The natural scenery just northeast of Ketchikan, Alaska, is a magnet for tourists, and an air tour industry has grown up to serve them. The airspace in the area is mostly uncontrolled and pilots must cooperate to stay separated from one another. In the summer months, when the flights are frequent and many aircraft fly in the same small area, that becomes difficult. On May 13, 2019, the operators’ informal system for separation broke down with tragic results.

As they were returning from tours of an area known as Misty Fjords, two floatplanes converged on a point about 8 mi. northeast of Ketchikan International Airport (PAKT). The skies were clear. At 1221 Alaska Daylight Time, a de Havilland DHC-3 (Otter), N959PA, struck a de Havilland DHC-2 (Beaver), N952DB, and both airplanes crashed in the vicinity of an area known as the George Inlet. Of the 10 passengers on board the Otter, nine suffered serious injuries and one died. The pilot escaped with minor injuries. The passengers on board the Beaver were not so lucky. All four and the Beaver pilot died.

Two minutes before the collision, the Otter was above and slightly behind the Beaver. At that time, the Otter began a shallow descent out of 4,000 ft. and the Beaver was climbing through 3,175 ft. The Beaver then leveled off at 3,350 ft. The Otter struck the Beaver on its right side in the vicinity of the right aileron. A series of mechanical cuts were found on the aft portion of the wing from the right aileron inboard to the wing root, showing where the Otter’s propeller had cut a sawtooth pattern into the Beaver’s wing structure.

The Beaver broke up into multiple pieces and impacted the water and terrain immediately below the collision site. The Otter rolled into a 50-deg. right bank and turned back in the direction it had come from, descending rapidly and crashing into the George Inlet 1 min. after the collision.

In an interview, the Otter pilot remembered seeing a flash of red and white just before the collision. The windshield broke and the passenger in the right seat fell over toward him. The wind force in his face was very high. His vision was blurry, but he could see the prop was stopped and the blade was broken about halfway up the shaft. He applied full right rudder and used both hands on the yoke to try to keep the wings level. He took the condition lever to cutoff and the feather lever to feather and tightened his seat belt. As he approached the water, he was able to flare the airplane and maintain a flat attitude until the first float struck the water.

The airplane pitched over very violently. As it stopped, the pilot found himself underwater. After unlatching his seat belt and untangling himself from cords and wires, he swam up toward the surface and emerged behind the right wing. He opened the right door and began to assist passengers to evacuate the airplane. All the passengers except the injured person in the right cockpit seat were able to leave the airplane.

Within about 4 min., a person in a nearby small skiff approached the sinking airplane and began towing survivors to the shore, which was about 100 yd. away. The U.S. Coast Guard launched a boat and a helicopter, and several commercial helicopters flew to the scene to assist. The survivors and three of the deceased occupants of the Beaver were taken to a local hospital. The Otter passenger who did not survive was located later in the evening and the two remaining Beaver occupants were found in a wooded area the following day.

The 46-year-old pilot of the Beaver was the owner and sole pilot for Mountain Air Service, an FAR Part 135 on-demand operator. He held a commercial pilot certificate with ratings for airplane single-engine land and sea, multiengine land and sea, and instrument airplane. He also held a flight instructor certificate with ratings for airplane single-engine land and instrument airplane. His most recent FAA second-class medical certificate was dated April 29, 2019, with no limitations. He had flown for several other floatplane operators in Alaska before starting his own business and had accrued about 11,000 total hours of flight time. At the time of the accident, the tour season had just begun. He was only on duty for two days in April and had logged 15 hr. in May. His training, proficiency and certification history was spotless.

The Otter pilot worked for Taquan Air, another Part 135 operator. He held an airline transport pilot certificate with a rating for airplane multiengine land and commercial privileges for airplane single-engine land and airplane single-engine sea. He also held a flight instructor certificate with ratings for single-engine and multiengine land and instrument airplane. The pilot was 60 years of age and estimated that he had about 25,000 total flying hours, of which 15,000 were as pilot-in-command (PIC). He had flown T-38s and C-130s in the U.S. Air Force and a variety of Boeing airliners as an airline pilot, and he had been a check airman at his airline. He had retired early from his airline job. He had owned and flown a floatplane in the Anchorage area, and he estimated he had about 1,000 hr. of floatplane flight time. He had 550 hr. flying the Beaver and 20 to 25 hr. flying the Otter. He had a first-class medical certificate with a requirement to wear corrective lenses and possess glasses for near or intermediate vision.

The Otter pilot had flown one season with Taquan Air and was beginning his second summer season of operation there. He had been on duty three days in April and had completed his competency and line check on April 25. He had been on duty for eight days in May and had accrued 33.6 hr. during that time.

Ketchikan International Airport and the nearby Ketchikan Harbor Seaplane Base (5KE) are located in Class E controlled airspace, but there is no tower. Aircraft operating in and out of the two runways must be in contact with the Ketchikan Flight Service Station (FSS) under rules explained in SFAR 93. The dimensions of the Class E airspace are shown on the Ketchikan sectional chart and the details of SFAR 93 are listed in the margin of that chart. The airspace outside the airport area is Class G uncontrolled airspace. There is an ADS-B ground station near the airport, but no other ATC services are available at the low altitudes where the seaplanes operate.

The town of Ketchikan is located on a narrow strip of land in the southeast Alaska Inside Passage, and it’s surrounded by steep and forested terrain. The rugged landscape is interspersed with dozens of channels, inlets and passages, making it an ideal location for floatplanes. According to city visitor statistics, 40 cruise ships made over 500 stops in Ketchikan from April to September 2018, carrying over 1 million passengers. The 2019 numbers were likely very similar. These cruise ships provide a steady flow of sightseers eager to fly out to Misty Fjords and other local scenic spots.

To serve these customers, there were a dozen or more floatplane and helicopter operators in the area in 2019. These tour operators created a voluntary and non-binding letter of agreement in 2009 to establish safe practices, provide horizontal and vertical separation of aircraft, and standardize the radio frequencies to be used. Using maps of the area, the agreement spelled out specific radio frequencies, altitudes to be flown, procedures for choke points, standard routes and reporting points, and best practices. Although standard routes were provided, operators could take non-standard routes if they chose, with the recommendation that they announce their actions more frequently over the radio. The map in the agreement showing the return from Misty Fjords to the airport depicted a straight line between the two and indicated returning aircraft should fly at 500 ft., 1,500 ft., 2,500 ft. or hemispherical altitudes.

The original voluntary agreement was based on the principle of “see and avoid,” prescribed in FAR Part 91.113 (b). “See and avoid” has long been understood as limited ineffectiveness. One notable example was the collision between a Twin Otter and a Bell 206B helicopter in the Grand Canyon in 1986. The NTSB said those sightseeing aircraft collided due to a failure to “see and avoid” for unknown reasons. The reasons are better known today.

The Safety Board has found that common routes and a limited number of scenic points overflown by air tour operators is a unique risk factor for midair collisions of those operators. Midair collisions represent 2.1% of all fatal accidents in the U.S. but are 7% of all fatal accidents in Part 135 sightseeing accidents.

In an effort to improve on purely visual separation schemes, both of the Ketchikan accident airplanes were equipped with ADS-B In and Out. Since ADS-B was invented long after the airplanes were manufactured, their avionics were add-ons on top of add-ons. The Beaver, which was built in 1951, had a FreeFlight RANGR 978 transceiver, a TC-978 controller and a Wi-Fi controller. An iPad mounted on the center console had a ForeFlight mobile application that displayed traffic information via the Wi-Fi connection. The ForeFlight display was capable of generating aural and visual traffic alerts from aircraft in close proximity.

The Otter, which was built in 1956, had a Pratt & Whitney Canada PT6A turboprop engine, a RANGR 978 transceiver and a Garmin GSL 71 control panel. It also had two Chelton FlightLogic electronic flight instrument system (EFIS) display units. One was set up to display flight parameters like altitude, airspeed, attitude and heading. The other showed navigation data on a moving map. The Chelton map display showed traffic information and was capable of generating aural and visual traffic alerts, but since the RANGR 978 was not designed to send alert messages, the Otter could not generate aural or visual traffic alerts.

Editor's Note: Roger Cox examines the accident investigation and highlights recommended changes in the following article.