Unalaska, AK, USA
N547LM
Beech 200
According to the pilot, when the airplane’s airspeed reached about 90 knots during the takeoff roll, he applied back pressure to the control yoke to initiate the takeoff and noted a brief positive rate of climb followed by a sinking sensation. The airspeed rapidly decayed, and the stall warning horn sounded. To correct for the decaying airspeed, he lowered the nose then pulled back on the airplane’s control yoke and leveled the wings just before impacting the ocean. The pilot stated there were no preaccident mechanical malfunctions or anomalies that would have precluded normal operation. Wind about the time of the accident was recorded as 110º downwind of the airplane at 15 knots gusting to 28 knots. The passengers recalled that the pilot’s preflight briefing mentioned the downwind takeoff but included no discussion of the potential effect of the wind conditions on the takeoff. The airplane’s estimated gross weight at the time of the accident was about 769.6 pounds over its approved maximum gross weight, and the airplane’s estimated center of gravity was about 8.24 inches beyond the approved aft limit at its maximum gross weight. It is likely that the pilot’s decision to takeoff downwind and operate the airplane over the maximum gross weight with an aft center of gravity led to the aerodynamic stall during takeoff and loss of control. Downwind takeoffs result in higher groundspeeds and increase takeoff distance. While excessive aircraft weight increases the takeoff distance and stability, and an aft center of gravity decreases controllability. Several instances of the operator’s noncompliance with its operational procedures and risk mitigations were discovered during the investigation, including two overweight flights, inaccurate and missing information on aircraft flight logs, and the accident pilot’s failure to complete a flight risk assessment for the accident flight. The operator had a safety management system (SMS) in place at the time of the accident that required active monitoring of its systems and processes to ensure compliance with internal and external requirements. However, the discrepancies noted with several flights, including the accident flight, indicate that the operator’s SMS program was inadequate to actively monitor, identify, and mitigate hazards and deficiencies.
HISTORY OF FLIGHT On January 16, 2020, about 0806 Alaska standard time, a Beech 200, Lifeguard N547LM, sustained substantial damage when it was involved in an accident near Unalaska, Alaska. The airline transport pilot was seriously injured, and the two passengers were uninjured. The airplane was operated as a Title 14 Code of Federal Regulations Part 135 air ambulance flight. At the time of the accident, dark night conditions prevailed. According to the pilot, after checking the weather on the automated weather observing system, he completed the before takeoff checks. The airplane was equipped with a cockpit voice recorder, which recorded an automated weather report for 0754. According to the passengers seated in the back of the airplane, the pilot conducted a preflight briefing that mentioned the downwind takeoff but included no discussion of the potential effect of the wind conditions on the takeoff. The pilot stated that he taxied for a runway 31 departure and initiated the takeoff roll. He said he recalled the wind conditions being reported as 100° at 9 knots. As the airplane accelerated down the runway, the airspeed was about 75 knots at midfield and increasing. When the airspeed reached about 90 knots, the pilot applied back pressure to the control yoke to initiate the takeoff and noted a brief positive rate of climb, followed by a sinking sensation. According to the passengers seated in the back, the initial takeoff run, and acceleration of the airplane did not appear unusual; however, the airplane seemed to remain on the runway longer than normal. The pilot stated that the airspeed rapidly decayed, and the stall warning horn sounded; the cockpit voice recorder recorded a tone consistent with a stall warning horn. To correct for the decaying airspeed, the pilot lowered the nose and immediately noticed the airplane’s illuminated lights reflecting off the surface of the water. One of the passengers reported that he felt the nose of the airplane lift from the surface of the runway before settling back down followed by another rotation and a substantial bump. The other passenger reported that he felt the nose of the airplane lift off the runway, followed by a substantial bump as if the airplane struck something at the end of the runway. The pilot pulled back on the airplane’s control yoke and leveled the wings just before the airplane impacted the ocean. After the airplane came to rest and began to fill with water, the three occupants exited the airplane through the over-the-wing emergency exit into a liferaft. The pilot stated there were no preaccident mechanical malfunctions or anomalies that would have precluded normal operation. Weight and Balance According to the last documented weight and balance information located for the airplane from September 21, 2018, the basic empty weight of the airplane was 8,478.5 lbs with a center of gravity of 187.44 inches. At the airplane’s maximum takeoff gross weight, 12,500 lbs, the center of gravity range was 185.0 inches to 196.4 inches. The airplane’s weight and balance at the time of the accident was estimated based on the weights of the pilot from his most current FAA medical examination (267 lbs) and passengers (260 lbs and 225 lbs), and the weight of the airplane’s equipment, medical equipment, and personal gear on board (484.3 lbs). The aircraft was fueled the day before the accident, and the fueler reported that he had filled both the main and auxiliary fuel tanks. The fuel onboard at the time of the accident was about 544 gallons (3,644.8 lbs). The gross weight of the airplane at the time of the accident with full fuel tanks was calculated at about 13,269.6 lbs, and the estimated center of gravity was 204.64 inches. The pilot stated that the typical standard fuel load for Dutch Harbor Airport (DUT), Unalaska, Alaska, was full main tanks and 45 gallons in each auxiliary tank for a total of about 450 gallons, which the pilot said he thought was on board the accident flight. Using the standard fuel load of 450 gallons (3,015 lbs) in place of the known quantity of 544 gallons of fuel in the weight and balance calculation for the accident flight results in a gross weight of about 12,640 lbs with a center of gravity of 214.84 inches. Two aircraft flight logs were recovered from the accident airplane. The top page contained a place for the pilot to input flight information that included weight and balance information; multiple carbon copies were available underneath the top page. However, only the original document contained the weight and balance information for the flight. Only a copy of the flight log for the accident flight was recovered; therefore, any weight and balance information computed by the pilot and recorded on the original document was not discovered. In addition, the flight log copy appeared to be missing other pieces of required information. On January 15, the day before the accident, the airplane was repositioned from Ted Stevens Anchorage International Airport (ANC), Anchorage, Alaska, to DUT. The gross weight for this flight was estimated at about 13,619.8 lbs, and the center of gravity was estimated as 192.67 inches. A flight log recovered for the repositioning flight indicated a loaded weight of 12,497 lbs and a center of gravity of 188.9 inches. The Pilot’s Handbook of Aeronautical Knowledge FAA-H-8083-25 states in part: Effects of Weight on Flight Performance A heavier gross weight will result in a longer takeoff run and shallower climb, and faster touchdown speed and longer landing roll. Effects of Weight on Stability and Controllability Although the distribution of weight has the most direct effect on this, an increase in the airplane’s gross weight may be expected to have an adverse effect on stability, regardless of location of the center of gravity. Effect of Load Distribution Generally, an airplane becomes less controllable, especially at slow flight speeds, as the center of gravity moves aft. Flight Risk Assessment According to Aero Air’s program manager, the operator used two flight risk assessments at the time of the accident. A pilot would fill out a simplified flight risk assessment if the flight met the criteria for the low-risk category and a full flight risk assessment for flights other than low risk. No flight risk assessment was completed for the accident flight. According to criteria used by the operator, a full flight risk assessment would have been required for the accident flight. According to the director of operations, flight risk assessments were reviewed or audited by the company’s administrator on-call group. Cockpit Voice Recorder The airplane was equipped with a Fairchild A-100S cockpit voice recorder (CVR) designed to record 30 minutes of digital audio, including channels for each flight crewmember, one channel for a cockpit observer, and a channel for the cockpit area microphone. The National Transportation Safety Board Vehicle Recorder Division successfully downloaded audio from the crash-survivable memory unit. Safety Management System (SMS) The operator had an SMS system in place at the time of the accident, which included a safety assurance component. Chapter 4 of the Aero Air, LLC Safety Management System Manual, Safety Assurance, stated in part: Safety assurance demands Aero Air actively monitor systems and processes to continuously identify new hazards, measure the effectiveness of aircraft operations and maintenance, and monitor risk controls that have been implemented in order to ensure compliance with internal and external requirements.
The pilot’s improper decision to takeoff downwind and to load the airplane beyond its allowable gross weight and center of gravity limits, which resulted in an aerodynamic stall and loss of control. Contributing to the accident was the inadequacy of the operator’s safety management system to actively monitor, identify, and mitigate hazards and deficiencies.
Source: NTSB Aviation Accident Database
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