Kahului, HI, USA
N5601C
Cessna 414A
The twin-engine medical transport airplane was on a positioning flight when the pilot reported a loss of power affecting one engine before impacting terrain 0.6 miles west of the approach end of the runway. The airplane was at 2,600 feet and in a shallow descent approximately 8 miles northwest of the airport when the pilot checked in with the tower and requested landing. Three and a half minutes later, the pilot reported that he had lost an engine and was in a right-hand turn. Radar data indicated that the airplane was 2 miles southwest of the airport at 1,200 feet msl. The radar track continued to depict the airplane in a descent and in a right-hand turn, approximately 1.9 miles west of the approach end of the runway. The altitude fluctuated between 400 and 600 feet, the track turned right again, and stabilized on an approximate 100-degree magnetic heading, which put the airplane on a left base for the runway. The track entered a third right-hand turn at 500 feet. The pilot's last transmission indicated that one engine was not producing power. The last radar return was 6 seconds later at 200 feet, in the direct vicinity of where the wreckage was located. Using the radar track data, the average ground speed calculations showed a steady decrease from 134 knots at the time of the pilot's initial report of a problem, to 76 knots immediately before the airplane impacted terrain. The documented minimum controlable airspeed (Vmc) for this airplane is 68 knots. The zero bank angle stall speed varied from 78 knots at a cruise configuration to 70 knots with the gear and flaps down. A sound spectrum study using recorded air traffic control communications concluded that one engine was operating at 2,630 rpm, and one engine was operating at 1,320 rpm. Propeller damage was consistent with the right engine operating at much higher power than the left engine at the time of impact, and both propellers were at or near the low pitch stops (not feathered). Examination and teardown of both engines did not reveal any evidence of mechanical malfunction. Investigators found that the landing gear was down and the flaps were fully deployed at impact. In this configuration, performance calculations showed that level flight was not possible with one engine inoperative, and that once the airspeed had decreased below minimum controllable airspeed (Vmc), the airplane could stall, roll in the direction of the inoperative engine, and enter an uncontrolled descent. The pilot had been trained and had demonstrated a satisfactory ability to operate the airplane in slow flight and single engine landings. However, flight at minimum controllable airspeed with one engine inoperative was not practiced during training. The operator's training manual stated that during single engine training an objective was to ensure the pilot reduced drag; however, there was no procedure to accomplish this objective, and the ground training syllabus did not specifically address engine out airplane configuration performance as a dedicated topic of instruction. The operator's emergency procedures checklist and manufacturer's information manual clearly addressed the performance penalties of configuring the airplane with an inoperative engine, propeller unfeathered, the landing gear down, and/or the flaps deployed. The engine failure during flight procedure checklist and the engine inoperative go-around checklist, if followed, configure the airplane for level single engine flight by feathering the propeller, raising the flaps, and retracting the landing gear.
1.1 HISTORY OF FLIGHT On March 8, 2006, at 1913 Hawaii standard time, a Cessna 414A, N5601C, collided with terrain during an uncontrolled descent following a loss of engine power approximately 1 mile west of the Kahului Airport, Kahului, Maui, Hawaii. The airplane was operated by Hawaii Air Ambulance as a positioning flight under the provisions of 14 CFR Part 91. The airline transport pilot and two flight medical attendants were fatally injured. The airplane was destroyed by post impact fire. Visual meteorological conditions prevailed, and an instrument flight plan had been filed. The flight originated at Honolulu International Airport, Honolulu, Hawaii, at 1830. Hawaii Air Ambulance (HAA) reported to the Safety Board investigator that the airplane was to fly from Honolulu Airport to Kahului Airport to pickup a patient for transport. Witnesses reported that they observed the multiengine airplane maneuvering very low, between 100 and 300 feet, about 1 mile west of the Kahului Airport. They noted the wings wobbled at times, and the airplane rolled up to 60 degrees angle of bank other times. All witnesses said that they heard engine noises that they associated with an engine or engines operating at high power. They saw the airplane's landing and position lights on. Witnesses said that just prior to impact, the airplane's wings wobbled, and then the airplane dropped straight down into an automobile dealership and exploded. Honolulu Center (Honolulu Control Facility radar) data depicted the accident airplane departing Honolulu Airport at 1835:11, and turning to an easterly course at an altitude of approximately 7,000 feet mean sea level (msl). The radar track paralleled the north shore of Molokai, then turned southeast after passing Kalaupapa Airport on a direct course towards Kahului Airport. During this time the track also entered a shallow, approximately 500 fpm, descent. At 1908:02, Kahului tower gave N5601C a landing clearance for runway 02. The track crossed the Kahului Harbor at 1911:06, at an altitude of 1,200 feet msl, and an average ground speed of 134 knots. At 1911:33, the pilot reported to Kahului tower that he had lost an engine, was in a right-hand turn, and requested assistance. The radar track continued to depict the airplane in a descent and in a right-hand turn over the area between Highway 36 (Hana Highway) and Highway 311, approximately 1.9 miles west of the approach end of runway 02. The average ground speed during this portion of the track was 110 knots. The altitude fluctuated between 400 and 600 feet, the track turned right over the Kanaha Pond, and stabilized on an approximate 100-degree magnetic heading, which put the airplane on a left base for runway 02. The average ground speed was 86 knots. The track entered a third right-hand turn over the Hana Highway (Hwy 36) at 500 feet, and the average ground speed had decreased to 76 knots. At 1912:54, the pilot's last transmission was "Zero one Charlie, we lost an engine." The last radar return was at 1913:00, 200 feet over the Hana Highway. The wreckage was located in the BMW automobile dealership and was completely destroyed by a post impact fire. Ten automobiles were also destroyed. 1.5 PERSONNEL INFORMATION A review of Federal Aviation Administration (FAA) records revealed that the pilot held an airline transport pilot (ATP) and certified flight instructor (CFI) certificates with ratings for airplane multiengine land, airplane single engine land, and airplane instrument. The pilot held a first-class medical certificate issued on October 31, 2005. A review of the pilot's logbook and HAA training records indicated that he had accumulated approximately 3,141.6 hours of total fight time, and 1,518.6 hours of multiengine flight time. He had logged 174.1 hours in the last 90 days and 48.7 in the last 30 days, all of which were in the Cessna 414A. The chief pilot for HAA stated that the accident pilot had a very good feel for the airplane, had no issues handling the aircraft, and was an above average pilot by company standards. He said that the accident pilot proceeded through the initial training in the Cessna 414A in 10.2 hours, where most new hires average 15 hours to complete the training. The accident pilot completed his HAA initial flight training on April 29, 2005. The chief pilot performed the accident pilot's 6-month line check (FAR Part 135.297) on November 25, 2005. The chief pilot graded the pilot as 'unsat' for a procedural error during a missed approach from an ILS. He performed some remedial instruction with the pilot and then completed the line check in the same flight. He noted that the accident pilot performed very well during the single engine portion of the line check. On July 1, 2005, the pilot was involved in an airplane accident at Honolulu Airport, in which he was acting as CFI, and was not on duty with HAA. The accident involved a multiengine airplane, executing a single engine landing with the landing gear not fully down and locked, followed by an attempted go-around executed during the landing flare. The National Transportation Safety Board determined that the CFI did not follow the procedures for manually lowering the landing gear, did not utilize the emergency procedures to blow down the landing gear, and failed to maintain minimum controllable airspeed (Vmc) during the attempted go-around. A review of the pilot's 72-hour history prior to the accident revealed that he had family visiting him in Honolulu, and he kept his normal sleep periods. On the day of the accident he had a late breakfast and went surfing before reporting to work. 1.6 AIRCRAFT INFORMATION The airplane was a Cessna 414A, serial number 0113. It was configured for medical transport of a single patient on a gurney. The crew consisted of a single pilot and two flight medical attendants. Hawaii Air Ambulance acquired the airplane in July 2004. A review of the airplane's maintenance records revealed that it had 8,734.7 hours total time. The airplane had two Teledyne Continental TSIO-520 turbocharged engines, and two McCaulley 76.5-inch, 3 bladed propellers. The left engine time since maintenance overhaul (TSMOH) was 1,053.8 hours. The left propeller TSMOH was 1,053.8 hours. The right engine TSMOH was 985.1 hours, and the right propeller TSMOH was 331.4 hours. Weight and balance records for the accident flight document that the airplane departed Honolulu at a total gross takeoff weight of 6,597 pounds, and was calculated to arrive at Maui with a landing weight of 6,447 pounds. The Cessna Model 414A Information Manual states that the maximum takeoff weight is 6,750 pounds, the best single engine rate of climb speed (Vy) is 108 knots, the minimum controllable airspeed (Vmca) is 79 knots, and the stall speed at max gross weight, zero degrees flaps, and zero angle of bank is 82 knots. The stall speed at max gross weight, with 45 degrees flaps and zero angle of bank, is 71 knots. The airplane had been equipped with Micro Aerodynamics, Inc., micro vortex generators (STC number SA5131NM) installed on June 16, 1994. The applied STC increased the maximum takeoff weight to 7,100 pounds, decreased Vmca to 68 knots, decreased the stall speed to 78 knots in the cruise configuration (zero degrees of flaps and zero angle of bank), and decreased the stall speed to 70 knots in the landing configuration (gear down, flaps 45 degrees). Maintenance was performed on a progressive phase inspection program. The last phase inspection prior to the accident was the phase-4 inspection completed on March 3, 2006. The phase-4 inspection involved detailed maintenance on the right engine, right propeller, and right wing, while routine maintenance was performed on the left engine, left propeller, left wing, and all three landing gear mounts. The maintenance performed on the left engine involved changing the oil and spark plugs. All applicable Airworthiness Directives (ADs) had been complied with except AD-2005-20-25, which involved the avionics bus circuit breaker switches. The functional check of the left and right wing fuel inlet float valve (AD 95-09-13) was documented as performed on February 2, 2006. The previous phase inspection, phase-3, was completed on February 15, 2006, and involved a detailed inspection of the left engine, left propeller, and landing gear, with routine maintenance to the right engine, right propeller, nose section, cabin, and cockpit. Maintenance records for 30 days prior to the accident revealed discrepancies with the course deviation indicator (CDI), weather radar, air conditioner, left and right brakes, aft seat headphone jack, radio hand microphone, and numerous autopilot problems. These discrepancies were all documented as being resolved by the maintenance personnel. The airplane flew 63 times during the previous 30 days. 1.12 WRECKAGE AND IMPACT INFORMATION The wreckage was located in a BMW automobile dealership parking lot at 410 Koloa Street, Kahului, approximately 0.6 miles west of the approach end of runway 02. The global positioning system coordinates (GPS) were 20 degrees 53.211 minutes north latitude by 156 degrees 27.263 minutes west longitude, at an elevation of 10 feet. The wreckage was confined to the compact impact area, roughly the same dimensions of the airplane surrounded by parked cars. The wreckage was on a bearing of 055 degrees magnetic measured from tail to nose. Inspectors from the FAA, and technical representatives from the Cessna Aircraft Company, Teledyne Continental Motors (TCM), and Hawaii Air Ambulance, examined the wreckage under the supervision of the Safety Board investigator-in-charge (IIC). The airplane wreckage had been exposed to extreme thermal energy resulting in complete destruction of the wings, tail, and fuselage. The center wing box area, cockpit, and nose section of the plane was at the center of the wreckage in an inverted configuration. Ash and melted metal outlined the remaining area of the airplane. An 8-inch circular indentation in the asphalt was identified with a ball bearing race and propeller snap rings embedded into the surface. Five feet away, two slashes were documented that measured roughly 13 and 14 inches in length, 15 inches apart, angled about 20 degrees to the horizon, in the back end of an automobile. Above the automobile was a light pole that was missing one of its two light boxes. On the ground below the light pole was the light box with a semicircular deformation across its entirety. A light pole on the other side of the wreckage had a deformed light box, and the right fiber glass composite wing tip was located below it. The flight control surfaces, associated bell cranks, and flaps were destroyed by fire; however, the steel control cables remained intact. The flight control cables were found lying in their appropriate positions along the left and right wing areas, and the tail. The aileron control cables were traced from the wing to the cockpit control yoke. The elevator cables were traced from the tail area to the control; one side of the cable was separated with the ends broom strawed. The rudder cables were traced from the cockpit rudder bar to the tail. The elevator, aileron, and rudder trim cables were traced from the cockpit to their respective attach locations. According to the airframe manufacturer's representative, an accurate reading of the rudder trim measurement could not be obtained. The elevator trim was measured to be 10 degrees tab up (nose down trim), and the aileron trim was measured as 5 degrees tab up (left wing down). The Cessna representative indicated that the landing gear hydraulic actuators were extended, which was consistent with the gear down position. The flap drive chain was observed to run full out, which the manufacturer's representative said corresponded to the flaps full down position. The left and right fuel valves were located, and it was determined that both were in the closed position. The airframe manufacturer's representative stated that the fuel valves are operated from the cockpit fuel selector using a system of cables, and that the cables would typically pull the valves closed during the crash sequence. Both TCM TSIO-520 engines were present in their appropriate locations, and semi attached to their mounts. The propellers and hubs separated at the crankshaft flanges on both engines. The left engine was inverted on the asphalt and had been exposed to extreme thermal energy. The right engine was upright on the asphalt and the throttle plate was in the full open position. The throttle, mixture, and propeller control cables were traced from each engine to the cockpit and observed attached to the control lever quadrant. The left engine turbocharger was found seized, with compressor impeller damage. The waste gate was closed. The right engine turbocharger could be rotated by hand, compressor impeller damage was evident, and the waste gate was open. The engines were crated and shipped to TCM bonded storage facility for further examination. The nose of the airplane appeared to be crushed aft into the cockpit. Numerous rolls of rubber tire tread ballast was observed in the nose area. The cockpit was completely destroyed. All levers on the engine control quadrant were in their forward positions. Most cockpit instrumentation and instrument panel switch positions were destroyed by thermal exposure. The altimeter was observed as set to 29.99 inHg. The positions of the victims in the wreckage were consistent with the following aircrew seat positions. The pilot was located in the left side of the cockpit; the male medical attendant was located in the right side of the cockpit, and the female medical attendant was located behind the cockpit right seat. 1.13 MEDICAL AND PATHOLOGICAL INFORMATION The Maui Memorial Medical Center completed autopsies on all three members of the aircrew. The FAA Forensic Toxicology Research Team at the Civil Aviation Medical Institute (CAMI) performed toxicological testing of specimens collected from the aircrew during their respective autopsies. The results of the specimens were negative for carbon monoxide, cyanide, and listed drugs. The pilot tested positive for ethanol, n-propanol, and butanol; 16 mg/ml ethanol in blood, 59 mg/ml ethanol in muscle, 41 mg/ml ethanol in kidney, 1 mg/dl n-propanol in blood, 3 mg/dl n-propanol in muscle, 6 mg/dl n-propanol in kidney, and 1 mg/dl n-butanol in blood. All levels of ethanol, n-propanol, and butanol were associated with postmortem ethanol production. The male medical attendant tested positive for ethanol, 46 ml/dl detected in blood. The ethanol was associated with postmortem ethanol production. 1.14 FIRE The aircraft wreckage experienced a severe post impact fire that completely consumed the majority of the airframe. Fire Station 742 received notification of the accident from the airport tower at 1913. Rescue units 1,3, and 5 were on scene at 1918. The fire was reported as under control at 1944. 1.16 TESTS & RESEARCH 1.16.1 Audio Recording Sound Spectrum Study A copy of air traffic control transmissions recorded at the Kahului Airport tower was sent to the audio laboratory at the Safety Board on March 28, 2006. A sound spectrum study was completed to identify any background sound signatures that could be associated with the aircraft. Because voice signatures tend to dominate the audio, obscuring aircraft sound signatures, the focus of the sound spectrum study was on the non-voice sections of the pilot's transmissions, such as pauses between words or after speaking, but prior to the release of the microphone key. In particular, a sound spectrum review was completed on the following radio transmissions. Radio transmission 1 - "final, cleared to land two, zero one Charlie" Radio transmission 2 - "Maui, I was in a right turn we lost an engine, ah, we need assistance." Radio transmission 3 - "Maui tower zero one Charlie we lost an engine...***... zero one Charlie we lost an engine." Each transmission contained the following audio signatures. Given that the 3-bladed propellers produced the signatures, the audio signatures can be se
The failure of the pilot to execute the published emergency procedures pertaining to configuring the airplane for single engine flight, which would have allowed him to maintain minimum controllable airspeed (Vmc) and level flight. The pilot's failure to maintain minimum controllable airspeed (Vmc) led to a stall and subsequent Vmc roll at a low altitude. Contributing to the accident was the operator's inadequate pilot training in the single engine flight regime, and the loss of power from the left engine for undetermined reasons.
Source: NTSB Aviation Accident Database
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