Telco Systems

Swearingen SA26T Merlin II

As the aircraft was climbing thru 14,800 feet for 19,000 feet, the pilot reported a rapid decompression. Two minutes later, he reported that he has lost the tail. Aircraft impacted in an inverted flat spin and the tail and a section of empennage were found about 3/4 mile away from main wreckage. Investigation revealed that a skin seam had split open along a 54' span in an area where 2 pieces of 'l' shaped channel had been riveted together to form a stringer. Normally the stringer would be made using a single piece of 't' shaped channel. The non-standard stringer had been fabricated during repairs made on the aircraft following a gear up landing 7 years prior to this accident. Analysis revealed that the rivets holding the 'l' channels together and failed in fatigue due to tensile cyclic loading whenever the aircraft was pressurized. Aircraft had a history of pressurization problems following the repair that was not properly performed or inspected. The pi1lot, sole on board, was killed.