A two legged Arrow ? what would happen?

[OldHand]

Can any of you QFI types give me an idea as to what would probably happen if one main leg of an Arrow failed to extend?

How could it happen?

What would be the best action for the pilot to take?

I recall an incident where one leg did just that and the pilot tried to re-cycle the gear, probably hoping to land with all the gear retracted but not only did the stuck leg fail to extend, but the extended leg failed to retract. The result was messy but thankfully bloodless.

What would YOU guys do?

[Tinstaafl]

Manufacturers procedurers for a manual extension & stuck u/c are my 1st actions.

I'd generally expect to do something like:

Manufacturer's drills including tryingyawing/pitching etc to shake the gear lose & recycling the gear.

Give a pan or mayday call. Brief & reassure my pax.

If forced to make 1 main + nosewheel landing I'd burn off as much fuel as possible (leaving sufficient reserves for a go-round under the prevailing conditions eg VFR or IFR etc).

If possible have the only rear pax (if there is only 1) sit on the side that the functioning main gear is on to offset any mass to the good side.

Choose long, firm grass or sealed, preferably with a good head wind. If a crosswind then the crosswind from the 'good' maingear side.

Land with max flap & at low a speed as possible. Hold the failed gear side off the runway for as long as possible until it sinks to the runway. Be prepared to go around until:

Once in the landing roll & committed to holding the failed wing off the rwy. cut fuel/mixture/ignition/master.

Only had a gear failure once but was able to reset the circuit breaker which the completed the retraction & then pump the gear down (it was in a Cessna). Bit disturbing that it was on my CPL flight test though

[This message has been edited by Tinstaafl (edited 14 December 2000).]

[A and C]

I,v been around to clear up the mess after two of these mishaps and i think that the post above has a lot of good things to say ,the only thing that i would take issue with is that i think it is better to land on a hard surface rather than grass as directional control can be maintained to a lower speed with the good wheel brake this slows the aircraft more quickly and surprizingly the hard surface damages the aircraft less than the grass.

Both times i have seen this the gear failed to free fall after a hydrulic power pack faiure because of lack of lubrication in the main trunuon (spelling ?) bearing and once on the jacks and properly lubricated the gear worked without a problem.

In my opinion the problem stems from the fact that to get at the grease niples you have to have a right angle grease gun and a lot of hassel to get it on to the grease niple when laying on your back or you have to jack up the aircraft and half retract the gear to get the grease niple to rotate to a position that a normal grease gun will do the job.
I prefer the second option as when the aircraft is jacked up i do a quick free fall check.
In short i think that the lubrication gets forgoten and the problem is masked by the gear powering down.......untill the power fails.

[CaptainAirProx]

I agree with A & C, but I would like to go one further.

If one gear (main) will not extend, first of all go to an airfield with "proper" emergency services. Then if grass land gear up (all up), if tarmac land with remaining gear down. If the wing digs in on grass, ouch!

Personally if I am landing on grass with failed gear of any sort, I would land gear up everytime. The Arrow I fly often had a gear up landing by mistake, no damage except for prop. The Piper has runners underneath just for that mistake.

I have had several gear probs on Arrows and Senaca's (same gear system). One thing I would say is don't do the emergency free fall until you have tried other avenues and had the gear inspected by a fly-by.

One time all my gear stuck half way. My concern was if I tried free fall - A) it was stuck; B) free fall works best from starting fall when fully up. Therefore if motor will get gear back up do that before doing free fall. As it happenened motor was worn out.

[Bear Cub]

How about setting the aircraft up for a landing deep into the runway length...then shutting down the engine and gliding the last few hundred yards.

Hold the controls to keep the affected "third" of the aircraft from striking the ground until just short of stalling speed - then deliberately lower the affected area to make ground contact whilst having positive control.

This could save a propeller replacement, a CSU replacement and an engine replacement.

Just a thought...any comments?

And...as the original question suggests nose wheel and one main have extended and locked...would it be prudent to land at the edge of the runway...keeping nose wheel and main leg on the hard stuff but the "soon to be scratched" wingtip over the grass?

------------------
Hunting is bad!!
Support the right to arm Bears!!

[Tinstaafl]

The reason for choosing a sealed RWY is for the lack of friction or any sod/clods to cause the tip to dig in.

I had in mind a firm, short dry grass RWY in my post above ie not a long grass or soft or wet unsealed RWY.

Fairly common in Oz. Probably not so in the UK! :).

Bear Cub You lose the option for a go round in that case. I would prefer to keep the go-round option until I'm in the landing roll & then shut down.

Also there is no guarantee that the prop will stop in a position that will prevent contact with the ground once the wing hits.

Most props seem to stop away from the horizontal. Some nice engineers even make sure the prop is bolted on in such a position to aid hand swinging.

[Bear Cub]

Tin...correct...no option of a go-around - but if you have already passed "commital height" it isn't an option anyway...so why not save some money.

Agree with you 100% about the darned prop not stopping horizontal (I've often wondered why it never does - and I've worked at a place where the prop angle was a signal to the refuellers to come and top it up [after fuelling, they turned the prop to the horizontal and then knew it was full]) - but you can "kick it round" with the starter.

I agree with your comments - but still believe you could save a lot of money and engineering work with a bit of effort and thought.

[Tinstaafl]

What sort of committal height do you like to use in an Arrow?

An approach committal height in an asymmetric light twin I understand since the startling lack of performance in the landing configuration will probably involve a loss of altitude until reconfigured 'clean'.

For an Arrow (& other singles) I opt for readiness for a go-round at any time - including wheels on the ground if I think it's appropriate. I've certainly had enough students cause the need, even after touchdown.

[Richard Bristowe]

One of the problems with an Arrow is that the nose u/c extends forwards, i.e. against the slipstream. Altho' the POH says it will extend in emergency free fall at 87kts you may find you have to come down to 70 kts to make it work. What happens is that the slipstream retards the nose u/c but it is usually one of the main u/cs that doesn't lock down as a result of the forces on the nose leg.

[A and C]

Just a few comments first i,v tryed stopping the engine just as you come over the hedge and the prop will not untill the speed is down to about 25kts due to inertia and windmilling if your luck is in the prop may not strike the ground ,forget trying to crank it horizontal you have more important things to do in that 20 seconds.

I cannot see how the nose gear can retard the main gear once it is locked down ,the freefall for the PA28R gear works by releasing the hydrulic fluid from the UP side of the retraction jack and letting fluid into the down side side of the jack as the leggs start to drop they may be retarded by the high demand for fluid to the down side of the jack but this affects all the legs the reason for main legs not locking down after free fall is lack of bearing lubrication as i described in my last post on this subject.

[Horsepower]

Agree with most of the above.

Hard runway is best in this situation. For the reasons outlined by A and C, extending the gear by freefall can be a real bu$$er and I’ve spent some long, sweaty minutes yawing and pitching like a pilot with Parkinson’s to get three greens at foolishly low airspeeds.

Chopping the engine before landing is simply not on; the last thing on my mind in a situation like this would be the cost of replacing the prop/CSU/engine—walking away to the pub is the aim of the game.

HP

[Richard Bristowe]

Sure, A and C, if it is locked, but if in free fall Newton's laws come in to play. Having experimented at length with P28R on jacks and utterly free and lubed u/c I can confirm that minor restriction to the forward travel of the nose u/c (such as that given by airflow) has the effect of preventing one main from locking.

[A and C]

RB the nose gear should allways free fall if it wont (at the book airspeed) then something is wrong ,lubrication is not normaly the problem as leaks from the engine normaly supliment the the grease that should do the job.
take a look at the bushes and bolts in the system for play and what is the state of the springs that hold the over center lock in place and do the flex hoses still flex after all these years ?

The system works well but only if it is looked after the problem is that most owners of these aircraft are new to retractable gear and are not prepaired for the extra expence.