Emergency Gear Extension

[Fly Boomer]

Reading one of Tom Turner's newsletters from his excellent Mastery Flight Training email blast, I learn that the Bonanza, and perhaps other retracts may not fully extend the gear when running off battery alone after a failure of the engine or charging system:

https://mastery-flight-training.com/wp-content/uploads/2023/05/2023.0525-FLYING-LESSONS.pdf

Can I engage the emergency gear extension mechanism in a 252 after a battery-only electric extension at 24 volts (or perhaps much less) if I want to be certain that it's as down as it would have been with the alternator pumping out 28 volts?

[N201MKTurbo]

If you get a green light, its down.

[A64Pilot]

If it’s like my J and if I understand the system the Emergency gear extension is fully operational with zero electrical supply, in fact I believe step 1 is to remove electrical power.

My C-210 was the same way, it would operate without any electrical power, however if there wasn’t fluid from a blown O-ring or hose, your not getting them down.

The Bo has an Emergency back up too.

However checking the manual gear extension indicator every time is important, not just put the switch down

[Fly Boomer]

1 minute ago, A64Pilot said:

If it’s like my J and if I understand the system the Emergency gear extension is fully operational with zero electrical supply, in fact I believe step 1 is to remove electrical power

Pull the breaker would be the first step.  I'm just trying to visualize starting the emergency extension from a mostly-extended state.

[A64Pilot]

3 minutes ago, Fly Boomer said:

Pull the breaker would be the first step.  I'm just trying to visualize starting the emergency extension from a mostly-extended state.

I don’t think it’s a bit different, except you don’t pull the cord much

On edit, hopefully there isn’t a mechanical jam, if there is I’d try putting the latch back in and trying to raise and re-extend, maybe get lucky

[Fly Boomer]

3 minutes ago, A64Pilot said:

I don’t think it’s a bit different, except you don’t pull the cord much

On edit, hopefully there isn’t a mechanical jam, if there is I’d try putting the latch back in and trying to raise and re-extend, maybe get lucky

In this scenario, there is nothing wrong with the mechanicals, just low voltage.  I think you are right about not pulling the cord much.  The mechanism should work the same starting from fully retracted or mostly-extended.

[Hank]

1 hour ago, Fly Boomer said:

Pull the breaker would be the first step.  I'm just trying to visualize starting the emergency extension from a mostly-extended state.

This happened to me once. I dropped the gear inbound over the VOR, just below the deck, and turned on the landing light. Blooey! Total electrical failure. My emergency extension is 52 cranks on the left side wall, but this time it only went 7 or 8 turns. The floor indicator showed GEAR SAFE in nice white writing on a green background, so I landed.

Checking the floor indicator on final has always been my practice, ever since I bought the Mooney.

[N201MKTurbo]

The Mooney gear system is different than most. If the green light comes on it is down and there is nothing else to do. I'm not familiar with the Bonanza system. I did work on the gear system on a Piper Saratoga recently, its green lights are controlled by switches on the overcenter links. The hydraulic pump shuts off when it gets to some pressure ~1500 PSI I think. Its emergency system just releases hydraulic pressure and lets them free fall by gravity. 

With the Mooney system, if the green light is on and you crank it some more, you could damage the gear system.

[Fly Boomer]

1 hour ago, Hank said:

Checking the floor indicator on final has always been my practice, ever since I bought the Mooney.

Because of the mechanical nature of that indicator, I trust it.  I guess if I had an engine failure or total electrical failure, if the battery had enough juice to make that floor indicator line up, I might not worry whether it was all the way down.  This might be something that can happen to a Bonanza, but not a Mooney.  Tom Turner is primarily a Bonanza guy, but writes about safety issues that affect us all.

[Hank]

54 minutes ago, Fly Boomer said:

Because of the mechanical nature of that indicator, I trust it.  I guess if I had an engine failure or total electrical failure, if the battery had enough juice to make that floor indicator line up, I might not worry whether it was all the way down.  This might be something that can happen to a Bonanza, but not a Mooney.  Tom Turner is primarily a Bonanza guy, but writes about safety issues that affect us all.

The floor indicator isn't electric. In my C, it's painted on the gear mechanism, with a hole in the floor to see it.

[Pinecone]

I had a complete electrical failure in a T-34.  I was coming back to my field with my friend's T-34.  Springfield Mass to NE MD.  About 1 minute after I had descended out of the solid IFR, poof, not electricity at all.  And ALL the instruments were electric.  A few minutes earlier and I would not be here.  I cranked the gear down and was VERY happy the gear indicators in the T-34 are mechanical.   Master relay shorted out and cut all power.

From what I understand of the Mooney gear, if it partially extends, the emergency will work fine to get it the rest of the way down.  And that floor manual gear indicator is a VERY GOOD THING.

[1980Mooney]

2 hours ago, N201MKTurbo said:

The Mooney gear system is different than most. If the green light comes on it is down and there is nothing else to do. I'm not familiar with the Bonanza system. I did work on the gear system on a Piper Saratoga recently, its green lights are controlled by switches on the overcenter links. The hydraulic pump shuts off when it gets to some pressure ~1500 PSI I think. Its emergency system just releases hydraulic pressure and lets them free fall by gravity. 

With the Mooney system, if the green light is on and you crank it some more, you could damage the gear system.

 

18 minutes ago, Hank said:

The floor indicator isn't electric. In my C, it's painted on the gear mechanism, with a hole in the floor to see it.

 

1 hour ago, Fly Boomer said:

Because of the mechanical nature of that indicator, I trust it.  I guess if I had an engine failure or total electrical failure, if the battery had enough juice to make that floor indicator line up, I might not worry whether it was all the way down.  This might be something that can happen to a Bonanza, but not a Mooney.  Tom Turner is primarily a Bonanza guy, but writes about safety issues that affect us all.

You are exactly right.  Due to the mechanical nature of the Mooney design, if the marker that you can see thru the window in the floor is lined up then the gear are down - the actuator jackscrew  is retracted, the shaft has turned, the bell cranks are over center and there is preload on all 3 gear.  It doesn't matter if the green light is on or not or burned out.    That is the simplicity and beauty of the Mooney design.  Mechanically all 3 gear move together - if the shaft has rotated and the mark lines up then all 3 are down. (see shaft rotating in the second video)

Tom Turner should have stuck to what he knows - Bonanza's.  

 

 

[N201MKTurbo]

Yes, if you have no electricity, crank it down till the lines line up, but if you do have electricity you want to stop when the green light lights up. The lines should be lined up at that point. If you stop when the green light comes on, you will have exactly the same preload as when using the electric actuator. You shouldn't go beyond that point. The green light should be your primary indicator. You can double check with the floor indicator, but you should only use that as your primary indicator, of when to stop, if the green light doesn't work.

[PT20J]

The emergency gear extension on the Mooney turns the gearbox the same as the motor so it is the same as lowering the gear electrically as far as the mechanics are concerned. If for some reason the gear is not fully down, you would use the emergency gear extension system to fully extend it. Whenever using the emergency system be careful to STOP when the light comes on and/or the floor indicator marks line up. If you keep actuating the system after that, you can jam it up.

[Ragsf15e]

3 hours ago, Hank said:

The floor indicator isn't electric. In my C, it's painted on the gear mechanism, with a hole in the floor to see it.

Mine is like that too but also has a light that comes on underneath the floor indicator when the gear is down.  Does your C not have a light under the floor indicator?

[Hank]

Just now, Ragsf15e said:

Mine is like that too but also has a light that comes on underneath the floor indicator when the gear is down.  Does your C not have a light under the floor indicator?

There's a light that shines in there when the cabin lights are on. When the lights are off, that one is too.

[Ragsf15e]

9 minutes ago, Hank said:

There's a light that shines in there when the cabin lights are on. When the lights are off, that one is too.

Interesting.  Mine has that light separate from the cabin lights.  It comes on when the gear is fully down and makes it easier to see the indicator window.

[PT20J]

24 minutes ago, Ragsf15e said:

Interesting.  Mine has that light separate from the cabin lights.  It comes on when the gear is fully down and makes it easier to see the indicator window.

Is yours on all the time or just when the gear is down. On the M20J, the light is on whenever the gear is down and off otherwise. It doesn't matter what the state of any other lights is. 

[Ragsf15e]

17 minutes ago, PT20J said:

Is yours on all the time or just when the gear is down. On the M20J, the light is on whenever the gear is down and off otherwise. It doesn't matter what the state of any other lights is. 

Yes, mine is like that too.  It’s only on when the gear is all the way down.  It works regardless of the cockpit lighting settings as well.  It sounds like @Hank only works with cockpit lighting on?

[Hank]

2 hours ago, Ragsf15e said:

Yes, mine is like that too.  It’s only on when the gear is all the way down.  It works regardless of the cockpit lighting settings as well.  It sounds like @Hank only works with cockpit lighting on?

Honestly, I don't think I've looked at it with the gear up . . . .

[A64Pilot]

On 5/26/2023 at 10:40 PM, Hank said:

Honestly, I don't think I've looked at it with the gear up . . . .

I have, the light is off and I think it’s red, not sure about the red part but I think it is

[Hank]

30 minutes ago, A64Pilot said:

I have, the light is off and I think it’s red, not sure about the red part but I think it is

The Unsafe mark is red; the Safe mark is green; in between is a red-and-white barber pole. The light is white.

[N201MKTurbo]

I think they changed that behavior over the years, so they may not all be the same.