Safety Officer Discovers MH-53E Modification Performing Contrary To Stated Purpose

Cris Sonnichsen, a sheet metal mechanic assigned to the H-53 program, has been named February’s Naval Air Depot Cherry Point, N.C., Safety Professional of the Month. Sonnichsen recently discovered a major discrepancy while performing maintenance on an MH-53E helicopter. While installing the AYC 1306 modification, Sonnichsen noticed that the modification was actually performing contrary to its intended purpose.

On the MH-53E, the FS 820 bulkhead has a history of developing cracks due to preload stress. The Japanese military, along with Sikorsky Helicopter, had developed the AYC 1306 modification, a strengthened support bracket, to remove the preload conditions and therefore extend the life of the bulkhead.

Sonnichsen noticed that due to the angle of the support bracket, a new preload was being introduced to the bulkhead – one that would actually cause cracks to develop sooner. After analyzing the support bracket, it was determined that the angle of the bracket had been improperly formed, resulting in the new preloading condition.

An inspection of a second MH-53E helicopter found that its AYC 1306 modification was also improperly formed. This led not only to the removal of its modification, but also to the inspection of all AYC 1306 modification kits in the fleet. NADEP artisans have corrected the problem for both aircraft and they have been cleared to return to the fleet.

“I’m no hero,” said the 14-year veteran of NADEP Cherry Point, echoing the common statement made by many previous safety pros. “I was just doing my job.”

Despite his modest claims, Sonnichsen’s attention to detail saved the U.S. Navy countless hours of maintenance and hundreds of thousand of dollars in replacement material and labor cost. not to mention the lives that could have been lost had the modification failed during a mission.

(Our thanks to By Capt. Theodore Haskell, Aviation Safety Officer, and our congratulations to Mr. Sonnichsen for a job well done!)

FMI: www.nadepcp.navy.mil