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ASN Wikibase Occurrence # 45533
Last updated: 5 March 2020
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Type:Silhouette image of generic PA23 model; specific model in this crash may look slightly different
Piper PA-23-160 Apache
Owner/operator:Accelerated Flight Crew Training, Inc.
Registration: N4302P
C/n / msn: 23-1803
Fatalities:Fatalities: 3 / Occupants: 3
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:Rio Rico, Arizona -   United States of America
Phase: En route
Departure airport:Nogales, AZ (OLS)
Destination airport:Chandler, AZ (P19)
Shortly after takeoff, and about 3 miles from the airport, the airplane crashed into desert terrain near a rural residential area. The airplane had been flown to the departure airport earlier in the day for a certified flight instructor (CFI) multiengine check ride by the examinee, his CFI, and a multiengine rated private pilot passenger. No discrepancies were noted with that portion of the flight. During the engine run-up for the check ride, both the designated pilot examiner (DPE) and examinee noted that the left engine was not producing sufficient power for the pre-takeoff engine check. They cycled the engine at higher and lower mixture settings before they could conduct a normal run-up. After completing a simulated engine failure, the check ride continued with a normal takeoff. Towards the departure end of the runway, the DPE observed a loss of climb performance and noted that the left engine's manifold pressure was at 21.5-22.0 inches. They were going to make an off airport landing; however, they were able to gain enough altitude to land back at the airport. He also noted that, on the downwind leg for landing, the right engine oil temperature was near the upper limit, and the oil pressure showed a decrease toward the lower limit. On final, the oil pressure for the right engine dropped further near the lower redline limit. Once they landed, the oil pressure and oil temperature returned to normal. The pilots decided to do another run-up check, but during the check, the left engine was not developing power equal to that of the right engine, so they discontinued the check ride and taxied back to the ramp. The DPE discussed the situation with the CFI, who then called the flight school's mechanic and discussed the situation with him. Both the CFI and mechanic felt that the check ride should be discontinued, but it was safe to fly the airplane back to home base. The DPE observed the occupants board the airplane and reported that the CFI sat in back, with the examinee in the right front seat, and the private pilot in the left front seat. The airplane yawed to the left three times during the takeoff roll; each time the airplane returned to the runway centerline and the ground roll continued. The airplane lifted off after a long ground roll and gained altitude very slowly. The witnesses indicated that the airplane sounded normal during the takeoff. A few minutes later a loud shriek was heard on the UNICOM frequency, and a few minutes after that they were notified of an airplane down by local law enforcement. A post impact ground fire thermally destroyed the aircraft, and severely damaged the engine accessories and controls. No discrepancies were found during an examination of the airframe. Mechanical and valve train continuity were established for both engines. A differential compression check was conducted on both engines. The compression check for the left engine revealed low pressure on the numbers 2 and 4 cylinders. Both cylinders were staked with no difference noted in the number 2 cylinder. The number 4 cylinder had an improved compression reading. The numbers 2 and 4 cylinders were removed for further inspection. No internal discrepancies were noted with either the number 2 or 4 cylinders. Due to the degree of thermal destruction, no meaningful tests could be performed on the fuel or ignition system components. Ground scars and impact damage indicated that the airplane hit the ground in a steep left bank attitude and tumbled, which could be consistent with a loss of power on the left engine and a failure of the flying pilot to maintain an adequate airspeed above single engine minimum control airspeed. The anatomical evidence on the occupants was inconclusive as to who may have been manipulating the flight controls at the time of impact.

Probable Cause: a loss of engine power in the left engine for undetermined reasons, and the failure of the flying pilot to maintain an adequate single engine minimum control airspeed and aircraft control. Also causal was the decision of all three of the pilots to continue the flight with known engine discrepancies.



Revision history:

28-Oct-2008 00:45 ASN archive Added
21-Dec-2016 19:24 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
09-Dec-2017 16:49 ASN Update Bot Updated [Operator, Source, Narrative]
29-Oct-2019 18:49 Uli Elch Updated [Aircraft type, Location]

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