In-Flight Engine Failure and Subsequent Ditching

8

In-Flight Engine Failure and Subsequent Ditching

Air Sunshine, Inc., Flight 527

Cessna 402C, N314AB

About 7.35 Nautical Miles West-Northwest of Treasure Cay Airport, Great Abaco Island, Bahamas

July 13, 2003

〔图〕插图

Aircraft Accident Report

NTSB/AAR-04/03

PB2004-910403

Notation 7671A

Aircraft Accident Report

In-Flight Engine Failure and Subsequent Ditching

Air Sunshine, Inc., Flight 527

Cessna 402C, N314AB

About 7.35 Nautical Miles West-Northwest of Treasure Cay Airport, Great Abaco Island, Bahamas

July 13, 2003

〔图〕NATIONAL TRANSPORTATION\nSAFETY BOARD\n NTSB/AAR-04/03

PB2004-910403

Notation 7671A

Adopted October 13, 2004

National Transportation Safety Board

490 L'Enfant Plaza, S.W.

Washington, D.C. 20594

References

References

Factual Information

4

Aircraft Accident Report

The station manager stated that he then alerted local agencies about the emergency and instructed another Air Sunshine pilot, who had just taken off from Marsh Harbor, Bahamas, for FLL, to divert that flight toward flight 527 and follow the airplane until it reached the airport. The Air Sunshine pilot transmitted a distress call for flight 527, which the pilot of a nearby flight (Gulf flight 9267) heard and relayed to the Federal Aviation Administration (FAA) Air Route Traffic Control Center (ARTCC), Miami, Florida.

The pilot stated that, after talking to the station manager, he slowed the airplane to about 95 KIAS to try to maintain altitude. The pilot stated that, once he descended from about 1,500 to 1,000 feet, he realized the airplane could not make it to the airport and that he would have to ditch the airplane. The pilot stated that he ditched the airplane parallel to the waves with the flaps retracted. He added that, at the time of the ditching, the winds were about 15 knots, and the outside air temperature was about 80° to 90° Fahrenheit (F). The passenger in the copilot seat stated that the pilot did a good job ditching the airplane. He stated that he noticed a placard on the instrument panel with instructions for ditching, which stated that the airspeed should be kept in the “blue zone,” and that the airspeed was within this zone during the ditching. Adult passengers described the contact with the water as “very hard.” They stated that the airplane landed “flat” and that it did not dive into the water.

During postaccident interviews, the passengers stated that the pilot did not instruct them to retrieve their PFDs or to assume a brace position before contact with the water. The passengers stated that the only time the pilot addressed them after the right engine failed and before the airplane contacted the water was to tell them to “calm down.”

The airplane was located at 26° 45.547' north latitude and 77° 31.642' west longitude. The accident occurred during daylight hours.

1.2 Injuries to Persons

Factual Information

9

Aircraft Accident Report

〔图〕Escape HatchBBBBCOPILOT123AAPILOTAA54Escape HatchMain Boarding Door\n

Figure 1. Interior configuration of the accident airplane.

According to the load manifest form for the accident flight, the airplane's takeoff weight was about 6,644 pounds, including 890 pounds of passenger weight,$^{25}$ 350 pounds of baggage weight, and 800 pounds of fuel weight. The airplane's takeoff center of gravity (CG) was 154.61 inches aft of the reference datum. After the airplane was retrieved from the water,$^{26}$ the baggage was removed from the airplane, dried, and weighed. The baggage weighed 440.85 pounds, 90 pounds more than the amount that was entered on the load manifest form. After applying the additional 90 pounds, the weight and CG were still within acceptable limits.$^{27}$

1.6.1 Engines and Propellers

The airplane was equipped with two Teledyne Continental Motors (TCM) TSIO-520-VB reciprocating engines. These engines are turbo-charged and fuel-injected with six horizontally opposed air-cooled cylinders. The engines are rated for 325 horsepower at a power setting of 2,700 rpm with 39 inches Hg manifold pressure up to an altitude of 12,000 feet.

Factual Information

13

Aircraft Accident Report

AIR SUNSHINE MAINTENANCE MANUAL

SECTION 9

PAGE 9

DATE Nov. 4,2002

REVISION 10

CYLINDER DIFFERENTIAL COMPRESSION CHECK - TSIO 520 ENGINE

DATE $\frac{1}{4}-14-03$ A/C# N314AB TAT

LEFT ENGINE (TSOH): $\ldots$ RIGHT ENGINE (TSOH):

This inspection is performed in conjunction with every A inspection.

1. $CAUTION$ – MAGNETOS and FUEL must be OFF before starting test.

1. Perform the compression test as soon as possible after the engine is shut down to ensure that rings and cylinders are well lubricated.

1. $CAUTION$ – It is recommended that someone hold the propeller during this check, to prevent possible rotation.

1. Record readings in applicable blocks.

〔图〕625CYL#134LEFT6670786.060品8080808080ENGINERIGHT37860120748080B08008ENGINE\n NOTE: If a valve is to be staked to dislodge any foreign material suspected to be between the valve face and seat, it is necessary to rotate the propeller so the piston will not be at T.D.C.

Figure 2. Cylinder differential compression check form.

Note: According to the assistant mechanic and the Director of Maintenance, the number recorded for right engine cylinder No. 3 was “55.” (Safety Board investigators who reviewed the document noted that the number could be either “55” or “25.”) The assistant mechanic's signature and A&P certificate number have been redacted.

Factual Information

19

Aircraft Accident Report

〔图〕插图

Figure 3. Exterior of the upper outboard engine cowling.

The right engine was removed and examined, under Safety Board supervision, at TCM's facility. After engine disassembly at TCM, some of the right engine components were brought to the Safety Board's Materials Laboratory in Washington, D.C., for further examination. For additional information about the metallurgical inspections of the right engine components, see section 1.16.3.

The right propeller was removed and examined, under Safety Board supervision, at McCauley Propeller's facility. The right propeller hub was intact and undamaged, and all three blades were intact and installed in the hub and appeared to be in the feathered position. The blade angles were measured as follows: blade No. 1 was 82.2°, blade No. 2 was 82.4°, and blade No. 3 was 82.3°. The feather angle for this propeller is 82.2° (+/-0.3°). All of the blade counterweights were present and in place. The propeller piston was undamaged, and the centrifugal weights and springs were in place. The piston rod and feathering spring were intact, in place, and undamaged. The feather-stop and start-lock mechanisms were intact and undamaged.

Factual Information

28

Aircraft Accident Report

and the through bolt piece was found with a nut attached. The outboard portions of the other three fractured studs were not recovered. The other fractured through bolt, which is where the nut would normally be, was not recovered. Figure 4 shows the condition in which the right engine No. 2 cylinder retention system components were found.

〔图〕Stud Fatigue,Outboard PieceStud IntactRecovered, No NutMissing from CaseOStud Intact,Through Bolt Fatigue,Nut in PlaceBe

Figure 4. The condition in which the right engine No. 2 cylinder retention system components were found.

Note: The cylinder base flange is outlined in blue, and the mounting surface is outlined in red.

Optical and scanning electron microscopic examinations of four of the hold-down stud and two of the through bolt fractures found features that were consistent with high-stress and low-cycle fatigue propagation. For all of the studs and through bolts with fatigue cracking, initiation was from multiple locations in a thread root along one side of the fastener. The fatigue propagated in a high-stress manner with parallel fissures and striations until ductile overstress occurred at about 50 percent of the fastener's cross-section. Some spots of corrosive material were visible at random areas across the fractures; however, little or no oxidation or corrosion was apparent in the fracture origin areas. A comparison of height measurements of the No. 2 cylinder studs' features with features on other cylinder studs in the engine crankcase revealed that the studs had been installed to similar depths.