Solved: Are my main gear hitting the wing on retract?

[anthonydesmet]

36 minutes ago, Aerospace said:

Maybe I do, seems logical. Except doesn't that switch, in addition to activating the alarm, also disable the gear from retracting? I'll do the gear swing soon and will know either way, just got back from the affordable airplane jack store (HF). Yours is a '77 right?

Thanks, your '89 may be the same as my '92

 

Thanks.

Can I ask what your airspeed was and MP/throttle was during the time the alarm was going off?  WOT/105+. Just curious.

[Ragsf15e]

Again, I’m only an internet mechanic, but if the gear actually went up and down as you put the switch up and down, it’s not the airspeed switch.  That failing causes the gear not to come up at all.  Also, it’s very unlikely that the gear actually hit the airframe, and that would very likely cause a popped gear actuator circuit breaker.

So you’re looking at the throttle switch or the limit switches.  @PT20J probably has the electrical diagram memorized, but can the limit switches trigger the gear alarm or is it only triggered by the throttle switch?

You see, I had this same failure happen (admittedly on a much older F model), and it was fixed with some lps 1 and exercising the throttle switch…

Edited August 3, 2023 by Ragsf15e

[Aerospace]

1 hour ago, anthonydesmet said:

Can I ask what your airspeed was and MP/throttle was during the time the alarm was going off?  WOT/105+. Just curious.

WOT/80, then the second try was about 24 inhg and 100

[Aerospace]

35 minutes ago, Ragsf15e said:

Again, I’m only an internet mechanic, but if the gear actually went up and down as you put the switch up and down, it’s not the airspeed switch.  That failing causes the gear not to come up at all.  Also, it’s very unlikely that the gear actually hit the airframe, and that would very likely cause a popped gear actuator circuit breaker.

So you’re looking at the throttle switch or the limit switches.  @PT20J probably has the electrical diagram memorized, but can the limit switches trigger the gear alarm or is it only triggered by the throttle switch?

You see, I had this same failure happen (admittedly on a much older F model), and it was fixed with some lps 1 and exercising the throttle switch…

Yeah, that's what I was thinking about it not being the airspeed switch. I will check the throttle and limit switches though, that really seems to make sense, thanks.

[PT20J]

5 hours ago, Aerospace said:

What does the gear indicator show when the gear is fully up? When I commanded the gear retract, the alarm sounded instantly and the gear unsafe annunciator lit up. I gave it plenty of time to retract, like 20 seconds, and the annunciator, alarm, and barber pole never went away. So I put the switch down and for the life of me it felt like a normal gear extension with the change in drag and speed and attitude and the reassuring soft clunk.

There are some clues here. If the airspeed switch is defective, you will get the warning horn immediately upon placing the gear switch in the up position, the adjacent red override button will illuminate and the gear will not move as evidenced by the floor indicator showing green alignment makes matching up. Since you indicate that you had the barber pole showing on the floor indicator and when you subsequently lowered the gear you got various indications of a normal extension, it seems that the gear did in fact retract. Therefore it is not the airspeed switch.

The fact that you got an immediate warning when the gear switch was put in the up position points to a throttle switch. You said you also had a steady gear unsafe light on the annunciator which might also implicate the gear up limit switch. 

The problem will be apparent when you can jack the plane and investigate.

[A64Pilot]

If you want to come down to 97FL we can swing the gear, it’s grass but I have no issues and I have lower gear doors, they do add a couple of kts.

I have a hangar that’s sort of airconditioned, sort of as it can’t keep it house cool, but it can hold 80ish and 50 something humidity when it’s 90 and 90 outside.

https://www.airnav.com/airport/97FL

Edited August 3, 2023 by A64Pilot

[Aerospace]

7 hours ago, A64Pilot said:

...come down to 97FL we can swing the gear, it’s grass but I have no issues and I have lower gear doors, they do add a couple of kts.

Thanks for the offer, that's very kind. I just may do that depending on weather over these next few days.

[Aerospace]

I took @A64Pilot up on his offer and flew to his place to check it out.

Bottom line is that it was the low throttle switch just like @Ragsf15e said.

That was my first grass runway operation, very cool, fun rolling slopes, very smooth, 10/10 reccomend.

Thanks @A64Pilot!

[Aerospace]

On 8/2/2023 at 8:25 PM, toto said:

Yes.  On my J, a red and white barber pole means "up" and a green "Gear Down" indicator means down.

Confirmed, rolling barber pole during transit, static barber pole when up.

[M20F]

On 8/2/2023 at 5:33 PM, Ragsf15e said:

My terribly uneducated guess… throttle gear warning switch.  Free on the internet.

Now that I see this is the correct answer I am going to go with this as well.  

[Ragsf15e]

2 hours ago, M20F said:

Now that I see this is the correct answer I am going to go with this as well.  

Better lucky than good!