De Havilland DHC-3 Otter

Yakutat Coastal Airlines

The single engine airplane departed Yakutat on an on-demand flight to Dry Bay, a remote airstrip located about 30 miles southeast of the Southeast Alaska community of Yakutat. On final approach, the aircraft crashed in a wooded area located short of runway. All four occupants were injured, three critically.

Blue Water Aviation - Manitoba Air Charter Services

At approximately 0745 Central Daylight Time on 26 October 2019, the Blue Water Aviation float-equipped deHavillandDHC-3 Otteraircraft (registration C-GBTU, serial number 209) departed Bissett Water Aerodrome, Manitoba, with the pilot, 2 passengers, and approximately 800 pounds of freight on board. The destination was Little Grand Rapids, Manitoba, on the eastern shore of Family Lake. At approximately 0845, while on approach to Family Lake, the aircraft’s right wing separated from the fuselage. The aircraft then entered a nose-down attitudeand struck the water surface of the lake. The pilot and the 2 passengers were fatally injured. The aircraft was destroyed by impact forces. The emergency locator transmitter activated momentarily.

Taquan Air

On May 13, 2019, about 1221 Alaska daylight time, a float-equipped de Havilland DHC-2 (Beaver) airplane, N952DB, and a float-equipped de Havilland DHC-3 (Otter) airplane, N959PA, collided in midair about 8 miles northeast of Ketchikan, Alaska. The DHC-2 pilot and four passengers sustained fatal injuries. The DHC-3 pilot sustained minor injuries, nine passengers sustained serious injuries, and one passenger sustained fatal injuries. The DHC-2 was destroyed, and the DHC-3 sustained substantial damage. The DHC-2 was registered to and operated by Mountain Air Service LLC, Ketchikan, Alaska, under the provisions of Title 14 Code of Federal Regulations (CFR) Part 135 as an on-demand sightseeing flight. The DHC-3 was registered to Pantechnicon Aviation LTD, Minden, Nevada, and operated by Venture Travel, LLC, dba Taquan Air, Ketchikan, Alaska, under the provisions of Part 135 as an on-demand sightseeing flight. Visual meteorological conditions prevailed in the area at the time of the accident. According to information provided by the operators, both airplanes had been conducting sightseeing flights to the Misty Fjords National Monument area. They were both converging on a scenic waterfall in the Mahoney Lakes area on Revillagigedo Island before returning to the Ketchikan Harbor Seaplane Base (5KE), Ketchikan, Alaska, when the accident occurred. According to recorded avionics data recovered from the DHC-3, it departed from an inlet (Rudyerd Bay) in the Misty Fjords National Monument area about 1203 and followed the inlet westward toward Point Eva and Manzanita Island. At 1209, at an altitude between 1,900 and 2,200 ft, the DHC-3 crossed the Behm Canal then turned to the southwest about 1212 in the vicinity of Lake Grace. Automatic dependent surveillance-broadcast (ADS-B) tracking data for both airplanes, which were provided by the Federal Aviation Administration (FAA), began at 1213:08 for the DHC-3, and at 1213:55 for the DHC-2. At 1217:15, the DHC-3 was about level at 4,000 ft mean sea level (msl) over Carroll Inlet on a track of 225°. The DHC-2 was 4.2 nautical miles (nm) south of the DHC-3, climbing through 2,800 ft, on a track of 255°. The DHC-3 pilot stated that, about this time, he checked his traffic display and “there were two groups of blue triangles, but not on my line. They were to the left of where I was going.” He stated that he did not observe the DHC-2 on his traffic display before the collision. The ADS-B data indicated that, about 1219, the DHC-3 started a descent from 4,000 ft, and the DHC-2 was climbing from 3,175 ft. During the next 1 minute 21 seconds, the DHC-3 continued to descend on a track between 224° and 237°, and the DHC-2 leveled out at 3,350 ft on a track of about 255°. Between 1220:21 and 1221:14, the DHC-3 made a shallow left turn to a track of 210°, then a shallow right turn back to a track of 226°. The airplanes collided at 1221:14 at an altitude of 3,350 ft, 7.4 nm northeast of 5KE. The ADS-B data for both airplanes end about the time of the collision. The DHC-2 was fractured into multiple pieces and impacted the water and terrain northeast of Mahoney Lake. Recorded avionics data for the DHC-3 indicate that at 1221:14, the DHC-3 experienced a brief upset in vertical load factor and soon after entered a right bank, reaching an attitude about 50° right wing down at 1221:19 and 27° nose down at 1221:22. The DHC-3 began descending and completed a 180° turn before impacting George Inlet at 1222:15 along a northeast track.

Taquan Air

The airline transport pilot was conducting a commercial visual flight rules (VFR) flight transporting 10 passengers from a remote fishing lodge. According to the pilot, while in level cruise flight about 1,100 ft mean sea level (msl) and as the flight progressed into a mountain pass, visibility decreased rapidly. In an attempt to turn around and return to VFR conditions, the pilot initiated a climbing right turn. Before completing the 180° right turn, he saw what he believed to be a body of water and became momentarily disoriented, so he leveled the wings. Shortly thereafter, he realized that the airplane was approaching an area of snow-covered mountainous terrain, so he applied full power and initiated a steep climb; the airspeed decayed, and the airplane collided with an area of rocky, rising terrain, which resulted in substantial damage to the wings and fuselage. The pilot reported no mechanical malfunctions or anomalies that would have precluded normal operation, and the examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The weather forecast at the accident time included scattered clouds at 2,500 ft msl, overcast clouds at 5,000 ft msl with cloud tops to 14,000 ft and clouds layered above that to flight level 250, and isolated broken clouds at 2,500 ft with light rain. AIRMET advisory SIERRA for "mountains obscured in clouds/precipitation" was valid at the time of the accident. Conditions were expected to deteriorate. Passenger interviews revealed that through the course of the flight, the airplane was operating in marginal visual meteorological conditions and occasional instrument meteorological conditions (IMC) with areas of precipitation, reduced visibility, obscuration, and, at times, little to no forward visibility. Thus, based on weather reports and forecasts, and the pilot's and passengers' statements, it is likely that the flight encountered IMC as it approached mountainous terrain and that the pilot then lost situational awareness. The airplane was equipped with a terrain awareness and warning system (TAWS); however, the alerts were inhibited at the time of the accident. Although the TAWS was required to be installed per Federal Aviation Administration (FAA) regulations, there is no requirement for it to be used. All company pilots interviewed stated that the TAWS inhibit switch remained in the inhibit position unless a controlled flight into terrain (CFIT) escape maneuver was being accomplished. However, the check airman who last administered the accident pilot's competency check stated that the TAWS inhibit switch was never moved, even during a CFIT escape maneuver. The unwritten company policy to leave the TAWS in the inhibit mode and the failure of the pilot to move the TAWS out of the inhibit mode when weather conditions began to deteriorate were inconsistent with the goal of providing the highest level of safety. However, if the pilot had been using TAWS, due to the fact that he was operating at a lower altitude and thus would have likely received numerous nuisance alerts, the investigation could not determine the extent to which TAWS would have impacted the pilot's actions. At the time of the accident, the director of operations (DO) for the company resided in another city and served as DO for another air carrier as well. He traveled to the company's main base of operation about once per month but was available via telephone. According to the chief pilot, he had assumed a large percentage of the DO's duties. The president of the company said that the chief pilot had taken over "officer of the deck" and "we're just basically using him [the DO] for his recordkeeping." The FAA was aware that the company's DO was also DO for another commuter operation. FAA Flight Standards District Office management and principal operations inspectors allowed him to continue to hold those positions, although it was contrary to the guidance provided in FAA Order 8900.1. The company's General Operations Manual (GOM) only listed the DO, the chief pilot, and the president by name as having the authority to exercise operational control. However, numerous company personnel stated that operational control could be and was routinely delegated to senior pilots. The GOM stated that the DO "routinely" delegated the duty of operational control to flight coordinators, but the flight coordinator on duty at the time of the accident stated that she did not have operational control. In addition, the investigation revealed numerous inadequate and missing operational control procedures and processes in company manuals and operations specifications. Based on the FAA's inappropriate approval of the DO, the insufficient company onsite management, the inadequate operational control procedures, and the exercise of operational control by unapproved persons likely resulted in a lack of oversight of flight operations, inattentive and distracted management personnel, and a loss of operational control within the air carrier. However, the investigation could not determine the extent to which any changes to operational control, company management, and FAA oversight would have influenced the pilot's decision to continue the VFR flight into IMC.

Rainbow King Lodge

On September 15, 2015, about 0606 Alaska daylight time, a single-engine, turbine-powered, float-equipped de Havilland DHC-3T (Otter) airplane, N928RK, impacted tundra-covered terrain just after takeoff from East Wind Lake, about 1 mile east of the Iliamna Airport, Iliamna, Alaska. Of the 10 people on board, three passengers died at the scene, the airline transport pilot and four passengers sustained serious injuries, and two passengers sustained minor injuries. The airplane sustained substantial damage. The airplane was registered to and operated by Rainbow King Lodge, Inc., Lemoore, California, as a visual flight rules other work use flight under the provisions of 14 Code of Federal Regulations (CFR) Part 91. Dark night, visual meteorological conditions existed at the departure point at the time of the accident, and no flight plan was filed for the flight. At the time of the accident, the airplane was en route to a remote fishing site on the Swishak River, about 75 miles northwest of Kodiak, Alaska.

Promech Air

The airplane collided with mountainous, tree-covered terrain about 24 miles east-northeast of Ketchikan, Alaska. The commercial pilot and eight passengers sustained fatal injuries, and the airplane was destroyed. The airplane was owned by Pantechnicon Aviation, of Minden, Nevada, and operated by Promech Air, Inc., of Ketchikan. The flight was conducted under the provisions of 14 Code of Federal Regulations (CFR) Part 135 as an on-demand sightseeing flight; a company visual flight rules flight plan (by which the company performed its own flight-following) was in effect. Marginal visual flight rules conditions were reported in the area at the time of the accident. The flight departed about 1207 from Rudyerd Bay about 44 miles east-northeast of Ketchikan and was en route to the operator’s base at the Ketchikan Harbor Seaplane Base, Ketchikan. The accident airplane was the third of four Promech-operated float-equipped airplanes that departed at approximate 5-minute intervals from a floating dock in Rudyerd Bay. The accident flight and the two Promech flights that departed before it were carrying cruise-ship passengers who had a 1230 “all aboard” time for their cruise ship that was scheduled to depart at 1300. (The fourth flight had no passengers but was repositioning to Ketchikan for a tour scheduled at 1230; the accident pilot also had his next tour scheduled for 1230.) The sightseeing tour flight, which the cruise ship passengers had purchased from the cruise line as a shore excursion, overflew remote inland fjords; coastal waterways; and mountainous, tree-covered terrain in the Misty Fjords National Monument Wilderness. Promech pilots could choose between two standard tour routes between Rudyerd Bay and Ketchikan, referred to as the “short route” (which is about 52 nautical miles [nm], takes about 25 minutes to complete, and is primarily over land) and the “long route” (which is about 63 nm, takes about 30 minutes to complete, and is primarily over seawater channels). Although the long route was less scenic, it was generally preferred in poor weather conditions because it was primarily over water, which enabled the pilots to fly at lower altitudes (beneath cloud layers) and perform an emergency or precautionary landing, if needed. Route choice was at each pilot’s discretion based on the pilot’s assessment of the weather. The accident pilot and two other Promech pilots (one of whom was repositioning an empty airplane) chose the short route for the return leg, while the pilot of the second Promech flight to depart chose the long route. Information obtained from weather observation sources, weather cameras, and photographs and videos recovered from the portable electronic devices (PEDs) of passengers on board the accident flight and other tour flights in the area provided evidence that the accident flight encountered deteriorating weather conditions. Further, at the time of the accident, the terrain at the accident site was likely obscured by overcast clouds with visibility restricted in rain and mist. Although the accident pilot had climbed the airplane to an altitude that would have provided safe terrain clearance had he followed the typical short route (which required the flight to pass two nearly identical mountains before turning west), the pilot instead deviated from that route and turned the airplane west early (after it passed only the first of the two mountains). The pilot’s route deviation placed the airplane on a collision course with a 1,900-ft mountain, which it struck at an elevation of about 1,600 ft mean sea level. In the final 2 seconds of the flight, the airplane pitched up rapidly before colliding with terrain. The timing of this aggressive pitch-up maneuver strongly supports the scenario that the pilot continued the flight into near-zero visibility conditions, and, as soon as he realized that the flight was on a collision course with the terrain, he pulled aggressively on the elevator flight controls in an ineffective attempt to avoid the terrain. Although Promech’s General Operations Manual specified that both the pilot and the flight scheduler must jointly agree that a flight can be conducted safely before it is launched, no such explicit concurrence occurred between the accident pilot and the flight scheduler (or any member of company management) before the accident flight. As a result, the decision to initiate the accident tour rested solely with the accident pilot, who had less than 2 months’ experience flying air tours in Southeast Alaska and had demonstrated difficulty calibrating his own risk tolerance for conducting tour flights in weather that was marginal or below Federal Aviation Administration (FAA) minimums. Further, evidence from the accident tour flight and the pilot’s previous tour flights support that the pilot’s decisions regarding his tour flights were influenced by schedule pressure; his attempt to emulate the behavior of other, more experienced pilots whose flights he was following; and Promech’s organizational culture, which tacitly endorsed flying in hazardous weather conditions, as evidenced (in part) by the company president/chief executive officer’s own tour flight below FAA minimums on the day of the accident.

Transwest Air

The float-equipped Transwest Air Limited Partnership DHC-3 turbine Otter (registration C-FSGD, serial number 316) departed Scott Lake, Northwest Territories, at approximately 1850 Central Standard Time on a 33-nautical mile, day, visual flight rules flight to Ivanhoe Lake, Northwest Territories. The aircraft did not arrive at its destination, and was reported overdue at approximately 2100. The Joint Rescue Coordination Centre Trenton was notified by the company. There was no emergency locator transmitter signal. A search and rescue C-130 Hercules aircraft was dispatched; the aircraft wreckage was located on 23 August 2013, in an unnamed lake, 10 nautical miles north of the last reported position. The pilot, who was the sole occupant of the aircraft, sustained fatal injuries.

Rediske Air

Before picking up the nine passengers, the pilot loaded the accident airplane at the operator's base in Nikiski with cargo (food and supplies for the lodge). The operator of the lodge where the passengers were headed estimated the cargo weighed about 300 pounds (lbs) and that the passengers' baggage weighed about 80 lbs. Estimates of the passengers' weights were provided to the lodge operator in preparation for the trip, which totaled 1,350 lbs. The load manifest listed each of these weight estimates for a total weight of 1,730 lbs and did not contain any balance data. The cargo was not weighed, and the pilot did not document any weight and balance calculations nor was he required to do so. The airplane operator did not keep fueling records for each flight. A witness who was present during the fueling operations at the operator's base reported that he saw the pilot top off the front tank then begin fueling the center tank. The first leg of the trip from the operator's base to pick up the passengers was completed uneventfully. According to witnesses at Soldotna Airport, after loading the passengers and their baggage, the pilot taxied for departure. There were no witnesses to the accident. The airplane impacted the ground about 2,320 feet from the threshold of the departure runway and about 154 feet right of the runway centerline. An extensive postcrash fire consumed most of the airplane's cockpit and cabin area, including an unknown quantity of the baggage and cargo. Impact signatures were consistent with a nose- and right-wing-low attitude at impact. The entire airplane was accounted for at the wreckage site. Disassembly and examination of the engine and propeller revealed that both were operating during impact. Examination of the structure and flight control systems found no preimpact malfunctions or failures that would have precluded normal operation. The pilot was properly certificated and qualified in accordance with applicable federal regulations. Toxicological testing of specimens from the pilot was negative for any carbon monoxide, alcohol, or drugs. The airplane was not equipped, and was not required to be equipped, with any type of crashresistant recorder. A video recovered from a passenger's smartphone showed the accident sequence looking out of the row 4 left seat window; the left wing and flaps are in view for most of the sequence and the flap position does not change. The investigation found that the flaps were set to the full-down (or landing) position during takeoff, contrary to recommended procedures in the airplane flight manual (AFM). The recovered video was used to estimate the airplane speed, altitude, and orientation for the portion of the flight where ground references were visible, about 22.5 seconds after the start of the takeoff roll. For the first 12 seconds, the airplane accelerated linearly from the beginning of the takeoff roll through liftoff. The pitch angle decreased slightly in the first 8 seconds as the tail lifted, remained essentially constant for about 4 seconds, and began to slightly increase as the airplane lifted off. Beginning about 14 seconds after the start of the takeoff roll, the speed began decreasing and the pitch angle began increasing. The pitch angle increased at a constant rate (about 2.8 degrees/second), reaching a maximum value of about 30 degrees, and the ground speed decreased from its maximum of about 68 mph to about 44 mph at the end of the analyzed time. The ground references disappeared from the video frame as the airplane experienced a sharp right roll before impacting the ground several seconds later. The low speed, rapid right roll, and pitch down of the airplane is consistent with an aerodynamic stall. The constant pitch rate before the stall is consistent with an aft center of gravity (CG) condition of sufficient magnitude that the elevator pitch down authority was insufficient to overcome the pitching moment generated by the aft CG. Additionally, the flaps setting at the full-down (or landing) position, contrary to procedures contained in the AFM, would have exacerbated the nose-up pitching moment due to the increased downwash on the tail and aft shift of the center of pressure; the additional aerodynamic drag from the fully extended flaps would have altered the airplane's acceleration. Using the data available, the airplane was within weight and balance limitations for the first leg of the trip. However, the cargo loaded was about 2.4 times the weight indicated on the load manifest. Further, the total weight of cargo and baggage in the cargo area, as estimated during the investigation, exceeded the installed cargo net's load limit of 750 lbs by more than 50 lbs. Although the loaded cargo actual weight was higher than indicated on the load manifest, the flight from Nikiski to Soldotna was completed without any concerns noted by the pilot, indicating that even with the higher cargo load, the airplane was within the normal CG range for that leg of the flight. Thus, based on the investigation's best estimate and a calculation of the airplane's weight and balance using the recovered passenger weights, weights and location of the luggage recovered on scene, weight of the cargo recovered on scene, and weights accounting for the liquid cargo destroyed in the postimpact fire, once the passengers were loaded, the airplane weight would have exceeded the maximum gross weight of 8,000 lbs by about 21 lbs and the CG would have been at least 5.5 inches aft of the 152.2-inch limit (a more definitive calculation could not be performed because the exact location of the cargo was not known). Additionally, the kinematics study of the accident airplane's weight and motion during initial climb and up to the point of stall found that with the pilot applying full pitch-down control input, the CG required to produce the motion observed in the video was likely just past 161 inches. Thus, the only way for the airplane motion to match the motion observed in the video was for the CG to be considerably aft of the 152.2-inch limit, which provides additional support to the results from the weight and balance study. Based on the video study, the weight and balance study constructed from available weight and balance information, and the kinematics study, the airplane exceeded the aft CG limit at takeoff, which resulted in an uncontrollable nose-up pitch leading to an aerodynamic stall. The CG was so far aft of the limit that the airplane likely would have stalled even with the flaps in the correct position. Neither 14 CFR Part 135 nor the operator's operations specifications (OpSpec) require that the aircraft weight and balance be physically documented for any flights. However, according to Section A096 of the OpSpec, when determining aircraft weight and balance, the operator should use either the actual measured weights for all passengers, baggage, and cargo or the solicited weights for passengers plus 10 lbs and actual measured weights for baggage and cargo. The operator did not comply with federal regulations that require adherence to the weighing requirements or the takeoff weight limitations in the AFM. Additionally, although the inaccurate estimate of 300 lbs for the cargo resulted in a calculated CG that was within limits for both legs of the flight, the actual weight of the cargo was significantly higher. Once loaded in Soldotna, the combination of the passengers, their baggage, and the actual cargo weight and its location resulted in the CG for the accident flight being significantly aft of the limit. With the CG so far aft, even with full nose-down input from the pilot, the nose continued to pitch up until the airplane stalled. For each flight in multiengine operations, 14 CFR 135.63(c) requires the preparation of a load manifest that includes, among other items the number of passengers, total weight of the loaded aircraft, the maximum allowable takeoff weight, and the CG location of the loaded aircraft; one copy of the load manifest should be carried in the airplane and the operator is required to keep the records for at least 30 days. Single-engine operations are excluded from this requirement. The NTSB attempted to address this exclusion with the issuance of Safety Recommendations A-89-135 and A-99-61, which asked the Federal Aviation Administration (FAA) to amend the record-keeping requirements of 14 [CFR] 135.63(c) to apply to single-engine as well as multiengine aircraft. The FAA did not take the recommended action in either instance, and the NTSB classified Safety Recommendations A-89-135 and A-99-61 "Closed—Unacceptable Action" in 1990 and 2014, respectively.