Textron Aviation on August 7 issued a service letter for certain Cessna 172S models. The letter states that, “The cotter pin that secures the attachment clevis pin for left and right brake master cylinders may have been installed (bent) incorrectly.” Incorrectly installed cotter pins may lead to loss of braking control.
Owners of affected serial numbers are required to comply with the instructions for inspection within 10 flight hours or 60 days of receipt of the service letter.
Here are the series numbers: 172S12270 thru 172S12298, 172S12305, 172S12310
Read the full service letter here.