jcovington

Daytona Gear Incident

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On 4/27/2018 at 4:47 PM, jcovington said:

On April 26th my wife and I were traveling to Nassau for a long weekend in the Bahamas. We planned a stop in Daytona Beach for fuel. When we departed Huntsville, AL there was a low pressure to the west pushing a cold front to the east so we had to pass through about 90 miles of light to moderate rain. When we arrived at Daytona Beach the controler took us several miles off shore to enter a right base for 25R. To make sure we had our best glide in case of an engine problem I left the gear up until we started our descent on final. 

As we started to descend on final I put the gear switch down and started my gear checks. Switch down, manual gear indicator in the floor in the green and and gear down light on is my normal procedure. When I looked at the floor indicator I remarked to my wife that the light must have burned out as it was hard to see the green indicator but it was there and I could see it. When I looked at the annunicator gear light it was off. At this point I knew something was wrong but I didn't know what. I am still at a couple thousand feet so I had time to cycle the gear up and back down and had the same indications. I checked the manual gear cover to be sure it was latched and I pulled the manual gear handle to confirm the gear was down. It is now time for a different plan as I knew I wasn't landing without a gear light since I didn't trust that the gear was locked down even though I was confident the gear was down. I thought I probably had a stuck or broken gear down switch.

I have always felt and I teach my complex students that the worse place to diagnose a problem is in the pattern. Close to the ground is no place to deal with the distractions of a gear problem. My call to tower was "Daytona tower, Mooney 49Q has a gear problem and needs to depart the pattern to troubleshoot the issue". He immediately offered an orbit over the speedway and a climb to 1500 feet which I took. In hindsight, maybe not the best spot since I had to stay away from the runways which was a lot more complicated because the autopilot was randomly disconnecting. Lots of distractions during the entire event including the tower asking fuel and souls on board. The tower was great during the entire event but I did have to ask him to standby once since I was feeling overloaded. Flying, troubleshooting and talking was one too many things to do. Things got really quiet after that.

After arriving at the speedway and getting the altitude back where it belonged I started troubleshooting the gear issue. At this point I planned to manually put the gear down since I had tried all the electric troubleshooting I could. When I reached to the circuit breaker panel to pull the electric gear breaker I noticed the gear indicator breaker was popped which explained the lack of lights. I pressed the gear indicator breaker back in and put the gear down which promptly tripped the breaker again. Not good. Next plan is to pull the breaker and manually extend the gear. That worked but I still didn't have a gear light. I reset the gear light breaker and the lights came on. I told the tower that I had a gear down indication and I was ready to land. He sent me on a fairly long downwind since he had two jets to land. I didn't realize until later but the controllers were holding the other planes on the ground to give us the runway.

During the downwind leg I heard someone asking about the alert aircraft and realized they were talking about us. That was a bit sobering. When we turned final we had two fire trucks and an ambulance on our left. They had four trucks at various places on the right of the runway. Lots of airplanes holding on the parallel taxiway since Emery Riddle does a lot of training here. Ok, this is for real. I made a nice slow descent and as gentle touchdown as I could. The gear stayed locked down and after I made the right turnoff on the taxiway I felt fairly confident that the gear wasn't going to collopse. We had one of the alert trucks and a fire truck follow us for a while. The alert truck followed us to the ramp and the airport authority guy took our statement. End of the incident but I still have a broken airplane and reservations in Nassau.

First step is to call Joey Cole and get some advice. He is at lunch and will have to call me back. Daytona Aircraft Services is on the field and were kind enough to put the plane on jacks to check the gear. We performed several gear cycles and no issues were seen. We pulled the gear indicator and confirmed that the gear would lock down even if the gear down indicators wouldn't light. The guys at Daytona Aircraft Services were confident that there were no issues with the gear and that I just had a problem with the gear indicator system. 

When I spoke with Joey and told him the problem his first question was did I fly through a lot of rain. I said that I had flown through about 45 minutes of moderate rain that morning. Joey said that water can cause issues with the gear indicators and that was probably what happened.

At this point I felt comfortable that the gear would come down even if the indicators failed to work. We fueled and loaded up to depart for Nassau. When we arrived in Nassau the gear extended and the lights lit with no issues. When we get home I plan to pull the wiring diagram and check for anything that could cause the breaker to trip.

What I did right:
    1) Left the pattern to diagnose the problem
    2) Managed the flight and got all the help I needed
    3) Didn't do anything to make it worse. I was really tempted to cycle the gear instead of getting it on jacks. How much worse would it have been if I had the gear down, put it up and then it wouldn't come down. 
    4) Landed at a field that had a Mooney service center on the field.

What I did wrong:
    1) I should have gotten out the checklist instead of doing everything by memory. I would have caught the popped breaker sooner.
    2) I should have cancelled my IFR clearance sooner. I didn't need it and it made the controller's and my job harder. I definitely busted my assigned altitude due to distraction.

I didn't declare an emergency but I am sure the tower controller did it for me. It will be interesting to see if I hear anything from the FAA about the event.
 

Interestingly enough ... I had this similar situation in a Piper Arrow (PA-28) in the early 1990s when we put the gear down before landing in Tallahassee (KTLH). No lights. Three dark un-illuminated gear lights. It was a rental; the FBO Owner was in the right seat and had just finished “checking me out” in the plane so I could rent it. (I remember being disappointed and thinking to myself, “I guess the checkout isn’t over yet”) We aborted the approach, talked to tower and exited the pattern. The gear was down, we thought, we felt it come down, but there were no green lights ... all three lights were out. Hmmm ... We performed the emergency extension procedures, returned for a a low approach, asked tower what they saw? Tower said, “They looked down,” to which we asked “all three?” He said ... “ all three look down, from what I can see, but I can’t guarantee anything.” We went back around the pattern and landed. Uneventfully.

After touchdown, I remember holding back pressure and keeping the nose wheel up until there wasn’t enough wind over the elevators to hold it up. We had discussed this prior ... just in case the nosewheel wasn’t locked. We discussed it ... but I can’t remember if we decided to pull the mixture and cutoff the engine at that point or not? But we had discussed that as well ...

My confusion “Oh ... Hello!” moment during the flight came (after we had aborted the approach and I discussed an emergency gear extension) when I looked at the owner and said ... “ok ... you can push the circuit breaker back in.” He looked at me and said ... “I didn’t pull any circuit breakers ... “ 

The conclusion,  more or less, was that the gear was functioning, was down and locked, but the indicator lights were all inoperative. An avionics shop had just completed some radio work, during which they had  (improperly) re-routed the gear light wires in such a way that we think they were caught and pulled loose when we moved the flight controls during the pre takeoff checks. To this day, I’m thinking the lights were already off when we took-off ... and we just didn’t notice? We’ll never know for sure ...

Edited by David Herman
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7 hours ago, David Herman said:

Interestingly enough ... I had this similar situation in a Piper Arrow (PA-28) in the early 1990s when we put the gear down before landing in Tallahassee (KTLH). No lights. Three dark un-illuminated gear lights. It was a rental and the FBO Owner had just finished “checking me out” in the plane so I could rent it. (I remember being disappointed and thinking to myself, “I guess the checkout isn’t over yet”) We aborted the approach, talked to tower and exited the pattern. The gear was down, we thought, we felt it come down, but there were no green lights ... all three lights were out. Hmmm ... We performed the emergency extension procedures, returned for a a low approach, asked tower what they saw? Tower said, “They looked down,” to which we asked “all three?” He said ... “ all three look down, from what I can see, but I can’t guarantee anything.” We went back around the pattern and landed. Uneventfully.

After touchdown, I remember holding back pressure and keeping the nose wheel up until there wasn’t enough wind over the elevators to hold it up. We had discussed this prior ... just in case the nosewheel wasn’t locked. We discussed it ... but I can’t remember if we decided to pull the mixture and cutoff the engine at that point or not? But we had discussed that as well ...

My confusion “Oh ... Hello!” moment during the flight came (after we had aborted the approach and I discussed an emergency gear extension) when I looked at the owner and said ... “ok ... you can push the circuit breaker back in.” He looked at me and said ... “I didn’t pull any circuit breakers ... “ 

The conclusion,  more or less, was that the gear was functioning, was down and locked, but the indicator lights were all inoperative. An avionics shop had just completed some radio work, during which they had  (improperly) re-routed the gear light wires in such a way that we think they were caught and pulled loose when we moved the flight controls during the pre takeoff checks. To this day, I’m thinking the lights were already off when we took-off ... and we just didn’t notice? We’ll never know for sure ...

I had a similar thing in an Arrow I used to rent, but it turned out it was just that whoever flew it previously flew it at night and had turned the lights down.   I'd done a go-around to sort it out and figured it out on downwind, but it was definitely one of those "hmmmm...let's sort this out..." moments.

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Interesting comments on the number of gear indicator failures that people have had (in Arrows and Mooneys). It is a failure that I have never practiced or discussed. I do plan to present the gear indicator failure as a scenario in future flight reviews that I conduct. Hopefully, it will make it less confusing if someone sees it in the future.

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My wife and I returned from Nassau on Monday with a stop in Ft. Pierce to clear customs. The gear and gear warning system worked for all takeoffs and landings without issues. I do find myself looking at the breakers while the gear is transitioning to be sure nothing has tripped. It will be interesting to see if I retain that as a habit.

I have started to review the gear warning schematic and compared it to Vance’s excellent write-up in this thread. There are a few differences between the J model that I have and Vance’s F model. I have an annunciator panel instead of up/down lights but the signal going to the annunciator panel is the same. The Gear Warning breaker also powers a tone generator that is mounted on the inside firewall.

The J model doesn’t have access panels in front of the windshield as the F does so water is less likely to get to the back of the panel. It is still a possibility since there are screws, wires, etc. that do penetrate. I plan to check that carefully to make sure I don’t have a leak that needs to be plugged. I also plan to check the Gear Down Light and the Gear Down Limit switch that are under the floor. We had flown through a lot of rain that morning so I wouldn’t be surprised that I had water under the belly pan. I also plan to look for loose/broken/chaffed wires behind the panel and under the belly pan.

I have attached a drawing that I made of the gear connections. I have highlighted in yellow the circuit that the Gear Warn breaker powers when the gear is in the down position (the point that the breaker tripped). These are the components that I will start with.

I’ll report back with the results of my checks. It might be a few weeks as I have some commitments coming up.

Landing Gear Gear Warn Markup.pdf

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33 minutes ago, jcovington said:

I do find myself looking at the breakers while the gear is transitioning to be sure nothing has tripped. It will be interesting to see if I retain that as a habit.

Sounds like a good habit.  I'm going to steal that.

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Nice highlight technique JC!

Thanks for sharing that drawing.

best regards,

-a-

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Update: This past Saturday I had some time and decided I would spend the time in the hangar looking for the cause of the gear warning breaker trip. Looking over the gear schematic I decided to concentrate on the gear down limit switch, gear/stall warning audio tone generator and the throttle switch. At the last annual, the throttle cable had to be replaced due to it slipping. Knowing that the throttle switch is mounted on the cable I decided to check there first.

The throttle switch is a fairly inexpensive micro-switch with none of the contacts sealed. Since they aren’t sealed there is some play in the switch terminals. Next to the throttle switch, on either side, are two mounting screws that let you adjust where the switch will trip to set off the gear warning when the throttle is pulled back past a certain point. Fairly simple arrangement that works well.

I think at this point you can probably tell where this is going. When I crawled into the left foot well and looked at the throttle switch I noticed that the lower forward ring terminal was very close to the forward adjustment screw, that the cable bundle going to the throttle switch was unsecured and a rubber grommet around the throttle cable was partially out. I reached up and moved the wire bundle and the ring terminal contacted the forward adjustment screw. I looked for charred marks on the ring terminal to confirm that this caused the breaker to trip. I didn’t see any charring but it did look like some brown discoloration on the ring terminal although it was hard to tell for sure. It would have been nice to see the charring although with a one amp breaker I would have been surprised to see much.

The solution was to bend the ring terminal up away from the adjustment screw, to secure the cable bundle with a tie wrap and to reinstall the rubber grommet around the throttle cable. I know that there was enough movement in the cable/switch terminals to allow the ring terminal to contact the screw. I believe that movement of the throttle with the unsecured wire bundle was enough to have it happen in flight tripping the breaker when the gear was extended.

After finding the throttle switch issue I talked myself out of pulling the belly pan since I feel I found the issue. I will most likely pull the belly pan next time I do an oil change just for a general inspection.

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Excellent analytical work, and write-ups, Jim. I can remember when I was thin enough to get under the pilot foot well to check things out. Those days have passed.

Have a safe trip and see you and your beautiful bride in a couple of weeks. :)

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2 hours ago, fantom said:

 I can remember when I was thin enough to get under the pilot foot well to check things out.

I still can :D

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Do all electric gear Mooneys not have the sight glass in the floor between the seats? That has always seemed to me to be the fool proof indicator of gear down. If the little light burns out, I can always see it with the flashlight on my phone. 

One of the nice things about the manual gear Mooneys is that no lights, horn, or anything is required to verify gear down and locked.

I've been assuming the sight glass in the floor was basically the same thing for my K.

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Nice details, JC!

Random sparks inside the cabin would be bad...  as would be random vapors from leaky tanks...

Keep both the sparks and the vapors nicely contained.  :)

Thanks for the great follow-up!

Best regards,

-a-

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Do all electric gear Mooneys not have the sight glass in the floor between the seats? That has always seemed to me to be the fool proof indicator of gear down. If the little light burns out, I can always see it with the flashlight on my phone. 
One of the nice things about the manual gear Mooneys is that no lights, horn, or anything is required to verify gear down and locked.
I've been assuming the sight glass in the floor was basically the same thing for my K.


They do. If you pull the gear warning breaker on my plane, the gear indicator lights next to the switch and the floor indicator light won’t light. I suspect he was getting the correct mechanical indication on the floor but just couldn’t see it.

I had the light in the floor indicator stop working once. It’s really hard to see without a flashlight to illuminate it.


Sent from my iPhone using Tapatalk Pro
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33 minutes ago, gsxrpilot said:

Do all electric gear Mooneys not have the sight glass in the floor between the seats? That has always seemed to me to be the fool proof indicator of gear down. If the little light burns out, I can always see it with the flashlight on my phone. 

One of the nice things about the manual gear Mooneys is that no lights, horn, or anything is required to verify gear down and locked.

I've been assuming the sight glass in the floor was basically the same thing for my K.

I did have a manual downlock indicator in the floor. I did not have a gear down light or the light in the floor window. At the time I didn't understand the gear warning system as well as I do now. I was afraid that without the lights the gear was not locked. After Daytona Aircraft put the plane on jacks and explained the gear warning system I understood that the gear was down and locked. The only problem was the lights weren't lit.

Even with the new knowledge I have about the gear warning system I would still break off the approach to do the troubleshooting. I just wouldn't have the pucker factor now that I did then.

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Back when my gear motor breaker would trip, I would hear it go and also feel the gear not doing what they were supposed to do for the proper amount of time.     I am not sure if my transition instructor did it or I started it, but Gear Switch.  Wait a few.   Check Floor indicator.  Short short final, I check for Green light and check floor.  There are probably a couple other times I check.   A couple years ago when I videoed myself, I checked the gear 4 times.

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Another update: This past Saturday I took the plane up for a short flight since it hadn’t been flown in a couple of weeks. Coming back into the airport I put the gear down and had another gear warning breaker trip. Looks like my earlier diagnostic finding of the ring terminal rubbing on the throttle position switch was wrong or at least incomplete.

I am a lot more comfortable now that I know the gear is down even with the gear warning breaker tripped so I spent some time troubleshooting. I pushed the gear warning breaker in with the gear down and got the gear down lights with the breaker staying in. I cycled the gear up and the gear warning breaker tripped. Pushed the breaker in and cycled the gear down. The gear warning breaker tripped again. Pushed the gear warning breaker in again with gear down, got all the lights and the breaker stayed in. The problem has to be something within the gear unsafe circuit or perhaps a frayed/loose wire.

When I returned to the hangar I dropped the belly panel and looked at the wiring for the gear system. I didn’t see anything loose or frayed. That was as far as I got on Saturday.

This week I have spent quite a bit of time examining the gear wiring circuit to identify the likely points I need to check. I concentrated on the gear unsafe circuit and came up with the following items to check

1)      Connector RC09A/PL09A for loose pins/corrosion

2)      Connector RC14A/PL14A for loose pins/corrosion

3)      Connections on the up/down limit switches for loose wires/corrosion

4)      Replace D1 Diodes on RC14A/PL14A and RC09A/PL09A

5)      Look for frayed wires around the gear mechanism

6)      Test the 1 amp gear warning breaker

I have had several flights (about 10 hours total) with no issues with the gear warning breaker. When it happens it will consistently fail and then the next flight work with no issues. I think it is likely that the D1 diodes are going bad letting current flow where it shouldn’t. Since the diodes are located on the PL14A/PL09A connectors I will replace them while I look for bad pins/corrosion.

I will be playing find the connectors in the wire bundles on Friday. I’ll report back what I find.

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On 6/13/2018 at 9:41 AM, jcovington said:

Another update: This past Saturday I took the plane up for a short flight since it hadn’t been flown in a couple of weeks. Coming back into the airport I put the gear down and had another gear warning breaker trip. Looks like my earlier diagnostic finding of the ring terminal rubbing on the throttle position switch was wrong or at least incomplete.

I am a lot more comfortable now that I know the gear is down even with the gear warning breaker tripped so I spent some time troubleshooting. I pushed the gear warning breaker in with the gear down and got the gear down lights with the breaker staying in. I cycled the gear up and the gear warning breaker tripped. Pushed the breaker in and cycled the gear down. The gear warning breaker tripped again. Pushed the gear warning breaker in again with gear down, got all the lights and the breaker stayed in. The problem has to be something within the gear unsafe circuit or perhaps a frayed/loose wire.

When I returned to the hangar I dropped the belly panel and looked at the wiring for the gear system. I didn’t see anything loose or frayed. That was as far as I got on Saturday.

This week I have spent quite a bit of time examining the gear wiring circuit to identify the likely points I need to check. I concentrated on the gear unsafe circuit and came up with the following items to check

1)      Connector RC09A/PL09A for loose pins/corrosion

2)      Connector RC14A/PL14A for loose pins/corrosion

3)      Connections on the up/down limit switches for loose wires/corrosion

4)      Replace D1 Diodes on RC14A/PL14A and RC09A/PL09A

5)      Look for frayed wires around the gear mechanism

6)      Test the 1 amp gear warning breaker

I have had several flights (about 10 hours total) with no issues with the gear warning breaker. When it happens it will consistently fail and then the next flight work with no issues. I think it is likely that the D1 diodes are going bad letting current flow where it shouldn’t. Since the diodes are located on the PL14A/PL09A connectors I will replace them while I look for bad pins/corrosion.

I will be playing find the connectors in the wire bundles on Friday. I’ll report back what I find.

My similar situation was a foreign metal object that had fallen into the throttle position switch that was causing a short to ground a popping the gear light breaker ('69 F model though) 

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