AD note for G-103, Grob two seat gliders

[Robert M]

A new AD note has been issued by the FAA concerning the airbrake locking system of all models of the G-103 glider certificated in any category. This means it applies to G-103s in the EXPERIMENTAL category too.

AD 2015-22-04 becomes effective 4 December 2015. And has two different compliance times. It is available at: http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/MainFrame?OpenFrameSet

The AD references two Service Bulletins issued by the Type Certificate holder, Fiberglas Technik Rudolf Lindner GmbH in Germany. http://ltb-lindner.com/

The SBs are available at Lindner's web site.

SB-G07 Instructions for installing an inspection opening to the underside of the wings.
SB-G08 Instructions for checking the locking force of the airbrake system and adjusting it if necessary, and inspection the locking lever for cracks. It also calls for this inspection to be performed at each Annual Inspection.

Lindner is working on a permanent fix which I assume would include replacing the locking lever in question. That may take a while.

Many G-103s already have the inspection hole installed. They are a great help when doing the inspection for cracks in the locking lever and mandatory for adjusting the over center locking force. I highly recommend installing the inspection holes even if your initial inspection shows no cracks and the locking force is within limits,

If you have questions contact me at 505 269-8234

Robert Mudd
Composite Aircraft Repair
Moriarty, New Mexico.

[Bill T]

We got a heads up based on the European AD equivalent release, Knowing the FAA would follow. Our Annual inspection was due so we completed and logged the SB inspections. All was good.
Now the AD says "unless already completed" comply within 30days. We are done until our next annual. Thanks for the heads up JS.

We do not have the inspection ports in the lower wing, we were able to inspect and take pictures with a long lighted bore scope through the wing root.
Interesting comment about installing those inspection ports, are clear plastic covers available?
BillT

[[email protected]]

On Friday, October 30, 2015 at 11:06:39 AM UTC-6, Robert M wrote:
> A new AD note has been issued by the FAA concerning the airbrake locking system of all models of the G-103 glider certificated in any category. This means it applies to G-103s in the EXPERIMENTAL category too.
>
> AD 2015-22-04 becomes effective 4 December 2015. And has two different compliance times. It is available at: http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/MainFrame?OpenFrameSet
>
> The AD references two Service Bulletins issued by the Type Certificate holder, Fiberglas Technik Rudolf Lindner GmbH in Germany. http://ltb-lindner.com/
>
> The SBs are available at Lindner's web site.
>
> SB-G07 Instructions for installing an inspection opening to the underside of the wings.
> SB-G08 Instructions for checking the locking force of the airbrake system and adjusting it if necessary, and inspection the locking lever for cracks. It also calls for this inspection to be performed at each Annual Inspection.
>
> Lindner is working on a permanent fix which I assume would include replacing the locking lever in question. That may take a while.
>
> Many G-103s already have the inspection hole installed. They are a great help when doing the inspection for cracks in the locking lever and mandatory for adjusting the over center locking force. I highly recommend installing the inspection holes even if your initial inspection shows no cracks and the locking force is within limits,
>
> If you have questions contact me at 505 269-8234
>
> Robert Mudd
> Composite Aircraft Repair
> Moriarty, New Mexico.

Robert, as you will recall from our phone call, I suffered an uncommanded spoiler deployment earlier this year in a Twin Astir while on a winch launch.. I'm glad to see this AD issued.

[bumper[_4_]]

On Friday, October 30, 2015 at 8:51:41 PM UTC-7, Bill T wrote:

> Interesting comment about installing those inspection ports, are clear plastic covers available?
> BillT

Polycarbonate sheet (aka Lexan), easy to machine/cut with woodworking tools, hell for stout.

http://www.amazon.com/Polycarbonate-Sheet-Transparent-Standard-Tolerance/dp/B00CPRCQ9E

[[email protected]]

On Friday, October 30, 2015 at 7:06:39 PM UTC+2, Robert M wrote:
> A new AD note has been issued by the FAA concerning the airbrake locking system of all models of the G-103 glider certificated in any category. This means it applies to G-103s in the EXPERIMENTAL category too.
>
> AD 2015-22-04 becomes effective 4 December 2015. And has two different compliance times. It is available at: http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/MainFrame?OpenFrameSet
>
> The AD references two Service Bulletins issued by the Type Certificate holder, Fiberglas Technik Rudolf Lindner GmbH in Germany. http://ltb-lindner.com/
>
> The SBs are available at Lindner's web site.
>
> SB-G07 Instructions for installing an inspection opening to the underside of the wings.
> SB-G08 Instructions for checking the locking force of the airbrake system and adjusting it if necessary, and inspection the locking lever for cracks. It also calls for this inspection to be performed at each Annual Inspection.
>
> Lindner is working on a permanent fix which I assume would include replacing the locking lever in question. That may take a while.
>
> Many G-103s already have the inspection hole installed. They are a great help when doing the inspection for cracks in the locking lever and mandatory for adjusting the over center locking force. I highly recommend installing the inspection holes even if your initial inspection shows no cracks and the locking force is within limits,
>
> If you have questions contact me at 505 269-8234
>
> Robert Mudd
> Composite Aircraft Repair
> Moriarty, New Mexico.

The new AD is for the Twin IIs. The Twin Is had this for ages.
The incident which triggered the AD had one airbrake pop open at the start of the tow. The instructor opened the other one, continued the tow and landed safely. Thankfully, the tug was a Pawnee :-)
Subsequent inspection found another cracked bellcrank on another glider in the same club.
Uri

[Bill T]

Bill was your un commanded deployment from a cracked part?
BillT

[[email protected]]

On Sunday, November 1, 2015 at 4:15:34 PM UTC-7, Bill T wrote:
> Bill was your un commanded deployment from a cracked part?
> BillT

Not sure. The glider was not immediately inspected. The locking mechanism felt strange though.

[Tony[_5_]]

How would a cracked bellcrank cause both airbrakes to open?

[[email protected]]

On Sunday, November 1, 2015 at 7:33:34 PM UTC-7, Tony wrote:
> How would a cracked bellcrank cause both airbrakes to open?

Hard to say until someone who really knows how the thing is supposed to work looks at it. A developing crack in a bell-crank might allow the mechanism to bend so it couldn't completely lock closed.

[[email protected]]

On Sunday, November 1, 2015 at 4:15:34 PM UTC-7, Bill T wrote:
> Bill was your un commanded deployment from a cracked part?


Bill T.
You need to keep in mind that the "Uncommanded" deployment was followed by an "Uncommanded" opening of the canopy which was followed by an "Uncommanded" release failure. No one was ever able to duplicate any of this so there was an "Uncommanded" invitation to leave the club.

[[email protected]]

On Sunday, November 1, 2015 at 4:15:34 PM UTC-7, Bill T wrote:
> Bill was your un commanded deployment from a cracked part?
> BillT

BT,
Keep in mind the "Un Commanded" deployment was followed by an "Un Commanded" opening of the canopy which was followed by an "Un Commanded" release failure. No one was ever able to duplicate any of this so there was an "Un Commanded" invitation to leave the club.

[K m]

On Sunday, November 1, 2015 at 9:17:01 PM UTC-7, wrote:

>
> Hard to say until someone who really knows how the thing is supposed to work looks at it. A developing crack in a bell-crank might allow the mechanism to bend so it couldn't completely lock closed.

Whats hard to say is why your version of this event keeps changing. The ship in question WAS inspected by 2 AIs (One with extensive Grob experience) and the shop we had to take it to after you tore it up. Further, This ship has the inspection ports installed from the previous Brake AD. You know all of this of course, you are just dishonest.

[Robert M]

The kits for installing the inspection holes will include the correct epoxy resin and filler materials. The plexiglas cover/window is also included. As is noted in the instructions placement of the holes is critical as they are not in the same position on the LH wing as on the RH because of spar placement. Careful reading of the SB G07 is important.

I am collecting orders now for the kits and will have some on hand before the effective date of the AD note.

Robert Mudd
Composite Aircraft Repair
ph 505 269-8234

[[email protected]]

We did ours this summer as in Canada EASA AD's on EASA made gliders come into effect upon issue. Fortunately the closing forces were within spec and there was no damage to the parts. It wasn't that bad except for the derigging, rigging, derigging, rigging cycle needed to get it to the maintenance shop and back and then into the air again.

One thing I was curious about is that our Twin II already has inspection ports in the wings near the airbrake system parts in question but unlike the inspection ports in our Twin Astir RG they don't seem to be large enough to allow removal of the brake parts through them.