New SB (SB-G09) on elevator pushrods for most all Grobs

I checked our Twin Astir. No water or rust flakes came out of the drilled hole. Just to be sure I found a 5.5mm diameter wifi borescope on Amazon and had a look inside. Looked clean to me.

On Sunday, May 10, 2020 at 3:40:32 PM UTC-6, wrote:
On Sunday, May 10, 2020 at 2:55:29 PM UTC-4, okko kloosterman wrote:
Could you give some information on the required tool modifications?
Thanks.
OK


9-5-2020 19:52 wrote:
On Tuesday, May 5, 2020 at 10:17:09 AM UTC-4, soaringjac wrote:
See the link below

http://www.ltb-lindner.com/g-102-ad-...rod_200408.pdf

Our Grob 102 Astir CS had the "welded version" elevator pushrod consistent with the Service Bulletin.

BTW: All the hardware requires 10 mm wrenches. The elevator pushrod bolt & nut required a modified box wrenches.

Chuck Zabinski


The 10 mm box wrenches were ground down to thin the outer circular support structure that supports the gripping teeth. This lets the wrench fit into bolt access recess in the rudder. Even with that, a slight amount of Dremel work may be required to get the wrench to fit on the bolt nut. Also small hands and patience are required to remove the elevator pushrod bolt.

Chuck Zabinski

Chuck, can you take a photo of the 10mm wrench after modification? Our club has 5 G-103, four of which are affected by this SB. We are looking at the inspection, but it sounds like your tool mod would be good prep work. Can you post or send me a photo of the tool after modification?

David

I've just done our Astir CS.

A few tips:

Lifting the tail onto a tressle for better access made it a lot easier. You will also need to adjust the trim to get the bell crank in a suitable position for disassembly. If i remember right, about 3/4 stick back was about right.

To get the lower rudder bolt off, a standard 10mm open end spanner fits on vertically (not side on as normal) and wedged into the small gap between the rudder and fin. Allen key in the bolt on top. I was a bit worried about the spanner damaging the rudder , but the release torque on the bolt was pretty low so no trouble here.

Access to the nut/bolt at the bottom of the pushrod is tricky, but possible (I have big hands so at a bit of a disadvantage here!) You'll need 2x 10mm spanners, one with a ratchet. Ours was installed with the bolt through from the left (close to the fin skin) and the nut on the right, open side. I would recommend keeping it this way as getting the nut on the skin side would be tricky to say the least.
Open end spanner on the bolt head, ideally with a bit of tape on the back side to prevent it from falling off. Ratchet spanner on the nut. The open end spanner will need bracing on the bottom of the fin (left hand) and the nut loosened with the right hand. Light pressure on the ratchet spanner is needed to stop it falling off the nut, which means you have to put your hand quite far in, restricting the ratchet motion to 1 or 2 clicks. Not a quick job in other words! Be careful when taking the nut off as it can fall into the tail boom through the bulkhead holes and is a bugger to get back out (don't ask!)

Drilling the hole is straight forward, although not sure how they expect you to deburr the inside of the hole!?

I took the chance to restore the paint on the rod, as I didn't fancy ever having to take it out again!

Reassembly posed its own challenges, especially as a 1 man job. Ideally you will have someone to hold the rod in position from above while you reassemble the joint, but if not you can rest the pushrod on the bellcrank with the correct trim position. 2 problems:
1. The bolt was too long to fit back in between the rod and the fin skin
2. I couldnt get both hands in to push the bolt in while holding the rod in the correct position
I used the other bolt off the rudder/pushrod connection, and partially inserted the win the wrong (right!) side of the joint to align it, then inserted the actual bolt in the correct way, coming in from above at downward angle to fit in the tight gap. Then remove the rudder bolt and push the main bolt in all the way. Similar setup with taped spanner & ratchet spanner to re-assemble and same strategy for the rudder hinge bolt

No corrosion in ours either, and that is with a very leaky trailer!

The club Twin II Acro has been another story altogether, seems that the wrong pushrod (rivetted version) was installed and impossible to remove through conventional means, so a few new holes going in that one by the looks of it

At 14:17 05 May 2020, soaringjac wrote:
See the link below

http://www.ltb-lindner.com/g-102-ad-sb.html?
file=tl_files/ltb_lindner/pdf/G%20102%20LTA%20%26%20TM%2
0Englisch/SB-G09_elevator%20pushrod_200408.pdf



So did anybody find any evidence of corrosion in the pushrods ?

At 14:17 05 May 2020, soaringjac wrote:
See the link below

http://www.ltb-lindner.com/g-102-ad-sb.html?
file=tl_files/ltb_lindner/pdf/G%20102%20LTA%20%26%20TM%2
0Englisch/SB-G09_elevator%20pushrod_200408.pdf



So did anybody find any evidence of corrosion in the pushrods ?

AD published by EASA:

https://ad.easa.europa.eu/ad/2020-0121

On Thursday, May 28, 2020 at 4:30:05 AM UTC-5, Eric Munk wrote:
AD published by EASA:

https://ad.easa.europa.eu/ad/2020-0121

Interesting, The original lindner documents exclude aluminum control rods, the EASA documents only has "steel" but is not as clear as Lindners exclusion.
Scott

On Thursday, May 28, 2020 at 8:51:05 PM UTC-5, Scott Williams wrote:
On Thursday, May 28, 2020 at 4:30:05 AM UTC-5, Eric Munk wrote:
AD published by EASA:

https://ad.easa.europa.eu/ad/2020-0121

Interesting, The original lindner documents exclude aluminum control rods, the EASA documents only has "steel" but is not as clear as Lindners exclusion.
Scott

That is the 103 twin II at least,

On Thursday, May 28, 2020 at 9:51:05 PM UTC-4, Scott Williams wrote:
On Thursday, May 28, 2020 at 4:30:05 AM UTC-5, Eric Munk wrote:
AD published by EASA:

https://ad.easa.europa.eu/ad/2020-0121

Interesting, The original lindner documents exclude aluminum control rods, the EASA documents only has "steel" but is not as clear as Lindners exclusion.
Scott

Best to look at the serial number of your Grob. For the G103 there is a serial number range, that is excluded. The TN issued by Lindner spells out which serial numbers are affected or excluded.

Uli
'AS'

Well it’s not a FAA AD yet. Anyone know if there’s a NPRM for it yet?