Attn CC11 owners:

Earlier this week the latest updates for the CC11-100 and CC11-160 POH were mailed out. If you did not have the latest revision installed at the factory, you should be receiving a package containing several updated sections as well as Service Instruction 25 (SI0025).

The changes to the POH can be noted in Section 0 and include international units, minor corrections, and changes for the new window limitations placard. SI0025 has been created to retrofit a placard on the left side window frame to provide operation limitations for requiring windows be closed for takeoff and landing, limiting maximum speed with windows open, and allowing only one window open at a time.

In an effort to maintain transparency, the reason this service instruction has been created is to prevent damage to aircraft due to wind buffeting. Particularly with the Carbon Cub, but also a concern for Sport Cubs, the prop wash and wind at high RPM’s and airspeed creates a large amount of buffeting on the aircraft. This is notably pronounced with both windows open at the same time. We are responding to instances where rear windows have begun delaminating from the airframe due to the wind pressure in the aircraft with both windows open.

The maximum speed with windows open has been determined through both owner and Cub Crafter’s experience as the point at which excessive buffeting occurs. There have been issues with operating at speeds in excess of 70 Knots (81 mph) which has caused cracking in the main windows. This issue has been limited to aircraft with an early style of both window frame design and adhesive technique which has since been revised.

We understand many pilots prefer to fly their planes with as much freedom as possible, and nothing can beat both windows and the door wide open on those hot summer days. You can find some discussion on the topic here. The latest versions of the CC11-100 and CC11-160 POH and SI0025 can be found on the Owner Support section of the website. These limitations are in place to maintain the safety of both you and your aircraft.

Feel free to post any questions. Happy flying!

Adam Sloon -- Engineering
CubCrafters