History of Flight
On December 11, 2013, at about 1522 Hawaiian standard time, a Cessna 208B, registration N687MA, was destroyed following a loss of engine power and ditching into the Pacific Ocean near Kalaupapa, Hawaii. The flight had departed from Kalaupapa Airport on the island of Molokai about two minutes earlier, bound for Honolulu International Airport on Oahu. Visual meteorological conditions prevailed, and a company flight plan was filed.
According to the pilot, shortly after takeoff from runway 05 at about 400 feet above ground level (agl), he began a left turn for a downwind departure. After passing 500 feet agl, he motioned to reduce power when he heard a loud bang followed by an immediate loss of engine power. The pilot continued the turn toward land, verified fuel valves were on, and observed all engine gauges reading zero. Realizing the airplane would not reach land, he rolled the wings level and broadcast a mayday distress call. The airplane then contacted the ocean surface in a flat or slightly nose-up attitude.
All passengers and the pilot exited through the rear right door. The airplane floated for about 25 minutes before sinking. One passenger swam to shore; US Coast Guard and Maui Fire and Rescue helicopters recovered the remaining occupants about 80 minutes after the ditching. A passenger video, which began as the airplane descended, showed the airplane impacting with wings level and slightly nose-high, remaining intact and afloat throughout the recording.
Personnel Information
The pilot, age 60, held an airline transport pilot certificate with multiengine land and type ratings in Boeing 737 and 777 aircraft, along with commercial privileges in single-engine land airplanes and gliders. He also held a flight instructor certificate with multiengine, single-engine, and glider ratings. His most recent first-class medical certificate, issued December 9, 2013, required corrective lenses. The operator reported that he completed his most recent Part 135 proficiency check on May 9, 2013. The pilot had approximately 16,000 total flight hours, with 250 hours in Cessna 208Bs. In the preceding 90, 30, and 24 hours, he flew 150, 50, and 10 hours respectively, all in Cessna 208Bs.
Aircraft Information
The Cessna 208B, manufactured in 2002, was equipped with a Pratt & Whitney Canada PT6A-114A 675-horsepower turboprop engine, serial number PCE-PC1021, which had accumulated 4,899.6 hours and 9,303 cycles since new. Logbook review showed that in July 2012 the engine reached its recommended time between overhaul (TBO) of 3,600 hours; the operator obtained a factory-authorized 200-hour TBO extension, approved by the FAA. On July 23, 2012, at 3,752.3 hours, the engine was placed on a Maintenance on Reliable Engines (MORE) STC, extending the TBO to 8,000 hours, also FAA-approved. The MORE STC requires supplemental inspections but does not recommend engine condition trend monitoring (ECTM), unlike P&WC guidance. The operator followed the MORE program and did not conduct ECTM.
When the engine entered the MORE program, a hot section inspection (HSI) was performed. P&WC guidance required compressor turbine (CT) blade metallurgical evaluation (destructive testing of two blades); no documentation showed this was completed. The operator found the combined guidance confusing and interpreted that blade sectioning was unnecessary under the MORE STC because increased inspection intervals would manage the CT blades. Two other HSI tasks—combustion liner cooling ring gap check and trim thermocouple verification—were not accomplished as they were not required by the MORE STC. The MORE documentation also did not reference P&WC service information letter for borescope examination of CT blade trailing edges. At the time of the accident, the engine had operated under the MORE STC for about 1,137.3 hours. The most recent inspection, 3.9 hours before the accident, covered the MORE 100-, 200-, and 400-hour inspections, the latter including a hot-section borescope inspection of compressor blades only.
Meteorological Information
At 1454, weather at Molokai Airport, about 8 nautical miles southwest, was wind from 040 degrees at 15 knots gusting to 26 knots, visibility 10 miles, sky clear, temperature 27°C, dew point 19°C, and altimeter 29.95 inHg.
Wreckage and Impact Information
The airplane was recovered from the ocean on December 18, 2013, and examined in Honolulu. The airframe was fragmented and battered consistent with wave action on a hard surface. The engine had separated from the airframe; the propeller remained attached with three blades intact, bent, and in the feather position. The engine was shipped to P&WC for further examination.
Survival Factors
The airplane had two flight crew seats and nine passenger seats. The pilot occupied the left seat; the right was empty. Passenger seats were numbered 1 through 9 from front to back on left and right sides. All seats except seat 9 (aft of the rear door) were occupied.
The pilot struck his head on the instrument panel during impact and was bleeding. He unstrapped, yelled for exit, grabbed seat cushions for flotation, and gave a life vest to a passenger who said his wife lacked one. He exited last through the rear door and instructed passengers to swim away due to sinking risk. Waves were estimated at 6 to 8 feet. The pilot weighed 240 pounds.
Passengers 1 and 2 (a married couple) sustained serious injuries; their daughter reported broken ribs and a gash for passenger 1, broken ribs and sternum for passenger 2. They received a briefing on the morning flight but not the accident flight. Passenger 1 weighed 200 pounds; passenger 2 weighed 175 pounds.
The fatally injured passenger (passenger 3) exited under her own power wearing an inflated life vest. Examination showed it was an infant vest with one punctured CO2 cartridge and one full, consistent with partial inflation. Passenger 3 weighed 220 pounds.
Passenger 4 reported no safety briefing before takeoff. He found a life vest in a seat pocket, put it on, and helped at the rear door. He saw passenger 3 inflate her vest and then enter the water. He stayed with her; she was breathing hard and fast, then stopped. He noted difficulty opening the vest pouch and that the vest was tight on his neck. He did not use the waist strap. His vest was an adult type; he weighed 175 pounds.
Passengers 5 and 6 (married couple) said the pilot assigned seats but gave no safety briefing. After impact, passenger 6 opened the rear door and jumped into the water without a vest; passenger 5 followed. Someone threw vests; passenger 6 grabbed two, inflated one without wearing it, and helped his wife put on and inflate a vest. She did not use the waist strap and reported the vest choked her. Both vests were adult type; passenger 5 weighed 210 pounds, passenger 6 weighed 200 pounds.
Passenger 7 reported easy egress. He helped an older couple open vest pouches, put on vests, and inflate one cartridge each. He swam to shore and later found he wore an infant vest, which felt small but worked. He weighed 160 pounds.
Passenger 8 reported no problems; his video showed he retrieved a vest from the seat pocket. He weighed 160 pounds.
Autopsy of the fatally injured passenger cited acute cardiac arrhythmia due to hyperventilation, with no significant traumatic injuries.
Review of 14 CFR 135.117 indicates that before each takeoff, passengers must be orally briefed on emergency exit location and operation, survival equipment, and ditching procedures for extended overwater operations.
Tests and Research
Engine examination at P&WC revealed external damage consistent with ocean rolling. All power turbine blades were fractured with overload signatures. Compressor turbine vane ring trailing edges were fractured; shroud segments had metal spray deposits and impact marks. Compressor turbine blades were fractured, leaving 1/3 to 2/3 of span; surfaces coated with white deposit. Metallographic examination of selected blades found no fatigue cracking; melting at tips was evident but no creep observed. One blade had an inclusion away from fracture, with no cracks.
Reduction gearbox housing was mostly dissolved by corrosion; internal components were intact. Accessory gearbox internal gears had white powdery deposit but were intact. Fuel heater was dented; thermal element nonfunctional. Fuel pump drive spline could not be turned; no evidence of cavitation. Propeller governor had corrosion and debris; driveshaft and levers restricted. Further details are in the Powerplants Group Chairman's Report.