LA VERNE, CA, USA
N1392T
PIPER PA-34-200
THE FLIGHT INSTRUCTOR (CFI) SAID THAT DURING THE INITIAL CLIMB AND AFTER GEAR RETRACTION THE LEFT ENGINE LOST POWER. HE TOOK CONTROL AND FEATHERED THE LEFT PROP, BUT WAS UNABLE TO ESTABLISH A SINGLE-ENGINE RATE-OF-CLIMB. HE ATTEMPTED TO FLY THROUGH A LOW POINT IN HILLY TERRAIN, BUT THE AIRPLANE COLLIDED WITH A POWER LINE AND CRASHED INTO A RAVINE. THE LANDING GEAR WAS FOUND IN THE EXTENDED AND LOCKED POSITION, AND A GROUND WITNESS SAW THE GEAR EXTENDED DURING THE FLIGHT. THE LEFT ENGINE FUEL FLOW DIVIDER WAS FOUND TO BE PARTIALLY PLUGGED WITH A GREY/WHITE MATERIAL (CONTAMINATION). LABORATORY ANALYSIS IDENTIFIED THE MATERIAL AS POLYETHYLENE TEREPHTHALATE (PET), A THERMOPLASTIC MATERIAL. ORIGIN OF THE CONTAMINATE WAS UNKNOWN. ACCORDING TO THE AIRCRAFT SINGLE ENGINE PERFORMANCE CHART, THE AIRPLANE SHOULD HAVE BEEN ABLE TO CLIMB AT ABOUT 150 FEET PER MINUTE. A PILOT-RATED PASSENGER IN THE REAR HEARD THE STALL HORN SOUNDING AFTER THE CFI TOOK CONTROL AND ATTEMPTED TO ESTABLISH A SINGLE-ENGINE CLIMB. VYSE IS 103 MPH AND VSO IS 73 MPH.
On July 7, 1993, about 1937 hours Pacific daylight time, a Piper PA34-200, N1392T, collided with a power cable and the terrain while attempting a return to runway maneuver at the Brackett Airport, La Verne, California. According to statements from the pilots on board the aircraft, the flight experienced a complete loss of power in the left engine during the takeoff initial climb. Visual meteorological conditions prevailed at the time and no flight plan was filed for the operation. The aircraft was destroyed in the collision sequence and post impact ground fire. The commercial pilot, flight instructor and the two multi engine students sustained minor injuries. The flight was originating at the time of the mishap as a local area multi engine dual instructional flight. In a verbal statement, the flight instructor reported that during the initial climb following the takeoff from runway 26R, the left engine suddenly quit. He stated that he took control of the airplane, secured the left engine, and feathered the corresponding propeller. He then attempted to return to the airport. The flight instructor said the aircraft would not climb on one engine. It collided with power lines and fell to the ground inverted. The instructor reported that immediately following the loss of power in the left engine he checked the fuel selector valves and magnetos for proper positioning and retracted the landing gear. Post crash examination of the wreckage revealed that all three landing gear were in the down and locked position, the left propeller was feathered and the wing flaps were retracted. The passenger in the rear seat was a multiengine student and held a private pilot certificate. In his written statement, the passenger reported in part: "As we tried to climb [after the engine failure and Rohrer taking the controls] the stall horn sounded and the plane shuddered to the left. Jon [Rohrer] lowered the nose slightly ...." A multi engine airplane owner witnessed the accident airplane during the initial climb and maneuvering over Puddingstone Reservoir to the collision with the power cable. He stated that the low altitude and slow speed caught his attention while on Puddingstone Drive so he stopped and watched the airplane and observed that the landing gear was in the down position. PERSONNEL INFORMATION The instructor pilot who occupied the right front seat reported a total flight time of 560 hours with 100 hours as an instructor and 18 hours in the make and model of the accident airplane. The multi engine student who occupied the left front seat possessed a private pilot certificate with a single engine land rating. According to the operator's records, he reported a total flight time of about 750 hours. AIRCRAFT INFORMATION The airplane, a Piper PA34-200, was manufactured as a 1972 year model. At the last annual inspection on June 16, 1993, the left recording tachometer had accumulated about 3573 total hours of operation. The operator reported that the airplane had flown 59 hours since the annual inspection for a total time of 3632 hours. A Piper Aircraft performance chart for single engine climb rate and speed versus density altitude and weight was obtained for reference. According to the chart: at the airplane's takeoff weight, a density altitude of about 2500 feet, with the gear and wing flaps retracted, the failed engine cowl flap closed, and the propeller feathered, the airplane should climb at about 150 feet per minute. The single-engine performance charts listed a Best Single-Engine Rate of Climb airspeed (Vyse) for the takeoff weight and density altitude as 103 mph. The computed power-off stall speed for the aircraft (Vso) was noted to be 73 mph. According to the FAA Type Certificate Data, the airplane has a gross takeoff weight of 4,200 pounds. The pilot stated that they departed with 600 pounds of fuel. According to the occupant's FAA medical certificates, their combined weights were about 534 pounds. According to the last weight and balance information, the airplane empty weight was 2833.9 pounds. The gross weight at takeoff of the accident flight was calculated to be about 3,968 pounds. WRECKAGE AND IMPACT INFORMATION The airplane collided with a 66,000 volt power transmission cable. Post crash examination of the wreckage revealed cable strike signatures through the left outboard fuel tank to the main wing spar. According to the pilots' statements, at the point of collision with the cable the wing caught on fire and they rolled inverted. A topographical chart was referenced that delineated both the wire struck by the aircraft and the point identified by the pilots as where the left engine lost power. Using the pilot report and a witness, the flight track was plotted on the chart and a distance of 7,200 feet was measured linearly. According to the pilot, the left engine lost power about 200 feet agl at a point on the map that shows a ground elevation of 963 feet MSL. The wire struck by the aircraft was at an approximate elevation of 1,125 feet MSL. On scene examination of the airplane wreckage revealed that it impacted in a near inverted attitude in a ravine straddling a chain link fence next to a wash. A post crash fire consumed most of the airplane. Switch and control positions could not be obtained. Control system continuity was not established. The exposed actuating rods for the hydraulic landing gear extension and retraction cylinders were measured. The length of the nose gear rod was about 7.25 inches and the main landing gear rods were about 8.30 inches. According to engineering representatives from Piper, these dimensions correspond to a landing gear fully extended-and-locked condition. In addition, the nose landing gear strut was found separated at a point just below the upper strut cylinder. The fracture and surrounding lower strut tube area was observed deformed in an aft direction to the normal flight path of the aircraft. Wire contact marks were noted on the lower strut just below the fracture point. TEST AND RESEARCH A post crash examination of the airframe and engines was conducted after retrieval to a storage area. During the course of the examination, the left engine fuel flow divider mounted on top of the left engine was found to be contaminated and partially plugged with a grey/white material. The flow divider and the contaminant was sent to Seal Laboratories for analysis. The material was identified as polyethylene terephthalate (PET), a thermoplastic material. According to Seal Laboratories, this type of material is common to the injection molding business in a pellet form or powder form for coating processes. A copy of the laboratory report is attached to this report. Review of the aircraft design specifications revealed that the material is foreign to the airplane systems and components. The origin of the contaminate is unknown. ADDITIONAL INFORMATION The aircraft wreckage was released to the registered owner on September 8, 1993, following completion of component tests and examinations.
THE FLIGHT INSTRUCTOR'S FAILURE TO OBTAIN/MAINTAIN BEST THE SINGLE-ENGINE RATE-OF-CLIMB AIRSPEED, AND HIS FAILURE TO ENSURE THAT THE LANDING GEAR WAS RETRACTED. A FACTOR RELATED TO THE ACCIDENT WAS CONTAMINATION IN THE FUEL SYSTEM, WHICH BLOCKED FUEL FLOW THROUGH THE FLOW DIVIDER AND RESULTED IN FUEL STARVATION TO ONE ENGINE.
Source: NTSB Aviation Accident Database
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