Service difficulty report · Lock Nut · Cessna 172M

Difficulty date
July 31, 2019
Submitted
August 17, 2020
Operation
General aviation
Make and model
Cessna 172M
Aircraft time
7,953 hours
Engine
Lyc O320E2D
Propeller
Mcauly 1C160DTM
Part
Lock Nut
Part number
NAS679
Condition
Undertorqued
Location
Horizontal Stab
Stage of operation
NR
How discovered
9
Nature of condition
O
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

(CAN) CREAKING NOISE REPORTED FROM TAIL OF AIRCRAFT. MAINTENANCE NOTED THAT THE TORQUE ON THE NAS679 LOCK NUTS AS USED BY CESSNA ON THE HORIZONTAL STABILIZER WERE LOOSE. THE NAS679A3 NUTS WERE PART OF A RECALL FROM CESSNA SE69-28, BUT ONLY IN THE -3 SIZE. THE AFFECTED NUTS WERE -5 DIAMETER AND THEREFOR NOT EFFECTED. CESSNA CONTINUED TO USE THE -5 NUTS TILL APPROXIMATELY 1980 AT WHICH TIME THE CHANGE UP WAS TO A MS21042L5. IT HAS BEEN THE WRITERS HABIT TO CHANGE OUT THE NAS NUTS ANYTIME THEY ARE ACCESSIBLE AS CESSNA ALSO HAS A RECALL ON THE SAME NUTS IN A CARRY THROUGH SPAR ISSUE.

More about the Cessna 172M