "could" retract, e.g. during the towing of the aircraft or when subjected to strong (gales) winds. The pins then also prevents engineers (or pilots under instruction
...) from selecting the gear to up by mistake.Thanks for reading my pinch of salt...
------------------
... cut my wings and I'll die ...
Guest
Posts: n/a
Nothing is 100% foolproof and as such so as to prevent inadvertant retraction an/or collapsing of gear when being towed gear safety pins must be installed. We also have a SOP when if the a/c is on the ground more than X hrs we have to put the pins in (reasons as detailed by fly4fud).
Although on our checksheets there is always a statement to check for removal of gear pins etc, if they have been installed I(we) always make an entry in the log that they are fitted, so that until somebody removes then stows them and clears the log the a/c can't effectively fly.
Of course nobody ever misses them on their walkaround do they!
A/C have taken off with them still in before and it will happen again!
Although on our checksheets there is always a statement to check for removal of gear pins etc, if they have been installed I(we) always make an entry in the log that they are fitted, so that until somebody removes then stows them and clears the log the a/c can't effectively fly.
Of course nobody ever misses them on their walkaround do they!
A/C have taken off with them still in before and it will happen again!
Guest
Posts: n/a
Hi,Iz.
The F50 has a notice on the gear,warning people not to push up on a particular beam.Legend has it that after an F50 suffered a gear collapse,a Fokker training guy pushed up on said beam whilst demonstrating to new trainees.Sounds of collapsing aircraft and collapsing career.
The pins are put in for towing,to prevent a bump causing the squat switchs to activate the retraction circuit.
regards
TDD
The F50 has a notice on the gear,warning people not to push up on a particular beam.Legend has it that after an F50 suffered a gear collapse,a Fokker training guy pushed up on said beam whilst demonstrating to new trainees.Sounds of collapsing aircraft and collapsing career.
The pins are put in for towing,to prevent a bump causing the squat switchs to activate the retraction circuit.
regards
TDD
Guest
Posts: n/a
Thanks a lot everybody! Appreciate the info.
Reboot, sorry to disappoint ya. Don't know why some people think I'm stupid for asking this. I've had discussions with various captains on this and many weren't sure either. So maybe they're stupid as well. Oh well.
I guess it would have been the most stupid if I walked around not knowing the facts and not willing to ask anyone.
Reboot, sorry to disappoint ya. Don't know why some people think I'm stupid for asking this. I've had discussions with various captains on this and many weren't sure either. So maybe they're stupid as well. Oh well.
I guess it would have been the most stupid if I walked around not knowing the facts and not willing to ask anyone.
Guest
Posts: n/a
A use that the engineers have for the gear pins is tracing a hyraulic leak in the retraction mechanism. If the leak is in the retraction lines, then these will not be pressurised until the aircraft is airborne, gear selected up, and the leak presents itself, albeit with no one present. So install gear pins, and select gear up. (Its nerve wracking!) The up lines are then pressurised, and you can then check for leaks.
Seen it done.
CCCCC......ough
Seen it done.
CCCCC......ough