Two passenger planes missed each other in the Kenyan airspace by a minute last week, averting what would have been one of the world's worst aviation accidents.
The near-collision, at Naivasha, 100 kilometres west of Nairobi, was prevented when the pilot of one of the planes — upon receiving a warning from the inflight traffic collision system — made a sudden climb to avoid the oncoming flight.
The incident, involving an Ethiopian Airlines plane and an Italian leisure airline flight, has become a major point of discussion in aviation circles, and has led to a blame game between Kenya and Ethiopia.
On Wednesday August 29, the Ethiopian Airlines flight number ET858, a Boeing 737-800, registration number ET-ASJ left Johannesburg for Addis Ababa at 2100 hours. Its flight time was five hours, 12 minutes cruising at a calibrated altitude of 37,000 feet.
On the same day at 18:00 hours, an Italian leisure airline Neos Boeing 767-306R flight number NOS252, registration I-NDOF had left the Italian city of Verona heading to Zanzibar. Its flight time was eight hours before it made its first landing in Zanzibar.
At 00:49 hours, both aircraft were in Kenyan airspace, at the same altitude, with the Italian aircraft having entered from the Ethiopian airspace, while the Ethiopian Airlines from the Tanzania airspace. They were flying towards each other. SEE INFOGRAPHIC
The Traffic Collision Avoidance System is built in planes to monitor the airspace around an aircraft for other aircraft equipped with an equivalent active transponder. The system, which is independent of air traffic control, warns pilots of the presence of other aircraft.
The TCAS Resolution Advisory alerted the Ethiopian airline crew about the impending mid-air collision and the pilot climbed to 38,000 feet in just one minute (at 00:50 hrs). He maintained the altitude for five minutes, avoiding a collision.
Kenya's air traffic controllers seem to be blaming the incident on a strike by Ethiopian air traffic controllers.
“The Italian airliner approached and entered the Kenyan airspace from the Westside using 370L but it wasn’t informed by the Ethiopian air control that an ET flight was also using the same altitude East side as it crossed over Kenya heading to Addis. This was a serious breach of safety,” a source in the Kenyan aviation sector told The EastAfrican.
The source said the Ethiopian air traffic controllers had began their strike four days prior to the near-crash, and failed to honour the co-ordination procedures agreed between Nairobi and Addis Ababa on air traffic navigation and management.
The day after the near mishap, the Kenya Air Traffic Controllers’ Association warned that flights going into and out of the Addis Ababa airspace were not safe.
“We have seen some eastbound flights coming in with westbound flight levels while some westbound flights have eastbound levels, increasing chances of serious air misses,” the association president Peter Ang’awa said, adding that they were concerned about serious safety issues they have noted in the past few days after their Ethiopian counterparts went on strike.
The Ethiopian Air traffic controllers had for the second time in three months, downed their tools on August 25, demanding a salary rise, better working conditions and overtime pay. In April, the same airport staff went on strike resulting in dozens of flight delays.
Mr Ang’awa said the Ethiopian traffic controllers did not provide proper standard separation in last week’s incident.
“We saw flights from Addis Ababa calling the Nairobi Control without prior estimates, with the possibility of creating serious air-misses with known traffic at the transfer point given that they were entering our airspace with wrong levels. This was the issue with the ET and Neos, which both maintained FL360 with no prior co-ordination and no estimates from Addis Ababa control. Were it not for the TCAS, the story would have been different,” he said.
However, a pilot with several years' experience, told The EastAfrican that if the planes were in Kenyan airspace, then they were under Kenya's Air Traffic Control (ATC), which should have guided them accordingly and warned them that they were going to cross each other’s flight path.
"Collison is difficult in this age. Throughout the flight you are under ATC, and you're given ‘separation’ so that you don't collide with another plane," he said. “In a situation like last week's, the pilot must react immediately to save the passengers and crew. The passengers would feel the sudden jerk, but at such a point it is not a matter of comfort. It is about avoiding a collision."
The Kenya Civil Aviation Authority Director General Captain Gilbert Kibe declined to comment on the incident, only stating that everything was now in order.
“As it is, things are now okay and I will not comment on this,” Capt Kibe said on the sidelines of the Africa Civil Air Navigation Services Organisation conference in Mombasa.
Mid last week, the Ethiopian Civil Aviation Authority (ECAA) rejected the Kenyan air controller’s claim, saying its control centre is manned by capable air traffic controllers, adding that the approach and aerodrome positions within its airspace are also manned with professionals possessing all the qualifications.
“We reject the false and baseless statements circulated by the Kenyan Air Traffickers Controllers Association. Our Area Control Centre in Addis Ababa is being manned by adequate number of well-trained, highly capable instructors and professionals with the necessary ratings and validations in accordance with International Civil Aviation Organisation Annex 1 provisions. To date, we have not received any complaints by any airlines operating to/from Ethiopia or over flying our airspace,” ECAA said in a statement, adding that all its air traffic control activities and communications are recorded and protected, and can be verified if need be.
Ethiopia has since arrested nine Ethiopian air traffic controllers alleged to be leading the work boycott, with the Police deputy commissioner Tekolla Ayfokiru saying the nine workers were preventing international flights from landing at the Bole International Airport, the country’s busiest hub.
“Some of the employees engaged in the illegal strike are returning to work. The remaining should submit a letter of apology and return to their work. They have until Tuesday (September 4),” the head of ECAA, Col Wesenyelew Hunegnaw said, adding that a salary review was ongoing.
A pilot’s view
Throughout the flight the pilot is under the Air Traffic Control. The control gives you a squawk — a four letter code- — which you feed into your transponder.
The ATC will see you on the radar and is able to monitor your speed and height. As the pilot leaves the airspace of one country (Flight Information Region), he or she is handed over to the ATC of the next country.
Under the American Federal Aviation Authority Aviation regulations, large passenger aircraft are required to be at least five kilometres apart horizontally or 1,000 feet vertically.
Much like on our roads, there are airways to be followed and each has reporting points. The pilot must communicate on radio until he reaches a different country’s airspace, during which he is handed over by the Air Traffic Control of the new airspace.