Date & Time: Jun 19, 1985 at 1510 LT
Operator:
Registration:
N199TA
Flight Phase:
Flight
Survivors:
No
Schedule:
Del Rio - McGregory
MSN:
T26-110
YOM:
1968
Crew on board:
1
Crew fatalities:
1
Pax on board:
0
Pax fatalities:
0
Other fatalities:
0
Total fatalities:
1
Captain / Total flying hours:
4843
Captain / Total hours on type:
66
Circumstances:
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.
Probable cause:
Occurrence #1: decompression
Phase of operation: climb - to cruise
Findings
1. (c) fuselage - decompression
2. (c) fuselage, skin - separation
3. (c) fuselage, stringer - fatigue
4. (c) maintenance, major repair - improper - other maintenance personnel
5. (f) facility, inadequate design (standard/requirement) - other maintenance personnel
6. (c) fuselage, stringer - previous damage
7. (c) maintenance, inspection - not performed - other maintenance personnel
8. (f) facility, inadequate design (standard/requirement) - faa (other/organization)
----------
Occurrence #2: airframe/component/system failure/malfunction
Phase of operation: descent - emergency
Findings
9. (c) fuselage - separation
----------
Occurrence #3: loss of control - in flight
Phase of operation: descent - uncontrolled
----------
Occurrence #4: in flight collision with terrain/water
Phase of operation: descent - uncontrolled
Final Report:
N199TA.pdf90.19 KB