De Havilland DHC-3 Otter

The single engine airplane was flying to Pluto Lake to pick up a family from a fishing camp. On board were a pilot and a passenger. Upon landing on Pluto Lake, the airplane went out of control, lost its wings, plunged into the water and came to rest. The passenger was unhurt and the pilot was injured and airlifted to Chibougamau. This aircraft was already severely damaged in a previous accident on 20 June 1985. It was repaired and returned into service more than 18 years later.

On September 4, 2022, about 1509 Pacific daylight time, a float-equipped de Havilland DHC-3 (Otter), N725TH, was destroyed when it impacted the water in Mutiny Bay, near Freeland, Washington, and sank. The pilot and nine passengers were fatally injured. The airplane was owned by Northwest Seaplanes, Inc., and operated as a Title 14 Code of Federal Regulations (CFR) Part 135 scheduled passenger flight by West Isle Air dba Friday Harbor Seaplanes. The flight originated at Friday Harbor Seaplane Base (W33), Friday Harbor, Washington, with an intended destination of Will Rogers Wiley Post Memorial Seaplane Base (W36), Renton, Washington. Visual meteorological conditions prevailed at the time of the accident. The accident pilot was scheduled to fly the accident airplane on three multiple leg roundtrips on the day of the accident. The first roundtrip flight was uneventful; it departed from W36 about 0930, made four stops, and returned about 1215. The accident occurred during the pilot’s second trip of the day. A review of recorded automatic dependent surveillance–broadcast (ADS-B) data revealed that the second roundtrip departed 36 about 1253 and arrived at Lopez Seaplane Base, (W81), Lopez Island, Washington, about 1328.2 The data showed that the flight then departed W81 and landed at Roche Harbor Seaplane Base (W39) about 1356. The airplane departed W39 about 1432, arrived at W33 about 1438, and departed about 1450. According to ADS-B data, after the airplane departed W33, it flew a southerly heading before turning south-southeast. The en route altitude was between 600 and 1,000 ft above mean sea level (msl), and the groundspeed was between 115 and 135 knots. At 1508:40, the altitude was 1,000 ft msl, and the groundspeed had decreased to 111 knots. Based on performance calculations, at 1508:43, the airplane pitched up about 8° and then abruptly pitched down about 58°. The data ended at 1508:51, when the airplane’s altitude was 600 ft msl and the estimated descent rate was more than 9,500 ft per minute (the flightpath of the airplane is depicted in figure. Witnesses near the accident site reported, and security camera video confirmed, the airplane was in level flight before it entered a slight climb and then pitched down. One witness described the descent as “near vertical” and estimated the airplane was in an 85° nose-down attitude before impact with the water. Several witnesses described the airplane as “spinning,” “rotating,” or “spiraling” during portions of the steep descent. One witness reported hearing the engine/propeller and noted that he did not hear any “pitch change” in the sounds. The airplane continued in a nose-low, near-vertical descent until it impacted water in Mutiny Bay.

The purpose of the flight was to transport three passengers and cargo. The pilot reported that, during takeoff, the airplane’s tail came up slightly lowered to the runway when he attempted to raise the tail by applying forward elevator. He stated that he thought this was unusual and attributed it to an aft-loaded airplane. He applied additional nose-down trim and departed without incident. While en route, the tail of the airplane seemed to move up and down, which the pilot attributed to turbulence. Upon arrival at his destination, the pilot entered a left downwind, reduced the power and extended the flaps to 10° abeam the end of the runway. He turned onto the base leg about ½ mile from the approach end of the runway and slowed the airplane to 80 mph. Turning final, he noticed the airplane seemed to pitch up, so he applied full nose-down pitch trim and extended the flaps an additional 10°. On short final he applied full flaps, and the airplane abruptly pitched up to about a 45° angle. He stated that he applied full nose-down elevator, verified the pitch trim, and reduced the power to idle. When the airplane was about 300 ft above ground level, the airplane stalled, the left wing dropped slightly, and the airplane entered about a 45° nose-down dive. After allowing the airplane to gain airspeed, the pilot applied full back elevator. The airplane impacted forested terrain near the approach end of runway 23 at an elevation of about 18 ft. A postaccident examination of the airframe and engine revealed no evidence of preaccident mechanical malfunctions or failures that would have precluded normal operation. Elevator and rudder control continuity was confirmed from the cockpit to the respective control surfaces. The airplane's estimated gross weight at the time of the accident was about 7,796 lbs and the airplane's estimated center of gravity was about 3.2 to 5.6 inches beyond the approved aft limit. Maximum gross weight for the airplane is 8,000 lbs.

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.

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.

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.