Aviation Accident Summaries

Aviation Accident Summary LAX94FA159

LOS ANGELES, CA, USA

Aircraft #1

N8129W

PIPER PA-28-180

Analysis

DURING INITIAL CLIMB AT 300 FEET AGL, THE UPPER COWL RAISED UP BETWEEN 1 AND 2 INCHES. THE PILOT REPORTED HE STAYED IN THE PATTERN. ON BASE LEG, THE UPPER COWL DISLODGED FURTHER FROM THE ACFT AND PRODUCED DRAG. UNABLE TO MAINTAIN ALTITUDE, A FORCED LANDING WAS MADE DURING WHICH THE ACFT COLLIDED WITH POWER LINES AND HOMES 1/2 MILE FROM THE RUNWAY. PRIOR TO THE FLIGHT, THE PILOT, WHO OWNED THE ACFT AND WHO WORKED AS AN A & P MECHANIC, HAD REMOVED AND PARTIALLY REPLACED THE ENGINE COWL. A FRIEND OF THE PILOT, WHO ALSO HELD AN A & P CERTIFICATE AND WAS A PILOT, ASSISTED BY PLACING THE LEFT SIDE OF THE UPPER COWL BACK ON THE ENGINE COMPARTMENT. THE SURVIVING PILOT REPORTED THAT HE HAD NOT OBSERVED THE PILOT-RATED PASSENGER PHYSICALLY SECURE THE LEFT SIDE OF THE UPPER COWL TO THE ENGINE COMPARTMENT. DURING THE WRECKAGE EXAM, ALL OF THE FIRE-DAMAGED COWL STRUCTURE WAS FOUND AT THE CRASH SITE EXCEPT FOR THE TWO FORWARD-POINTED UPPER COWL ENGAGEMENT PINS AND THEIR SUPPORTING STRUCTURE. ALSO NOT FOUND WAS THE NYLON GROMMET/BUSHING WHICH NORMALLY WAS SEATED IN THE LOWER COWL'S LEFT SIDE FORWARD PLATE ASSEMBLY.

Factual Information

HISTORY OF FLIGHT On March 11, 1994, at 1849 Pacific standard time, a Piper PA-28- 180, N8129W, owned and operated by the pilot, collided with power lines and houses during a forced landing on final approach to runway 21 at the Santa Monica Municipal Airport. The crash site was approximately 0.4 miles northeast of the approach end of the runway, in the City of Los Angeles, California. Visual meteorological conditions prevailed during the nighttime personal flight. The airplane was destroyed during the impact sequence and during the postimpact ground fire. The commercial pilot was seriously injured. The passenger/second pilot was fatally injured. No one on the ground was injured. The pilot reported to the National Transportation Safety Board that prior to taking off from the Santa Monica Municipal Airport, he had performed an engine run-up, and no discrepancies were noted. The engine and all airplane systems were operating normally, and he taxied for takeoff. At 1844:41, the local controller issued the pilot of N8129W a clearance to take off, and the pilot took off. The pilot reported to the National Transportation Safety Board that at an estimated altitude of 300 feet above the runway's surface, he observed a portion of the engine's upper cowling raise up between 1 and 2 inches. The pilot stated that he believed insufficient runway remained ahead on which to stop, so he continued climbing. The pilot made a left turn staying in the left hand traffic pattern, and he climbed to approximately 1,000 feet mean sea level. At 1848:25, the pilot informed the controller that he was having an engine problem/failure, and the controller cleared the airplane to land. This was the last transmission received from the airplane pilot. The pilot subsequently informed the Safety Board that during the landing approach, as he was leveling out of the base leg turn, he heard the cowling hit something on the airplane, and he believed it had actually separated from the airplane. Thereafter, the right wing and the nose dropped. The engine was operating normally, and despite adding full engine power, altitude could not be maintained. The pilot stated that seconds prior to the crash, the passenger who was also a pilot, took the controls and banked the airplane toward an area which appeared more suitable for the forced landing. On short final approach to runway 21, the airplane collided with energized power lines and the roofs of two houses. The airplane came to rest in the front yard of one of the residences, at 2754 Barrington Avenue, Los Angeles, California. The accident site was approximately 34 degrees 1.5 minutes north latitude, by 118 degrees 26.4 minutes west longitude. This location was about 0.45 statute miles northeast of the approach end of runway 21. PERSONNEL INFORMATION The first pilot owned the airplane. The pilot held a commercial pilot certificate with airplane single-engine and multiengine land ratings, and an instrument rating. The pilot reported having a total of 320.8 hours of flight time, of which 233.0 hours were in the accident model airplane. During the preceding 90-day period, the pilot reported having flown his airplane for 11.7 hours, of which 3.1 hours were at night. The pilot held an airframe and powerplant mechanic certificate, and worked in that capacity for an airline. The second pilot held a private pilot certificate with an airplane single-engine land rating. His personal flight record logbook was not examined. According to Federal Aviation Administration (FAA) records, on April 19, 1993, when the pilot was last issued a third-class aviation medical certificate, he indicated having a total flight time of 220 hours. The pilot also held an airframe and powerplant mechanic certificate. AIRCRAFT INFORMATION The pilot provided the Safety Board with the maintenance logbooks for the accident airplane. A review of the logs indicated that on November 17, 1993, the airplane had received an annual inspection at a total airframe time of 3521.6 hours. The most recent entry observed in the aircraft and engine logbooks was found dated January 13, 1994. On that date the logs indicated the pilot had performed a 100-hour inspection on his airplane at a total time of 3572.8 hours. No logbook evidence was found for any of the maintenance the pilot reported having performed during the second week of March, 1994. The pilot reported that he kept the airplane's logs at his residence, and he had not recorded recent maintenance into the logs. WRECKAGE AND IMPACT INFORMATION An examination of the accident site, airplane wreckage, and witness statements revealed that as the airplane was descending toward the approach end of runway 21 it collided with energized power lines and the roofs of two adjacent homes. The outboard, 2.5-foot-long portion of the right wing was found on top of the roof of a house at 2758 Barrington Avenue. The airplane's severed left wing was found on top of the roof of an adjacent house at 2754 Barrington Avenue. The airplane came to rest in an upright attitude, in an easterly direction, and next to the house's front porch. A postimpact ground fire destroyed the airplane's cockpit, center fuselage, and portions of the engine compartment. In addition, the fire spread to the adjacent homes and they sustained fire damage. All of the airplane's flight control surfaces were accounted for at the accident site. The continuity of the flight control cable system was established from the stabilator and rudder assemblies to the middle of the fuselage, which was found fire damaged. Electric power to the local neighborhood was observed to have been interrupted. The leading edge portion of the right wing was found marked with several electrical arc puncture holes and wire-like abrasions. MEDICAL AND PATHOLOGICAL INFORMATION On March 13, 1994, an autopsy was performed on the second pilot/passenger by the Los Angeles County Coroner's Office. The autopsy did not disclose any evidence of physical incapacitation that would have adversely affected his ability to operate the airplane. The listed cause of death was inhalation of smoke, soot, and noxious fumes with a contributing factor of thermal burns. The second pilot/passenger's automobile was found parked on the airport ramp. The coroner's investigator reported that during his search of the automobile a smoking pipe was found which contained the burnt residue of what smelled like hashish. Also, a plastic film vial was found which contained what appeared to be hashish residue. On October 17, 1994, the Safety Board received toxicology results from the FAA tests on specimens from the second pilot. Evidence of marihuana and amphetamine was found in his blood and urine. (See the attached toxicology report for additional details.) TESTS AND RESEARCH On March 15, 1994, at the facilities of Aero Retrieval, Compton, California, an examination of the engine and airframe components was performed. The following was noted: Engine Examination All spark plugs were removed. The engine participant reported that the electrode wear appeared normal. The carburetor's fuel inlet screen was removed. A white-colored powdery substance was observed on the screen. No other foreign matter was noted. The carburetor was noted to have been located in the area where the postimpact fuel fire and fire department suppression activities had taken place. A stream of oil was observed leaking onto the examination room floor from undetermined locations within the impact-damaged engine. Thumb compression was felt in all four cylinders. The continuity of the gear train system was established. At the conclusion of the examination, the engine participant reported finding no evidence of any preimpact malfunctions. But for the fire and impact-related damage, the engine appeared capable of operating. Engine Cowl Examination Regarding the engine compartment's upper cowl, all of the cowl fasteners and the oil access door were located at the site of the main wreckage. The oil access door was observed bent/curled in an upward direction. The right rear latch assembly was observed bent in a unique direction. The Safety Board noted that when the bent latch assembly was placed against an exemplar cowl, and the cowl was thereafter raised with the right, aft portion secured to an exemplar airplane, the bend observed in the latch assembly was consistent with the upward tilted cowl. The deformation to the aft latch was observed most consistent with the dislodged cowl when the front of the cowl was simultaneously tilted upward and rotated in a clockwise direction (see photographs). Neither the upper cowl's forward-mounted steel engagement pins nor debris associated with their supporting structure were located in the residue of the fiberglass cowl. A nylon-like bushing/grommet was found inside the lower cowl (right side) plate assembly. The corresponding left side bushing/grommet was not found (see photographs and cowl wreckage diagram). ADDITIONAL INFORMATION Additional text for photographs 13, 16, and 18: 13) During attachment of the upper to the lower cowl, the two aft-oriented upper cowl engagement pins are inserted inside the two lower cowl plate assembly holes. 16) When all attachment latches were unfastened except for the one located at the cowl's right, aft position (as shown), the forward portion of the upper cowl entered the propeller blade's plane of rotation as the cowl was tilted upward. 18) Note that the metal latch in the area where the butterfly assembly was located (see pointing finger in right hand) is bent in a direction consistent with the latch having been closed while the cowl was in a raised and clockwise twisted position. The main airplane wreckage was released to the owner on March 20, 1994. All retained components were released and personally delivered to the owner on May 16, 1994.

Probable Cause and Findings

the failure of the upper engine compartment cowl to remain attached to the lower cowl during initial climb as a result of inadequate maintenance and replacement practices by the aircraft owner.

 

Source: NTSB Aviation Accident Database

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