History of Flights

Otter N959PA – The DHC-3 Otter floatplane operated by Taquan Air departed from Rudyerd Fjord, approximately 40 miles northeast of Ketchikan, with ten passengers on a scenic flight. The flight was part of a "boat fly" operation where the passengers inbound to the fjord are deplaned at a large floating dock, and outbound passengers board and continue the air tour, ultimately landing at the company’s Ketchikan Harbor Seaplane base. The Otter departed the fjord at approximately 1203, flying toward the southeast with the intention of flying over Manzoni Falls before turning southwest to return to Ketchikan.

Beaver N952DB – The DHC-2 Beaver floatplane operated by Mountain Air Services with four passengers and one pilot onboard also departed Rudyerd Fjord for a sightseeing flight that would include a viewing of Manzoni Falls before returning to Ketchikan.

Airplane Details

Otter N959PA – The DHC-3 Otter is a single-engine, propeller-driven, high-wing, short-takeoff-and-landing (STOL) airplane with a cruciform tail. This Otter was powered by a Pratt & Whitney PT6A turboprop engine, equipped with Edo 7490 floats, and configured for one pilot and ten passenger seats. The Otter was manufactured in 1956 and had accumulated more than 30,000 hours on the airframe at the time of the accident. Taquan Air began operating the airplane in 2016.

Beaver N952DB – The DHC-2 Beaver is a single-engine, propeller-driven, high-wing STOL airplane. This Beaver was powered by a Pratt & Whitney R-985 radial engine and equipped with Edo 58-4580 floats. The airplane was configured with one pilot and six passenger seats. The airplane was built in 1951 and had accumulated approximately 16,500 airframe hours at the time of the accident. Mountain Air Services acquired the Beaver in 2012.

Collision Avoidance Details and See and Avoid Best Practices

Per 14 CFR 91.113 Right of Way rules during the VFR flight, pilots are required to "maintain vigilance" to "see and avoid" other airplanes. There are multiple challenges, including physiological and environmental conditions; airplane structure and blind spots; and operational distractions that leave “even the most diligent pilot vulnerable to the threat of a midair collision with unseen aircraft,” according to the NTSB.

This video produced by the US Helicopter Safety Team (USHST) discusses many of the best practices for all aircraft, not just helicopters.

According to the U.S. Air Force, nearly all midair collisions occur within five miles of an airport during the day and in VFR conditions. Most of these accidents involve relatively slow closing speeds, such as an aircraft being overtaken or aircraft converging on final approach.

When pilots do see a traffic conflict, they are required to alter their course to the right for head-on scenarios; and when overtaking another aircraft from behind, they are required to alter their course to the right and to pass "well clear."

The key to an avoidance maneuver is to see the traffic. The FAA provides information and best practices to aid pilots in identifying traffic threats, including the following:

Information:

• A distant aircraft on a collision course appears small and motionless. It remains this way for a relatively long time, then suddenly "blooms" into a mass filling airplane windows.
• Varicolored terrain or areas heavily dotted with buildings can cause traffic to blend into the background until it is quite close.

Best Practices:

• During the walk-around inspection, pilots should verify the windshield is clean from dirt and debris that may hide airborne traffic. All windows should also be clear of obstructions, such as solid sun visors and curtains.
• When a pilot’s vision is partially blocked by a windshield post or other object, they should move their head position, not just their eyes, when scanning for traffic.
• Flying above the haze layer on a hazy day helps pilots identify oncoming traffic.
• Strobes and rotating beacons make an airplane more visible to other aircraft.
• Using landing lights in the traffic pattern, whether day and night, increases the chances of being seen.
• When approaching an airport, whether planning for a landing or not, pilots should make a radio call when 15 miles from a towered airport and 10 miles from a non-towered airport to announce position, altitude, and intentions.
• When participating in VFR flight with ATC advisories (flight following), pilots should never assume that ATC provides alerts to all traffic in the vicinity. ATC traffic services for VFR aircraft are provided on a workload-permitting basis.
• Although passengers frequently are not pilots, they can assist in the pilot’s see-and-avoid responsibility. Pilots should train their passengers how to be observers of traffic. (Credit: Tom Turner: Flying Lessons; June 20, 2024)
  • Show passengers what a typical general aviation airplane looks like at a distance of concern (1 mile or less), for example in the traffic pattern.
  • Advise passengers about the "o'clock" system for identifying an airplane's position relative to one’s own position, using phrases such as, "I see traffic, 3 o'clock, level."

ADS-B Systems

Technology in the cockpit that displays or alerts pilots to conflicts with nearby aircraft can aid in the see-and-avoid process. ADS-B is one such system that is readily available in the United States to the general aviation (GA) community at relatively low cost. As of January 1, 2020, ADS-B Out is required for flight in certain airspace (see graphic) and, to date, a large percentage of the GA fleet is equipped. ADS-B Out sends an aircraft's position, velocity, and other data to other aircraft in the vicinity and to the FAA's ADS-B ground network. When coupled with onboard ADS-B In and displayed on a traffic application, which are relatively inexpensive to acquire, pilots have a powerful tool to help compensate for the inherent limitations of see-and-avoid, reducing midair collision risk.

ADS-B Out systems for GA aircraft generally use the GPS global navigation satellite system augmented with the FAA’s Wide Area Augmentation System (WAAS) that enhances accuracy and integrity to generate precise location information for air traffic control surveillance and for aircraft-to-aircraft traffic awareness.

When equipped with ADS-B Out, an aircraft broadcasts its satellite-based position, altitude, velocity, and other data at a rate of once per second to aircraft in the vicinity and to the FAA through a nationwide network of ADS-B ground stations. Nearby aircraft equipped with ADS-B In, an installed or portable display, and a traffic application receive traffic information and generally provide visual and aural alerts.

The FAA fuses ADS-B data with surveillance data from legacy radar systems (which includes aircraft using Mode C transponders) and rebroadcasts the data to aircraft in the vicinity of the ground stations, providing pilots with a comprehensive picture of transponder- and ADS-B-equipped aircraft in the area. Note that gliders, ultralights, and other aircraft that are not equipped with ADS-B or legacy Mode C transponders will not show up as ADS-B In traffic.

When an aircraft is equipped with suitable and correctly operating ADS-B Out and In with an installed or portable display, pilots see nearby traffic as blue arrowhead symbols. Nearby aircraft in "alert status" are displayed as yellow or red targets, depending on proximity. Flight navigation software applications generally provide a popup message on the screen and aurally when an ADS-B target approaches to within certain horizontal and vertical thresholds of an aircraft, also referred to as ownship. The alert notes the target's clock position, distance, and relative altitude.

Video of enhancing see and avoid with ADS-B technology. Source: FAA/John Croft

Prior to takeoff, pilots should verify that the ADS-B system is configured and operating per applicable checklists. Post-flight, pilots should frequently (or at least annually) check the performance status of their ADS-B system by requesting a no-cost Public ADS-B Performance Report (PAPR). Elements that do not meet performance requirements are highlighted in red in the report.

Missing Elements:

If pilots experience issues with ADS-B while flying, for example, if receiving false traffic targets, they should report the anomalies to the FAA at this link: ADS-B Services: Report an Issue.

Pilots should also be aware that while ADS-B provides traffic alerts, it does not provide resolution advisories (RA) to avoid a collision as do certain Traffic Alert and Collision Avoidance Systems (TCAS) required by the FAA for commercial transport airplanes. There are two types of TCAS, I and II. TCAS I, which provides traffic advisories (TAs) only, is required on all turbine-powered, passenger-carrying airplanes with ten to 30 seats. TCAS II, which is required on all commercial airplanes with more than 30 seats or a maximum takeoff weight of more than 33,000 lbs., issues TAs and RAs, which provide pilots with vertical guidance to avoid a collision.

For a detailed discussion on TCAS, see the Overview section of the lessons learned module from the July 1, 2002 midair collision between a Bashkirian Airlines TU154M and a DHL Boeing 757-200 over Überlingen, Germany.

ADS-B Equipage in this Accident

Although both airplanes involved in the Ketchikan midair collision were equipped with the ADS-B avionics and displays capable of generating visual and aural alerts, there were various issues that prevented both pilots from receiving alerts, as shown in the table.

Otter N959PA – The DHC-3 Otter was equipped with ADS-B Out and In, using an installed transceiver and a panel-mounted display to aid the pilot in traffic awareness. A selector knob on a separate control panel was required to be in the ON position for the airplane’s barometric altitude and transponder code to be broadcast to the ADS-B ground network and to other airplanes. The NTSB, in its post-crash investigation, found that the selector knob was in the OFF position. The avionics installation in this airplane did not provide, nor was it required to provide, a traffic alerting option for the pilot.

Beaver N952DB – The DHC-2 Beaver was equipped with ADS-B Out and In using an installed transceiver and an onboard wireless network that allowed the pilot to display ADS-B traffic and other information on a portable iPad running the ForeFlight navigation application. In post-crash simulations, NTSB investigators could not determine if the Otter had been displayed as traffic on the Beaver pilot’s iPad. They determined that given the lack of altitude information being broadcast by the Otter, the Beaver pilot would not have received a visual or aural alert from ForeFlight.

The Collision

The Otter pilot, during interviews with the NTSB and FAA, recalled seeing "two groups of blue triangles" representing airborne traffic on the traffic display in the minutes leading up to the collision, but those were to the left of course and the pilot did not consider them to be a threat based on location. The pilot also discussed the various tour operator tasks which competed with see-and-avoid responsibilities.

Distractions noted by the pilot included operating the VHF and company-specific radios, operating an iPhone that provides music to the passengers, checking the surface of lakes to determine wind direction for planning a landing if the engine were to fail, as well as pointing out interesting sights to the passengers. Regarding the collision, the pilot remembered seeing a flash out of his peripheral vision and seeing "white and red" before feeling a "tremendous collision." He did not remember seeing the Beaver show up as traffic on the display, and as the NTSB later determined, the avionics did not provide a visual or aural notification.

In the NTSB's cockpit visibility study, investigators determined that in the three minutes prior to the collision, the Beaver pilot would not have been able to see the Otter, which was above and behind his airplane. The Otter was obscured by the cockpit structure, the right wing, and the passenger in the right front seat. The obscuration, as well as a full timeline of the crash, is available in this NTSB video.

Accident sequence. Source: NTSB

The Otter pilot could not see the Beaver due to its relative stationary position and the layout of the Otter cockpit. Aircraft on a collision course appear to be motionless to the pilot, except for the aircraft gradually becoming larger in the windscreen and eventually blooming just before the collision. In this case, the Beaver was hidden from the Otter pilot's line of sight by the left window post. It was not until about one second before the crash that the pilot would have begun to see the Beaver emerging ahead of the left window post.

The NTSB determined that had the Otter pilot's head been positioned three inches farther forward, the Beaver may have been visible for about 51 seconds prior to the accident. Researchers note that it takes about 12 seconds for an unaware pilot to spot traffic with a closure rate of 120 kts, identify it as a threat, and initiate an evasive maneuver. Pilots who have ADS-B In with visual and aural traffic alerts can expect to visually acquire the conflicting traffic, in this example, about eight seconds earlier.

The airplanes ultimately collided due to the inability of both pilots to see and avoid the other airplane, combined with the lack of visual and aural alerting from the installed ADS-B systems.

Overview of GA Midair Collisions

According to the GA Fatal Aircraft Accident Pareto published by the General Aviation Joint Safety Committee (GAJSC) and based on NTSB data, midair collisions (MAC) were ninth in the top causes of fatal GA accidents between 2008 and 2021.

NTSB data shows that from 2012 through 2021, there were an average of seven midair collisions per year, about half of which resulted in fatalities. Most accidents occurred in the en route phase of flight, followed by the maneuvering and approach phases.

The NTSB determined that the probable cause of this accident was the "inherent limitations of the see-and-avoid concept" that created a scenario where the pilots of each aircraft did not see each other before the collision. The NTSB also determined a probable cause was the absence of visual and aural alerts about the impending collision while operating in a geographical region with a high concentration of air tour activity.

The NTSB's report included 12 findings. Following are select findings related to and the availability of ADS-B equipage on a voluntary basis:

• Because of the high concentration of traffic in popular air tour areas, the risk of collision is higher than in the general National Airspace System, and technology that supplements pilots' traffic scans by providing aural and visual alerts can mitigate this risk.
• Aural and visual alerts that draw the pilots' attention to conflicting traffic presented on the cockpit display of traffic information can greatly increase the pilots' awareness of potentially conflicting traffic and help avoid a collision.
• Although existing ADS-B traffic alerting applications can help draw pilots' attention to conflicting traffic, these applications are currently not required.

View Accident Board Findings

NTSB accident report: AAR-21/04

Back to top

The NTSB issued ten new recommendations (six to the FAA; one to ForeFlight; one to Taquan Air; one to aviation industry groups; one to the National Association of Flight Instructors and the Society of Aviation Flight Educators) and reiterated one previously issued recommendation to the FAA. Included in the recommendations were:

• FAA to require Part 91 and Part 135 air tour companies operating in identified high-traffic areas to equip with ADS-B Out and ADS-B In systems that include visual and aural alerts during all flight operations, and all non-tour aircraft operating in this same high-traffic airspace be equipped, at a minimum, with ADS-B Out
• FAA to update the Aeronautical Information Manual and Pilot’s Handbook of Aeronautical Knowledge to include limitations inherent in visual scanning for traffic and benefits of using ADS-B traffic to supplement visual scanning
• Aviation groups (AOPA, EAA, NBAA etc.) and flight instructor organizations to inform members of the importance of including the traffic display when scanning for traffic in both initial and recurrent pilot training

Full list of NTSB recommendations

Back to top

Back to top

Throughout aviation history, high-profile accidents have driven government and industry to deploy safety technologies that have in many cases all but eliminated those types of accidents. This has been true for midair collisions in commercial aviation through the incremental deployment over time of procedural and technological improvements. This animation provides a timeline of the high-profile accidents that led the way to a drastic decrease in the number of midair collisions in the airline sector. The FAA's expectation is that ADS-B can provide similar improvements for the GA community.

Back to top

The inherent limitations of the see-and-avoid concept – Both pilots’ ability to visually acquire the other airplane was compromised by their restricted field of view from the cockpit (based on passenger seating, airplane structure, etc.).

The risk of midair collisions in high-traffic areas – Pilots and operators can reduce accident risk by supplementing visual scans with ADS-B Out- and In-supported traffic advisory systems with aural and visual alerts, particularly when operating in high-density and/or task-saturated environments.

The lack of traffic alerting on both airplanes – Although both airplanes were equipped with ADS-B Out, ADS-B In, and cockpit displays, configuration settings and software notification capabilities resulted in neither pilot being alerted to the impending collision. Had these issues not existed, aural traffic alerts in each airplane may have occurred early enough for the pilots to have prevented the collision.

Back to top

Pilots and operators who have equipped their aircraft with ADS-B Out and In receive traffic alerts that minimize the risk of midair collisions.

• In this accident, the DHC-2 Beaver did not receive a traffic alert regarding the DHC-3 Otter because the Otter’s avionics were not properly configured. The Otter pilot could not have received a traffic alert regarding the Beaver as the Otter’s avionics did not have the capability to issue a traffic alert.

The potential for midair collisions can be reduced by pilots scanning the horizon.

• In this accident, see-and-avoid practices alone were not sufficient to alleviate the collision risk. Visual constraints, including the front seat passenger and airplane structure, prevented the DHC-2 Beaver pilot from seeing the DHC-3 Otter. For the Otter pilot, structural components in the cockpit prevented the pilot from seeing the Beaver, which, given the collision course, would have been a relatively fixed position in the windscreen.
• Pilots operating in high-density or air tour operations may have duties associated with passenger comfort and tour guide entertainment that can potentially compete with higher priority see-and-avoid responsibilities.

Back to top

Incomplete Capstone 2 Avionics Upgrade

As part of the FAA’s Capstone 2 program in Alaska, the agency updated the ADS-B avionics in all participating aircraft, including the DHC-3 Otter. While the Capstone 1 avionics included a traffic alerting function, the new transceivers for Capstone 2 did not. The NTSB concluded that the FAA had not mitigated the increased risk due to the reduced functionality, and as such, included the incomplete upgrade as a contributing factor in the accident.

Eurocopter AS350BA, Liberty Helicopters, N401LH; Piper PA-32R-300 N71MC, Hoboken, New Jersey, August 08, 2009

A Piper PA-32R-300 collided with a Eurocopter AS350BA air tour helicopter over the Hudson River near Hoboken, New Jersey. Both aircraft were equipped with transponder-based traffic information service (TIS) avionics, which could generate a visual display of traffic. The NTSB determined the probable cause of the accident to be the inherent limitations of the see-and-avoid concept, which made it difficult for the airplane pilot to see the helicopter until the final seconds before the collision. Contributing to the accident were both pilots’ ineffective use of the TIS to maintain awareness of nearby aircraft.

NTSB accident report: ERA09MA447

Eurocopter EC-135-P2, PHI Inc, N312PH; Cessna 172H, N2876L, Weyers Cave, Virginia, December 31, 2010

A Eurocopter EC-135-P2 helicopter collided with a Cessna 172H as the two aircraft were approaching the Shenandoah Valley Regional Airport. The Eurocopter was equipped with a traffic collision avoidance device (TCAD) which receives input from the Mode C transponders of nearby aircraft. The helicopter crew recalled seeing traffic information for other aircraft in the pattern, but not for the accident C172. The NTSB determined the probable cause the accident to be the inherent limitations of the see-and-avoid concept which made it difficult for the helicopter pilot to see the aircraft before the collision (the helicopter descended into the C172). Because of the high-wing configuration of the C172 and its relative position and altitude with respect to the helicopter, the C172 pilot would not have been able to see the helicopter before the collision.

NTSB accident report: ERA11FA101

Back to top

Updated ADS-B Technical Standard Order (TSO)

Since the accident, there have been several updates to the ADS-B TSO 195c including adding a requirement that ADS-B In have ATAS (ADS-B Traffic Advisory System).

• ATAS includes audio alerting
• If target traffic lacks barometric altitude information, then the TSO C195c avionics must use the traffic geo-referenced altitude versus the ownship-referenced geo altitude data for traffic alerting

Updated Ketchikan Operators Agreement

As a result of this accident, a group of 14 Ketchikan commercial operators updated a Letter of Agreement (LOA). Originally created in January 2009, the LOA was confirmation of voluntary compliance with the routes, procedures, and safe practices established for operating in the Ketchikan and Misty Fjords National Monument Wilderness area. Taquan Air was one of the operators that signed the LOA. Additionally, Taquan Air had each of its pilots sign a document stating they read and fully understood the LOA and agreed to comply with it. The update specifically addressed certain best practices to follow, including:

• Use of anti-collision lights, "pulse" lights, or aircraft landing lights at all times when aircraft are being flown
• All company aircraft equipping with and using ADS-B Out and In at all times
• All pilots announcing position reports at all reporting points identified in the agreement

View the full list of best practices from the LOA here.

Update to midair collision avoidance best practices in the Aeronautical Information Manual (AIM) and the Pilot's Handbook of Aeronautical Knowledge (PHAK)

The FAA in November 2022 published revised text for the AIM, Section 4-4-15, Use of Visual Clearing Procedures and Scanning Techniques, on the benefits and best practices of using cockpit displays of traffic information to supplement visual scans. The FAA is incorporating a similar update to the PHAK. This action was in direct response to the NTSB recommendation that the FAA update the Aeronautical Information Manual and the Pilot’s Handbook of Aeronautical Knowledge to include the limitations inherent in visual scans for traffic and the benefits and best practices of using cockpit displays of traffic information to supplement visual scans to help overcome these limitations.

Update to traffic alerting algorithms in ForeFlight

ForeFlight has modified the software in its traffic application so that aircraft not reporting geometric altitude or pressure altitude are displayed as a target at the same altitude as the ownship for the purposes of alerting. In discussions between NTSB and ForeFlight, the NTSB recommended and ForeFlight agreed to update its traffic alerting algorithms so that traffic targets for which there is no altitude information are assumed to be at the same altitude as the ownship.

New Special Federal Aviation Regulation (SFAR)

The FAA is moving forward with an SFAR, anticipated in 2028, for the Misty Fjords area. The SFAR will include:

• A definition of the boundaries of the Misty Fjords area for the purpose of the SFAR
• A requirement for increased VFR weather minimums
• A requirement for ADS-B In and Out
• A requirement that all air tour operators in the Misty Fjords area must be Part 135
• Operators must provide floatation devices and instructions for use
• Operators must provide pre-flight passenger briefing on water ditching procedures

Back to top

None.

Back to top

Small Airplane Life Cycle

• Operational

Accident Threats

• Midair Collisions/Incursion

Operations

• Business/Commercial

Accident Common Themes

• Human Error
• Flawed Assumptions

Back to top 

Back to top

Piper PA-28-181 (Archer), Robinson R22, Chandler, Arizona, October 1, 2021

The low-wing Piper Archer and an R22 helicopter, both with flight instructors on board, were conducting takeoffs and landings at the tower-controlled airport in daytime VFR conditions. The R22 was flying a right-handed pattern to a taxiway that paralleled the runway to which the Piper was flying right-handed patterns, outside and above the Robinson. The collision occurred when the Piper instructor performed an engine-out maneuver to the runway and descended into the R22. The NTSB determined the probable cause of the accident was the failure of the pilots in the Piper to see and avoid the helicopter while maneuvering in the traffic pattern, which resulted in a midair collision. Both aircraft were equipped with ADS-B. The Piper aircraft had a portable traffic display, but the flight instructor did not recall receiving any traffic advisories related to the R22.

NTSB accident report: WPR22FA001

Trans World Airlines Lockheed L-1049 Super Constellation, United Airlines Douglas DC-7, Grand Canyon, Arizona, June 30, 1956

On June 30, 1956, TWA Flight 2, a Lockheed Super Constellation, collided with United Air Lines Flight 718, a Douglas DC-7, over the Grand Canyon. Both airplanes fell into the canyon. There were no survivors among the 128 persons aboard the flights. This accident involved two of the largest commercial airplanes in service and was the deadliest aviation disaster in history at that time. It was a catalyst for changes to the air traffic control system and led to the creation of the FAA.

Library module: Lockheed L-1049 Super Constellation and Douglas DC-7

Pacific Southwest Airlines Boeing 727-214, Cessna 172, San Diego, California, September 25, 1978

On September 25, 1978, Pacific Southwest Airlines, Inc., Flight 182, a Boeing 727-214, and a Gibbs Flite Center, Inc., Cessna 172, collided in midair about three nautical miles northeast of Lindbergh Field, San Diego, California. Both airplanes crashed in a residential area. All 137 people on both airplanes, along with seven persons on the ground, were fatally injured. Nine persons on the ground were injured. Twenty-two dwellings were damaged or destroyed. The weather was clear, and the visibility was ten miles.

The NTSB determined that the probable cause of the accident was the failure of Flight 182’s pilots to comply with the provisions of a maintain-visual-separation clearance, including the requirement to inform the controller when they no longer had the other airplane in sight.

Library module: Boeing 727-214 and Cessna 172

Aeronaves de Mexico DC-9-32, Piper PA28-181, Cerritos, California, August 31, 1986

On August 31, 1986, about 1152 Pacific daylight time, Aeronaves de Mexico, S.A. Flight 498, a DC-9-32 with Mexican Registration XA-JED, and a Piper PA-28-181, N4891F, collided over Cerritos, California. Flight 498, a regularly scheduled passenger flight, was on an IFR flight plan from Tijuana, Mexico to Los Angeles International Airport, California, and was under radar control by the Los Angeles terminal radar control facility. The Piper airplane was proceeding from Torrance, California toward Big Bear, California, under VFR, and was not in radio contact with any air traffic control facility when the accident occurred.

The NTSB determined that the probable cause of the accident was the limitations of the air traffic control system to provide collision protection through air traffic control procedures and automated redundancy. Factors contributing to the accident were: (1) the inadvertent and unauthorized entry of the PA-28 into the Los Angeles Terminal Control Area, and (2) the limitations of the see-and-avoid concept to ensure traffic separation under the conditions of the conflict.

Library module: McDonnell-Douglas DC-9-32 and Piper PA28-181

Bashkirian Airlines Tupolev TU154M, DHL Boeing 757-200, Überlingen, Germany, July 1, 2002

On July 1, 2002 at 21:35:32 (UTC), a Tupolev TU154M passenger airplane flying as Bashkirian Airlines Flight 2937 from Moscow, Russia to Barcelona, Spain and a Boeing 757-23APF cargo airplane operating as DHL International Flight 611 from Bergamo, Italy to Brussels, Belgium experienced a mid-air collision over the town of Überlingen, Germany near Lake Constance. Both airplanes were destroyed. All aboard both airplanes were killed; 60 passengers and nine crew members on the passenger airplane, and the pilot and copilot on the cargo airplane. Both aircraft were equipped with TCAS II.

In this accident, investigators concluded that one carrier involved had trained crews that ATC instructions retained priority, and not to maneuver in contradiction to ATC instructions. Conversely, the other carrier involved in the accident had trained crews that TCAS instructions held priority, and to maneuver in accordance with a TCAS resolution advisory (RA), independent of any other ATC instructions. Investigators concluded that this conflict was a major contributor in this accident, as one of the airplanes involved followed ATC instructions, counter to a TCAS RA, and the other followed the RA, resulting in both aircraft remaining on a collision course.

Library module: Tupolev TU154M and Boeing 757-200

Cessna 208, Dudek Paragliders Solo 21, Fulshear, Texas, December 21, 2021

A Cessna 208B airplane collided with a powered paraglider during cruise flight at 5,000 feet mean sea level (msl) in Class E airspace. Based on video evidence, the powered paraglider operator impacted the Cessna’s right wing leading edge, outboard of the lift strut attachment point. The outboard ten feet of the Cessna’s right wing separated during the collision. The Cessna was equipped with a transponder and an ADS-B Out transmitter, which made the airplane visible to the air traffic control system. The operation of the powered paraglider in Class E airspace did not require two-way radio communication with air traffic control, the use of a transponder, or an ADS-B Out transmitter and therefore was not visible to air traffic control. Neither the Cessna nor the powered paraglider were equipped with ADS-B In technology, cockpit display of traffic information, or a traffic alerting system. After considering all the known variables, it is likely that the Cessna pilot did not see the powered paraglider with sufficient time to avoid the collision.

The NTSB attributed the accident to the limitations of the see-and-avoid concept as a method for self-separation of aircraft, which resulted in an inflight collision. Contributing to the accident was the absence of collision avoidance technology on both aircraft.

NTSB accident report: CEN22FA081

Back to top