NTSB Factual Report

HISTORY OF THE FLIGHT

On July 3, 1997, about 1730 Alaska daylight time, a wheel equipped Piper PA-32 airplane, N15199, ditched in the ocean about 1 1/2 miles southwest of Skagway, Alaska. The airplane was being operated as a visual flight rules (VFR) sightseeing flight under Title 14 CFR Part 135 when the accident occurred. The airplane, registered to and operated by Haines Airways Inc., Haines, Alaska, sank after ditching. The certificated commercial pilot was not injured. One passenger sustained minor injuries. Two passengers received fatal injuries. Two additional passengers were not located, and are presumed to have received fatal injuries. Visual meteorological conditions prevailed. VFR company flight following procedures were in effect. The flight originated at the Haines Airport, at 1640.

The flight was one of several airplanes utilized to provide sightseeing flights for cruise liner passengers. The passenger's cruise ship was docked in Skagway, and the accident flight was the second portion of an eagle viewing/glacier tour from Skagway to Haines, and return. Following the departure from Haines, the flight proceeded to overfly several glaciers, and then flew north into the Taiya Inlet. The terrain in the inlet is comprised of steep mountains that descend to the water with infrequent areas of small beach. Voluntary traffic flow procedures for airplanes operating into, and out of Skagway, have been established by agreement with the Federal Aviation Administration (FAA), and operators in the area. In-bound airplanes to Skagway fly northbound along the west shoreline of the Taiya Inlet. Position reports are usually made by arriving pilots at Taiya Point, Long Falls, and Burrow Creek.

The pilot reported she was proceeding northbound along the west side of the Taiya Inlet about 1,500 feet mean sea level. She was slowly descending for landing with the airplane positioned between 1/4 to 1/2 mile from the shore. As the flight was approaching Burro Creek, a VFR reporting point that is about 2 miles southwest of Skagway, the engine began to lose fuel pressure, and then stopped. At that time, the airplane was about 1,200 feet msl. Emergency procedures failed to restore engine power.

The pilot transmitted several radio calls for assistance, stating among other calls, "I need help" several times. Other company pilots heard the radio calls from the accident airplane, and attempted to offer suggestions over the radio. The pilot initially made a right turn in a northeast direction, toward runway 01 at Skagway. The pilot determined the airplane lacked sufficient altitude to glide across the inlet to the Skagway Airport, and made a left turn toward the west shore of the Taiya Inlet. The pilot selected full flaps, and ditched the airplane about 100 feet from the west shoreline of the inlet.

Following water contact, the pilot indicated the front seat and middle seat occupants exited the airplane through the right front door. The rear seat occupants exited through the left rear door. All occupants successfully evacuated the airplane into the water. The water temperature was estimated at 39 degrees F. Following water impact, the pilot of the accident airplane was heard over the radio to yell, "get out" several times.

A tour helicopter based in Skagway was following the accident airplane into Skagway, and was about 1 mile behind the airplane. The pilot of the helicopter observed the airplane in the water and orbited over the scene. The helicopter pilot reported observing five persons near the sinking airplane. The occupants of the helicopter threw several life vests into the water in an attempt to aid the survivors. The helicopter pilot requested additional help, and a second helicopter responded to the scene within 10 minutes. The two survivors were pulled from the water by the crew of the second helicopter, and air-lifted to Skagway.

The accident occurred during the hours of daylight at latitude 59 degrees, 26.98 minutes north, and longitude 135 degrees, 21.76 minutes west.

CREW INFORMATION

The pilot holds a commercial pilot certificate with airplane single-engine land, single-engine sea, multiengine land, and instrument airplane ratings. In addition, the pilot holds a flight instructor certificate with airplane single-engine, and instrument airplane ratings. The most recent first-class medical certificate was issued to the pilot on September 10, 1996, and contained no limitations.

The pilot completed her basic indoctrination training on April 15, 1997. She received her Part 135 pilot check-flight on April 21, 1997, and her route check flights on April 24, 1997.

According to the operator, the pilot's total aeronautical experience consists of about 1,815 hours, of which 200 hours were accrued in the accident airplane make and model. In the preceding 90 and 30 days prior to the accident, the pilot accrued a total of 189 and 106 hours respectively.

A review of the pilot's flight and duty records revealed that on June 30, 1997, the pilot worked from 0500 to 1430, and accrued 3.17 flight hours. On July 1 and July 2, 1997, the pilot worked from 0500 to 1830. The flight hours accrued on those days were not noted. The pilot began work at 0500 on the day of the accident.

AIRCRAFT INFORMATION

The airplane had accumulated a total time in service of 4,688.9 hours. Examination of the maintenance records revealed the most recent annual inspection was accomplished on October 14, 1996, 747.8 hours before the accident. In addition, a 100-hour inspection was completed on June 26, 1997, 47.5 hours before the accident.

The airplane was equipped with a Lycoming, IO-540-K1A5, engine. The engine was purchased from West Star Aviation Inc., Grand Junction, Colorado on September 25, 1996, as an exchanged, "0" time engine. West Star Aviation certified the engine as a: "Gold Star zero time equivalent engine per Lycoming manual 60294-7-4. Engine and accessories were remanufactured to factory new tolerances." The previous total time on the engine was 3,742.2 hours.

According to West Star personnel, the engine crankcase was cracked adjacent to the number 4 cylinder. The crankcase was sent to Div Co, Inc., Tulsa, Oklahoma, for welding and machining. Div Co personnel reported the crankcase was repaired on September 5, 1996. The repair included machining of the case-half mating surfaces, and welding and reboring of the magneto bearing bore holes, located at the aft end of the crankcase.

Since the engine was installed in the accident airplane on October 14, 1996, the engine had accrued 747.8 hours. The engine annual and 100 hour inspections, coincided with the airframe inspections.

The engine is equipped with Slick magnetos, part number 6351 for the left magneto, and part number 6350 for the right. The left magneto is equipped with an impulse coupling, part number M3333. The magnetos are subject to a recurring 500 hour inspection. That inspection was conducted by the operator on May 16, 1997, at 500.7 hours of service.

During normal operation, the engine accessory gears are turned either by the starter (during engine start), or by normal engine operation. When viewed from the aft end of the engine, looking forward, the crankshaft gear rotates clockwise. The crankshaft gear drives two intermediate idler gears in a counterclockwise direction. The idler gears drive the left and right engine magneto drive gears clockwise. The magneto drive gear mates to a rotating bearing installed in a bearing bore hole. The bearing bore is drilled into the aft end of the engine crankcase.

An impulse coupling is utilized to delay magneto spark during engine starting until the engine pistons have reached top dead center. The coupling consists of a hub assembly mounted on the magneto shaft. The hub assembly is comprised of a heel plate, on which two impulse pawls are attached by rivets. The rivets serve as an axle for the pawl, and are welded to the bearing plate. The rivet is used to secure the pawl plate assembly together by compressing the pawl plate, and the bearing plate together.

The impulse pawls pivot on the rivets during starting to engage a stop pin located on the magneto frame. When stationary, two thin wire impulse pawl retracting springs, installed between the impulse pawls and the pawl plate, serve to position the latching end of each pawl outward toward the stop pin during engine start. A coil spring is installed between the impulse coupling and the impulse shell. The shell covers the spring and hub assembly. The shell has two drive lugs on its outer surface that mate to the magneto drive gear. Two rubber cushions are installed around the impulse shell lugs, between the drive gear edge and the impulse shell drive lugs. The shell also has two impulse trip lugs located on the outer skirt of the shell that releases the impulse pawls as the shell rotates past the stop pin.

During engine start, usually below about 200 RPM, the impulse coupling pawls rotate outward. The latching end of the pawl engages the stop pin, which momentarily holds the magneto shaft from turning. As the magneto shaft is being held stationary, the impulse shell continues to be turned by the magneto drive gear, winding up the impulse coupling spring. As the impulse coupling shell rotates, its trip lugs contact the outer edge of the stationary impulse coupling pawl, and the pawl is disengaged from the stop pin. When the pawl is released, the energy stored in the coupling spring is released, briskly rotating the magneto rotor shaft. This momentary engagement/disengagement cycle occurs during every engine start sequence. Above about 350 RPM, centrifugal force acts on the counterweighted impulse coupling pawls to cause them to retract away from the stop pin.

The pilot and surviving passenger indicated the airplane engine was hard to start when the flight initially departed Skagway. The engine start required between 5 to 7 minutes. The engine start in Haines, on the accident flight, was uneventful.

The airplane's front and middle row of seats, were equipped with a pouch installed on the aft facing side of the upright, seat-back portion of each seat. The pilot's seat pouch, equipped with a zipper for closure, was positioned about 2/3 the way up the back of the seat. The passenger seat pouches, equipped with an elastic closure, were positioned about mid-height on the seat backs. Each seat pouch contained an airplane briefing card. The pouch also contained an inflatable life vest that is encased in plastic wrap. The seat assemblies had acrylic/sheep-skin type seat covers installed that slipped over the top of the seat-back, and also over the bottom cushion of the seat. The aft, bottom edge of the seat back portion of each seat cover, as installed, slipped down over the opening of the seat back pouches. The life vests for the front seat occupants were stored in pouches located at the lower portion of each side of the cockpit, below the instrument panel, and forward of the seats. The airplane's seat cushions are not designed for, nor are they required to be, a floatation device.

The briefing card contained in the airplane was produced by the Piper Aircraft Corporation for PA-32 and PA-34 series airplanes. It is designed as a supplement to the pilot's passenger briefing. The card contains text, and visual descriptions about adjusting the seats, a no-smoking caution, the use of seat belts, the use of oxygen, the operation of the cabin doors, and the use of the doors as emergency exits.

METEOROLOGICAL INFORMATION

The closest official weather observation station is Skagway, which is located 1.5 nautical miles northeast of the accident site. On July 3, 1997, at 1653, an automated aviation weather observation system, aviation routine weather report (METAR) was reporting, in part: Wind, 100 degrees (true) at 14 knots, wind varies between 080 and 220 degrees; visibility, 10 statute miles; clouds, 5,500 feet overcast; temperature, 65 degrees F; dew point, 52 degrees F; altimeter, 30.10 inHg.

COMMUNICATIONS

During the emergency, the pilot transmitted a radio call for help on the common traffic control frequency (CTAF) of 122.9 MHz. CTAF communications are not recorded in the Skagway area.

AERODROME AND GROUND FACILITIES

The Skagway airport is equipped with a single hard-surfaced runway on a 010 to 190 degree magnetic orientation. Runway 01 is 3,750 feet long by 75 feet wide.

WRECKAGE AND IMPACT INFORMATION

The airplane was ditched and sank, about 100 feet from an area of near vertical rocks. The wreckage was located by recovery divers at a depth of about 153 feet. The wreckage was recovered in the presence of the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on the night of July 9, 1997, by hoisting the airplane vertically out of the water by a cable attached to the propeller assembly. The wreckage was examined at Skagway, Alaska, on July 10, 1997, by all parties to the investigation, except the representative from Unison Industries.

All of the airplane's major components were found at the main wreckage area. The right wing exhibited upward and aft crushing on the underside of the leading edge, about 12 inches outboard from the wing root. The underside of the wing exhibited upward crushing in the area of the inboard fuel cap. The right main landing gear strut housing was bent aft about 45 degrees. The upper end of the strut housing was displaced upward through the upper surface of the wing. The interior strut sleeve and the right main wheel were missing.

The left wing was separated, torn and crushed in an aft direction, about 2 feet outboard from the wing root. The vertical face of the forward spar web exhibited a 90 degree twist and separation, with the bottom edge of the spar rolled forward, and the upper edge of the spar rolled aft. The wing exhibited upward bending about midspan, and upward and inward crushing to the underside of the wing at the point of separation. During the recovery of the airplane, the left wing twisted 180 degrees with the left main landing gear oriented upward.

The right stabilator exhibited minor wrinkling, and slight downward crushing of the upper surface. The left stabilator displayed minor damage to the outboard end of the fairing.

The left rear door of the airplane was unlatched. The upper door latch was unlocked.

The flight control surfaces remained connected to their respective attach points, and flight control system cable continuity was established throughout the airplane.

The manual flaps were found retracted. The elevator trim tab actuator was found extended three threads. According to the airplane manufacturer, the extended trim tab actuator threads do not correspond to an exact degree setting. Known points of measurement on the accident airplane make and model are as follows: zero threads extended equates to 5 degree tab up, (nose down) setting. Five threads extended equates to a neutral, or zero tab setting.

The nose gear assembly remained attached to the airplane, but was folded aft and upward against the bottom of the fuselage.

The propeller assembly remained connected to the engine crankshaft, and both blades were loose in the hub. One propeller blade exhibited minor aft bending about midspan. The second blade exhibited about 45 degrees of aft bending about midspan, and very slight torsional twisting.

The crankshaft could be rotated by the propeller. Hand rotation of the crankshaft did not produce any accessory gear or valve train movement.

The right magneto did not exhibit any damage, and was free to rotate by hand. The left magneto exhibited the presence of metal slivers and shavings around the magneto flange. The impulse coupling shell was cracked, and unable to be rotated by hand. The magneto pawls were observed extending beyond the impulse coupling shell. The left magneto accessory drive gear exhibited a broken gear tooth.

The electric engine boost pump operated when electrical power was attached to the pump.

Seat number 2B was found loose from its seat track attachment. No damage was observed to the seat latching mechanism.

Search personnel recovered f

NTSB Probable Cause

jamming/failure of the left magneto impulse coupling, which stopped rotation of the magneto gear, and resulted in subsequent shearing of the accessory intermediate idler gear. Factors relating to the accident were: the lack of suitable terrain for a forced landing, which necessitated ditching of the aircraft; the passenger's lack of awareness concerning access to life vests, due to the pilot's inadequate briefing and the seat covers being installed over pouches that held the life vests; insufficient company standards/procedures regarding access to life vests.