Delayed Gear Extension

[A64Pilot]

At first I thought it was just my perception, but it’s happened a few times. Place the gear switch to down, and there is a several second delay before the gear begin to come down.

‘It’s intermittent, usually the gear starts down as soon as I put the switch to down, I delay gear extension until I get into the white arc, so the only real indicator of gear in transit to me is the gear unsafe light, but today coming back from Breakfast it seemed there was a four of five second delay between selecting the switch to down and it starting down.

‘Anyone heard of this before? Once they start down they come down at the same speed, it’s just a delay in starting.

81 J Model, 2200 airframe hours 

Edited April 4, 2021 by A64Pilot

[carusoam]

Not a common misbehavior...

Got any jacks in the hangar?

Things to find...

• Gear Switch
• Airspeed or squat switch
• relay
• motor
• Limit switches...

Sounds like something wants to get warmed up before it works properly...

With the change in temperature... squat switches start behaving differently with donut health...

Do you have any amperage data while this is going on?  In case the motor is trying to overload?

PP thoughts only, not a mechanic...

Best regards,

-a-

[N201MKTurbo]

Mine did that,

A quick test is to stomp on the floor board right in front of the pilots seat if it won’t go down. If that makes it go down, you need a new gear contractor.

[A64Pilot]

gear contactor, is that a relay?

[Ragsf15e]

I have also seen this.  Mine has also done this before coming up.  I actually called Dmax and talked to him about it.  He suggested cleaning and exercising the limit switches in the belly.  I did and it hasn’t happened again. Maybe one is sticking?  However, could just be waiting to happen again soon as it was an intermittent issue.

 

Edited April 5, 2021 by Ragsf15e

[N201MKTurbo]

7 hours ago, A64Pilot said:

gear contactor, is that a relay?

Yes, the big ones that look like starter solenoids Next to the actuator.  
 

They are bolted to the bottom of the floorboards. They get stuck. The vibrations of the plane shakes them loose. You can knock them loose by stomping on the floor.

Edited April 5, 2021 by N201MKTurbo

[A64Pilot]

4 hours ago, N201MKTurbo said:

Yes, the big ones that look like starter solenoids Next to the actuator.  
 

They are bolted to the bottom of the floorboards. They get stuck. The vibrations of the plane shakes them loose. You can knock them loose by stomping on the floor.

What I thought you were saying, Is it item number 48 in the attached photo’s? if so source of supply? where do I get one? Are there two, one up one down?

[A64Pilot]

9 hours ago, Ragsf15e said:

I have also seen this.  Mine has also done this before coming up.  I actually called Dmax and talked to him about it.  He suggested cleaning and exercising the limit switches in the belly.  I did and it hasn’t happened again. Maybe one is sticking?  However, could just be waiting to happen again soon as it was an intermittent issue.

 

I’m going to have to get a look at these too I guess, from what I can tell in the logbook other than greasing and changing donuts once, there has never been anything done to the gear.

How much weight is needed to hold the tail down? I’m thinking washtub on wheels full of concrete, or is there a better way?

[Hank]

Just now, A64Pilot said:

I’m going to have to get a look at these too I guess, from what I can tell in the logbook other than greasing and changing donuts once, there has never been anything done to the gear.

How much weight is needed to hold the tail down? I’m thinking washtub on wheels full of concrete, or is there a better way?

That works well. Or you can put a couple cases of oil on the horizontal stab, up close to the vertical stab.

[N201MKTurbo]

You can take the empty weight of the plane and multiply it by the CG arm ahead of the jack points over the arm from the jack points to the tail hook to determine how much weight you need. I would figure this with a pilot on the seat so you can get in without it tipping.

I wouldn’t order any parts until you trouble shoot it.

[mooniac15u]

1 hour ago, A64Pilot said:

I’m going to have to get a look at these too I guess, from what I can tell in the logbook other than greasing and changing donuts once, there has never been anything done to the gear.

How much weight is needed to hold the tail down? I’m thinking washtub on wheels full of concrete, or is there a better way?

FWIW, Mooney advises against this.

https://www.mooney.com/wp-content/uploads/2020/12/SIM20-114.pdf

I am not advocating for following or not following this guidance.  I just thought you might want to be aware of this service instruction from Mooney.  Someone will be along shortly to tell you why you should ignore this guidance from Mooney.

[Hank]

Yep, Mooney says to lift the nose using the engine lifting eyes, because the tail isn't designed to take the weight.

Lycoming says to not lift the entire nose by the engine hoist locations, they aren't made to support the weight.

McCauley and Hartzell say to not lift or support the nose using a propeller jack, the prop isn't designed to take that much weight. 

So practice your levitation! 

My Mooney nose is supported most often by a washtub of cement but occasionally by weights on the stabilizer. You do it your way. There appears to be no "correct" way to do this, although the long bodies at some time received a nose jack point in the lower cowl area.

[N201MKTurbo]

I put an anchor in the hangar floor in 93 when I first got the hangar. I have been using it to jack the plane(s) ever since. I frequently inspect for any signs of stress or damage caused by this method. So far nothing. I will keep you informed.

[KB4]

8 hours ago, A64Pilot said:

How much weight is needed to hold the tail down? I’m thinking washtub on wheels full of concrete, or is there a better way?

Seems you have familiarity with the SM, in there they do NOT recommended to use tail, rather lifting straps attached to motor mounts and a shop crane and jacks. 

[A64Pilot]

22 minutes ago, KB4 said:

Seems you have familiarity with the SM, in there they do NOT recommended to use tail, rather lifting straps attached to motor mounts and a shop crane and jacks. 

I know,

 But I also know what Hank says is also true, Damned if  you do and Damned if you don’t. 

‘It’s not actually a lifting strap to the motor mount is it? I believe I saw either the engine lifting link,  or the prop.

[EricJ]

1 minute ago, A64Pilot said:

I know,

 But I also know what Hank says is also true, Damned if  you do and Damned if you don’t. 

‘It’s not actually a lifting strap to the motor mount is it? I believe I saw either the engine lifting link,  or the prop.

The SMMs say to use a prop stand, the prop manufacturers say to not do that.   The engine manufacturers have been cited recommending against using the lifting eye on the engine (which makes sense on Lycomings, as it's only a single 1/4" bolt holding that onto cast aluminum).   The SMM recommends against using the tail to pull the nose up (but mine then talks about precautions regarding using a tail stand, so...).   The only thing left is to use straps carefully located on the engine mount, which some very reputable MSCs have been doing for a long time.

But lots of people still use something to pull the tail down, which is what my IA does, too.   My hangar neighbor has an M20A that he's owned forever and has an anchor in the hangar floor like Rich does, and as many people as have been doing that for as long as they've been doing it I think there'd be some history of something failing as a result if it were really a problem.   Likewise I've not heard of any engine mount issues from people doing it that way, either, it's just a bit more hassle, especially if you don't have an engine hoist handy.

 

[KB4]

In a pinch to change a tire away from home I could see it being necessary and probably not likely to cause structural damages.  Manufacturer saw damage I’m assuming continued and repeatedly using tail, but just guessing about frequency.  Im guessing your J may be up in the air for few hours while you’re sorting thing out. Many use tail and many have no issues, until they do.  If Jack’s don’t have collars you can draw a sharpie line around the ram to quickly see if the jack is holding pressure while you finish up under the belly.  Harbor freight has 2 ton crane cheap. 

[RobertGary1]

11 minutes ago, KB4 said:

In a pinch to change a tire away from home I could see it being necessary and probably not likely to cause structural damages.  Manufacturer saw damage I’m assuming continued and repeatedly using tail, but just guessing about frequency.  Im guessing your J may be up in the air for few hours while you’re sorting thing out. Many use tail and many have no issues, until they do.  If Jack’s don’t have collars you can draw a sharpie line around the ram to quickly see if the jack is holding pressure while you finish up under the belly.  Harbor freight has 2 ton crane cheap. 

Unless your changing the nose tire you won't worry about it. Just raise the wing with the bad tire. 

 

-Robert

[A64Pilot]

Engine mount is strong, I used to lift my Maule with its  IO-540 by the engine mount with straps to put my 29 tires on (that’s lifting the whole airplane).

‘I’ve seen a Lycoming broken trying to lift an airplane with a collapsed nose gear to get it off of the runway, pulled a chunk out of the case

[carusoam]

Engines make expensive lifting devices...

Looks like the part count says two relays...

-a-

[A64Pilot]

7 hours ago, carusoam said:

 

Looks like the part count says two relays...

-a-

I’m thinking unless expensive to just replace the thing, it ought not be too expensive as if it’s what I think it is, they are pretty common.

it ought to be one for up and the other for down, if they are real expensive I guess I can swap them to verify the fault

Edited April 6, 2021 by A64Pilot

[PT20J]

FWIW Don Maxwell uses a couple of alternator belts, one over each blade of a two bladed prop up near the hub and lifts both belts with an engine hoist.

Most mechanics I know use the tail tiedown. If you are worried about it, throw a couple of bags of fertilizer in each side of the stabilizer near the fuselage.

Skip

[PT20J]

I’m sure everyone does this, but just in case.... don’t forget to remove your wing tie down rings before flight per SIM20-114. 

[carusoam]

14 hours ago, A64Pilot said:

I’m thinking unless expensive to just replace the thing, it ought not be too expensive as if it’s what I think it is, they are pretty common.

it ought to be one for up and the other for down, if they are real expensive I guess I can swap them to verify the fault

See if you can find the part number on them...

Master and starter relays are expensive for some unknown reason...

Some relays were cleanable and OHable back in the day...

Good luck, they might be ordinary electrical parts found on something simple...

Best regards,

-a-

[N201MKTurbo]

1 minute ago, PT20J said:

I’m sure everyone does this, but just in case.... don’t forget to remove your wing tie down rings before flight per SIM20-114. 

Yea, I’ll do that one of these days. I think I’m doing my part to just point them into the wind.