ASN Wikibase Occurrence # 287260
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| Date: | Sunday 18 November 2012 |
| Time: | 20:18 LT |
| Type: |  Piper PA-32-300 Cherokee Six B |
| Owner/operator: | Star Marianas Air, Inc |
| Registration: | N4267R |
| MSN: | 32-40641 |
| Year of manufacture: | 1969 |
| Total airframe hrs: | 6805 hours |
| Engine model: | Lycoming IO-540 |
| Fatalities: | Fatalities: / Occupants: 7 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Obyan, -
 United States of America
|
| Phase: | Initial climb |
| Nature: | Unknown |
| Departure airport: | Saipan International Airport (SPN/PGSN) |
| Tinian Island International Airport (TIQ/PGWT) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The 14 Code of Federal Regulations Part 135 airline operated a fleet of single-engine airplanes that shuttled passengers between two islands located about 10 minutes' flying time apart. The flight was carrying six passengers and was being conducted in visual meteorological conditions at dawn. After a normal start, taxi-out, and engine run-up, the airplane departed using the full length of the 8,000-ft-long runway. About 4 minutes after takeoff, the pilot radioed the air traffic control tower that he wanted to "come back in for an immediate landing"; the airplane landed uneventfully on the departure runway about 3 minutes later.
The airplane exited the runway at the first taxiway, situated about 3,150 ft past the runway threshold, and the pilot subsequently conducted an engine run-up. The pilot returned to the runway and initiated an intersection takeoff using the 5,550 ft of remaining runway. About 45 seconds after the pilot began the takeoff, the airplane experienced a partial loss of engine power, so he began a second turnback. During the turnback, the airplane stalled at low altitude and impacted airport property near the end of a runway parallel to the departure runway. A postimpact fire ensued; one passenger did not exit the airplane and died.
The pilot did not recall making the first turnback, and the investigation was unable to determine the reason for the first turnback. One passenger reported that the pilot was using his mobile telephone at an inappropriate time during the beginning of the flight, and two other passengers reported that the cabin door became unlatched at some point during the flight. Neither passenger reported that any door problems occurred after the second takeoff. Although there was no evidence to support the passengers' allegations regarding the telephone or the cabin door events, an airline representative suggested that the first turnback was conducted due to the door coming open and that the subsequent engine run-up was conducted to conceal the actual reason for the turnback. The representative added that the second turnback may have been due to the pilot's distraction and loss of situational awareness as he attempted to relatch the door that might have become unlatched again.
Postaccident on-site wreckage examination and test runs and examination of the engine did not reveal any preimpact mechanical deficiencies that could be directly linked to the power loss. Although anomalies with the engine-driven fuel pump and one magneto were detected during their respective examinations, the units performed satisfactorily during bench testing. However, there were a sufficient number of undetermined details regarding the preimpact configuration and condition of the airframe and the engine to preclude a determination of the preaccident functionality and airworthiness of the airplane. Those details included the magneto-to-engine timing, the internal timing of the right magneto, the fuel selector valve takeoff setting, and the fuel quantity in the selected tank.
Review of airplane performance data indicated that the 5,550 ft of runway beyond the taxiway intersection was more than sufficient for the takeoff. The performance data showed a rapid roll into a sustained bank angle during the turnback, which did not support the airline's scenario that the airplane veered off course due to the pilot's loss of situational awareness. The investigation was unable to determine the initiation altitude of the turnback or whether there was sufficient altitude for the safe execution of such a maneuver. However, deductions of the airplane location, altitude, and heading based on the ground scar information indicated that a safe landing would not have been possible from the point in the flightpath where the airplane stalled. Neither the airline nor the airplane manufacturer provided any specific guidance to pilots regarding minimum safe turnback altitudes.
The pilot's decision to conduct an intersection takeoff, instead of a full-runway-length takeoff, left 3,150 ft less runway. Although he did not state it explicitly, the apparent reason that the pilot opted for the intersection takeoff was for schedule expediency, by obviating the need for the extra few minutes required to taxi back for a full-runway-length takeoff. Based on the accident flightpath, the additional 3,150 ft of runway likely would have been sufficient to enable a straight-ahead landing after the power loss rather than a turnback. By foregoing the taxi-back, the pilot reduced his margin of safety by decreasing his options in the event of an engine anomaly or power loss. Review of aerial imagery revealed that, beyond the airport's northeast boundaries, there were very few locations suitable for an emergency landing following a low-altitude power loss, which likely contributed to the pilot's decision to attempt to return to the airport. Although the airline published the preferred flight tracks between the two airports that it primarily served, it did not provide any guidance regarding preferred flightpaths or emergency landing sites following an engine failure at low altitude.
Probable Cause: A partial loss of engine power shortly after takeoff for reasons that could not be determined because postaccident examination did not reveal any anomalies that would have precluded normal operation and the pilot's failure to maintain airplane control during the unsuccessful attempt to return for landing on the airport. Contributing to the accident was the pilot's decision to conduct his second takeoff using less than the full runway length available and the airline's lack of guidance regarding how to respond to engine failures at low altitudes.
Accident investigation:
 |
|
Sources:
NTSB WPR13LA045
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 04-Oct-2022 09:08 | ASN Update Bot | Added |
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