Grob gliders, new TM about control system pulleys

[Robert M]

5 Feb. 2014

A Tech Note for Grob gliders has recently been issued by the Type Certificate holder, Fiberglas_Technik, Rudolf Lindner of Germany.

TM-G05 Calls for the replacement of the 42mm diameter white or brown plastic pulleys with aluminum ones. The plastic ones crack. This applies to several versions of the G-102 and G-103 gliders.

The pulleys are found on rudder pedals and front mounted tow hooks. Over the last 10 years or so I have replaced several sets of these pulleys. About 75% of the ones I look at are cracked.

The EASA has issued an AD note for this, (AD 14-027). It is highly likely that the FAA will issue an AD note. This concerns a control system and the plastic pulleys have broken. There is no doubt in my mind an FAA AD will be issued.

There are two time lines for replacement depending on how the pulleys are mounted.

I strongly urge US, Canada and Mexico based Grob owners to read and understand the TM. It is available at http://ltb-lindner.com/g-103-ad-sb.html .

I'll be ordering some pulleys but it would be good to know how many owners will need them.

Robert Mudd
Composite Aircraft Repair LLC
Moriarty, New Mexico
Come for the thermals, stay for the sunsets

[Dan Daly[_2_]]

Thanks, Robert, I cross-posted this to the Soaring Association of Canada "Flight Safety Flash" section (Google translated to French too) with your contact info.

[WB]

On Wednesday, February 5, 2014 2:14:48 PM UTC-6, Robert M wrote:
> 5 Feb. 2014
>
>
>
> A Tech Note for Grob gliders has recently been issued by the Type Certificate holder, Fiberglas_Technik, Rudolf Lindner of Germany.
>
>
>
> TM-G05 Calls for the replacement of the 42mm diameter white or brown plastic pulleys with aluminum ones. The plastic ones crack. This applies to several versions of the G-102 and G-103 gliders.
>
>
>
> The pulleys are found on rudder pedals and front mounted tow hooks. Over the last 10 years or so I have replaced several sets of these pulleys. About 75% of the ones I look at are cracked.
>
>
>
> The EASA has issued an AD note for this, (AD 14-027). It is highly likely that the FAA will issue an AD note. This concerns a control system and the plastic pulleys have broken. There is no doubt in my mind an FAA AD will be issued.
>
>
>
> There are two time lines for replacement depending on how the pulleys are mounted.
>
>
>
> I strongly urge US, Canada and Mexico based Grob owners to read and understand the TM. It is available at http://ltb-lindner.com/g-103-ad-sb.html .
>
>
>
> I'll be ordering some pulleys but it would be good to know how many owners will need them.
>
>
>
> Robert Mudd
>
> Composite Aircraft Repair LLC
>
> Moriarty, New Mexico
>
> Come for the thermals, stay for the sunsets

Had a front seat rudder cable pulley on a Grob start coming apart while giving a ride once. Took considerable force to move the rudder and had somewhat limited rudder movement. Made a short flight of it.

[[email protected]]

Thanks for pointing this out! I've ordered replacement pulleys which we can install during the annuals before the season starts.

[CLewis95]

ALSO CHECK THE TOW RELEASE PULLEYS! .. we had a cracked one.

[Robert M]

On Friday, February 14, 2014 7:58:12 AM UTC-7, CLewis95 wrote:
> ALSO CHECK THE TOW RELEASE PULLEYS! .. we had a cracked one.

What I and other repair shops have found over the years is that all of the non metal pulleys, both white or brown will crack. They may not be cracked now but they will crack. The TM calls for the pulleys on the rudder pedals and the front tow hook to be replaced with metal ones.

Some early Twin IIs do not have pulleys on the rudder pedals but do have a plastic pulley on the forward tow release. It can not be seen without removing a fiberglas cover at the front bulkhead. The bolts in the cover also attach the tow hook so it may be a good time to install a new tow hook. The cover is so diffacult to get to that the tow hook in there likely has never been replaced.

There is also can be a plastic pulley inside the center of the front instrument panel. It is part of the tow release cable system for gliders with both the front and C.G. hooks installed. While not required to be replaced by the TM it too should be replaced. Also in the G-102 Std III there is a plastic pulley just in front of the center of gravity hook under the seat pan. It too should be replaced. So the bottom line is replace all the white and brown pulleys with new metal ones. You have to dig a little to find them all.

The cost of replacing the plastic pulleys is far less than the cost of repairing damage that could be done by having a cable jam when the plastic brakes.

Each pulley I sell will also come with a new fiberlock nut for the axle bolt.

Robert Mudd