Why do midair aircraft collisions occur and how can they be avoided?

A midair collision between a civilian passenger aircraft and a military helicopter over Washington DC, is said to be among the worst aviation accidents in recent history, killing 67 people.

Though mid-air collisions are rare, they are disastrous. A mid-air collision, according to aviation experts, is an accident in which two or more aircrafts come into unplanned contact during flight.

This could happen due to miscommunication, error in navigation, deviations from flight plans, lack of situational awareness and non-availability of onboard collision-avoidance systems.

Most collisions tend to take place in the vicinity of airports, where several aircrafts are spaced more closely and, during ascent and descent phases of flight involving frequent course alterations and change in altitude. Additionally, there have been instances of collision between aircrafts while taxiing on the apron or runways.

Besides this, there are “near miss” instances. These occur when two aircrafts come dangerously close to each other in flight, but manage to avoid hitting each other. The reasons for a near miss also include miscommunication, navigation error and poor situational awareness.

Collisions between military aircraft also take place, especially during formation flying. Fighter aircrafts can collide while practising dogfights or close combat manoeuvres, or during aerobatics, where the aircraft are only a few feet apart.

Collisions between military and civilian aircraft and between aircraft and drones have also been reported in the past.

The history of manned powered flight began in 1903 with the Wright brothers’ Flyer-I and it was in October 1910 that the first recorded midair collision took place in Milan, Italy during an international aviation meet.

A Frenchman, René Thomas, flying the Antoinette IV monoplane, collided with British Army Captain Bertram Dickson flying a Farman III biplane. Both pilots survived, but Dickson’s severe injuries prevented him from flying again.

According to aviation records, the first fatal collision occurred over La Brayelle Airfield in France in June 1912. Captain Marcel Dubois and Lieutenant Albert Peignan, both of the French Army, lost their lives after crashing into each other in early-morning haze.

Among the earliest known midair collisions involving civilian passengers was in April 1922 over Picardie in France involving British and French biplanes flying in foggy conditions at a height of just 492 feet.

A French Farman F-60 with two crew members and three passengers was flying from Paris to Croydon, while a British de Havilland DH-18A with two pilots ferrying mail was on its way from Croydon to Paris. All seven people perished.

The first aerial accident between a military and a civilian aircraft was reported in April 1929 when a Ford 5-AT-B Trimotor belonging to Maddux Airlines collided with a US Army Air Corps Boeing PW-9D at a height of 2,000 feet over San Diego in California, killing six people.

In 2024, over 30 major aircraft accidents were reported across the globe, including, crashes, inflight emergencies like fire, airframe damage and technical failures.

This included collisions such as an A350-900 of the Japan Airlines colliding on the runway with a Dash 8-Q300 operated by the Japan Coast Guard at Haneda Airport in Tokyo, and a Safarilink Aviation’s Dash 8 colliding with a Cessna 172M of a local flying school over Nairobi National Park in Africa soon after take-off.

India too has experienced midair collisions in its airspace. The most notable has been the incident over Charkhi Dadri, about 100 km west of Delhi. This occurred in November 1996, when a Saudi Airlines Boeing 747 enroute from Delhi to Dhahran crashed into an IL-76 of Kazakhstan Airlines.

All 349 people on board both planes were killed, making it the world’s deadliest mid-air collision and the deadliest aviation accident ever in India.

In February 2019, while practising for Aero India at Bengaluru, two Indian Air Force Hawk trainers from the Surya Kiran aerobatic team collided and crashed. The three pilots onboard ejected, with one, a Wing Commander, succumbing to his injuries.

The aircrafts involved in the latest accident over the US are a Bombardier CRJ700 regional jet manufactured by Canada with a passenger capacity of up to 78, and a US Army’s Sikorsky UH-60 Black Hawk, medium-lift utility helicopter that can carry 12 troops or 4,000 kg cargo.

Incidentally, the Indian Navy is procuring 24 SH-60 Sea Hawk helicopters, the Black Hawk’s naval variant, some of which have already been inducted into service.

Latest reports state that the flight data recorders and cockpit voice recorders of the ill-fated aircraft have been recovered. This would assist the investigating agencies to determine the cause of the collision.

Guarding against midair collision is standard part of pilots’ training and currency ratings in the civilian as well as military domains, with automated systems as well as visual references, physical protocols and cockpit procedures in place. Airspace in high density flying areas is closely monitored and strictly controlled.

The International Civil Aviation Organisation requires all aircraft with a maximum take-off mass of over 5,700 kg or capacity for more than 19 passengers to be equipped with a Traffic Alert and Collision Avoidance System (TCAS).

This monitors the airspace around an aircraft, for other aircrafts, equipped with a corresponding active transponder, independent of air traffic control and warns the aircrew of the presence of other transponder-equipped aircraft in the vicinity.

In addition to transponders, all aircraft while moving are also required to switch on navigation and warning lights that reveal their position. However, there may be instances when a military aircraft may operate with its transponders and lights switched-off to maintain operational secrecy.

Advanced navigational aids and communication systems, including satellite-based links, automation and state-of-the-art air traffic management services introduced over the past years have vastly improved accuracy in guiding aircraft and enabling them to maintain the correct flight level and compass bearing, helping, reduce the probability of error.

Aviation regulatory bodies and international agencies also constantly monitor operational as safety aspects and issue advisories and directives to mitigate vulnerabilities, review operating procedures or incorporate new technologies. Operators also have their own training regimens and educational programmes for cockpit crew and air traffic controllers in this regard.