Pitch Trim DA400 GFC700
Moderators: Rick, Lance Murray
- Leesommer
- 3 Diamonds Member
- Posts: 58
- Joined: Sat Feb 03, 2018 12:47 am
- First Name: Lee
- Aircraft Type: DA40
- Aircraft Registration: N899ds
- Airports: Kcgs
- Has thanked: 10 times
- Been thanked: 17 times
Re: Pitch Trim DA400 GFC700
Well did A short flight over to Tipton and everything seemed to work pretty well after cleaning.. so we'll have to see if we have luck on a long flight
- Leesommer
- 3 Diamonds Member
- Posts: 58
- Joined: Sat Feb 03, 2018 12:47 am
- First Name: Lee
- Aircraft Type: DA40
- Aircraft Registration: N899ds
- Airports: Kcgs
- Has thanked: 10 times
- Been thanked: 17 times
Re: Pitch Trim DA40 GFC700
Well it acting up again... Tried cleaning the block, contact clearer on the trim switch on the stick. But now it won't even move the trim wheel during preflight. Sometimes if I shut off the master, turn it back on, wait for the PFT flag to go away on the PFD it will work.. Really a pain. When you have autopilot on it won't hold altitude or if it does it starts seeking up and down... I'm now thinking the switch might be dicey or could it be the pitch trim servo?
- dmloftus
- 4 Diamonds Member
- Posts: 465
- Joined: Thu May 07, 2020 3:38 pm
- First Name: David
- Aircraft Type: DA40
- Aircraft Registration: N868US
- Airports: KLZU
- Has thanked: 215 times
- Been thanked: 256 times
Re: Pitch Trim DA40 GFC700
I'm having a similar issue. My trim switch actuates the trim consistently in the nose down direction, but is intermittent or nonfunctional in the nose up direction. The trim wheel moves back and forth relatively easy by hand and the GFC700 autopilot works fine, easily moving the trim wheel back and forth so I'm thinking it's a switch contact issue. I tried to pop the trim switch out of the pilot center stick to see if there were any open contacts that I could spray with contact cleaner. Once I removed the two retaining screws, I tried to lightly pry the switch housing out of the center stick handle. But the wiring harness connected to the backside was very tight so I couldn't pull the switch out more than about 1/4" clear of the handle. I don't want to yank on it too hard for fear of damaging the wiring. Anyone removed this before and know how to relieve the tension on that wiring?
With the amount I can see, there are a couple of microswitches that look like they are sealed in plastic casings, so doubtful spraying contact cleaner at them will do much. Ideas?
This issue also got me thinking - which breaker would you pull in case of runaway trim? I don't see a breaker specifically for the trim, so I'm guessing AFCS?
- Don
- 4 Diamonds Member
- Posts: 377
- Joined: Tue Jul 06, 2010 9:15 pm
- First Name: Don
- Aircraft Type: DA40
- Aircraft Registration: N623DS
- Airports: KTOA
- Has thanked: 123 times
- Been thanked: 162 times
Re: Pitch Trim DA400 GFC700
If you don't already have one, you might want to get a breaker ring and attach it the AP breaker so you find it fast. My plane was delivered from the DAC factory with a white ring already attached.
Diamond Star XLS, N623DS, SN40.1076
- Leesommer
- 3 Diamonds Member
- Posts: 58
- Joined: Sat Feb 03, 2018 12:47 am
- First Name: Lee
- Aircraft Type: DA40
- Aircraft Registration: N899ds
- Airports: Kcgs
- Has thanked: 10 times
- Been thanked: 17 times
Re: Pitch Trim DA400 GFC700
My diamond is in for annual now. They're going to check the bridal cables and a few other things. But if that doesn't resolve as an answer then I'm taking it to a Garmin shop.
- Rich
- 5 Diamonds Member
- Posts: 4607
- Joined: Mon Aug 30, 2010 12:40 pm
- First Name: Rich
- Aircraft Type: DA40
- Aircraft Registration: N40XE
- Airports: S39 Prineville OR
- Has thanked: 145 times
- Been thanked: 1186 times
Re: Pitch Trim DA400 GFC700
The pitch trim servo does not use a cable bridle, but rather a drive-shaft and chain linkage to the trim wheel. Years ago I corrected a problem where the bolt (noted by the arrow in the picture) that connects the upper U-joint to the sprocket shaft was intermittently hanging up on a piece of excess upholstery leather underneath the copilot seat. It was tricky to identify the problem, which was uncovered by some wear in the fold of the leather. This caused behavior similar to what's being described. I trimmed that excess away and that got rid of the problem. I assume the GFC 700 PT servo uses the same linkage.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
- Leesommer
- 3 Diamonds Member
- Posts: 58
- Joined: Sat Feb 03, 2018 12:47 am
- First Name: Lee
- Aircraft Type: DA40
- Aircraft Registration: N899ds
- Airports: Kcgs
- Has thanked: 10 times
- Been thanked: 17 times
Re: Pitch Trim DA400 GFC700
Thanks Rich I will definitely have them take a look at that once they're working under the seat
- Leesommer
- 3 Diamonds Member
- Posts: 58
- Joined: Sat Feb 03, 2018 12:47 am
- First Name: Lee
- Aircraft Type: DA40
- Aircraft Registration: N899ds
- Airports: Kcgs
- Has thanked: 10 times
- Been thanked: 17 times
Re: Pitch Trim DA400 GFC700
Well, to close the story hopefully. Went to Delta Fox at HEF and replaced the trim pitch servo... Let's hope this solves the problem. 2hrs after and no issue.
- Leesommer
- 3 Diamonds Member
- Posts: 58
- Joined: Sat Feb 03, 2018 12:47 am
- First Name: Lee
- Aircraft Type: DA40
- Aircraft Registration: N899ds
- Airports: Kcgs
- Has thanked: 10 times
- Been thanked: 17 times
Re: Pitch Trim DA400 GFC700
Sorry for such a later follow-on reply... the replacment servo did the job.... No issues even a year later.
Lee
Lee