JAKARTA (THE JAKARTA POST/ASIA NEWS NETWORK) - Indonesia's air traffic controllers have warned of the risk of aircraft collisions and accidents unless their workload is eased, as the country's main Soekarno-Hatta International Airport struggles to cope with the huge expansion in air travel.

The Indonesian Air Traffic Controllers Association (IATCA) complained on Wednesday about the decision by state-run air navigation company AirNav to regularly allow 84 take-offs and landings an hour at the airport, as occurred recently during the Hari Raya Puasa exodus last month.

"By allowing this, the chance of an accident will increase and air traffic controllers will be the ones who are blamed," Mr Andre Budi, deputy chairman of IATCA Jakarta, said.

The group said the 84 hourly take-offs and landings were beyond the airport's handling capacity, and claimed it also violates Transportation Ministerial Instruction No. 8/2016, which caps the use of the airport's runways at 74 aircraft per hour and four irregular flights for emergencies.

IATCA's revelations came amid a string of reports of near-collisions, with the latest occurring only last month.

AirNav confirmed that two aircraft came close to colliding with each other on the runway of Soekarno-Hatta on June 18, a week before the June 25 Muslim festival which is called Idul Fitri.

Air traffic controllers had to order a Garuda flight to abort its landing as there was still a Sriwijaya Air aircraft on the runway that had earlier aborted its take-off.

Last year, two Lion Air planes collided on the ground at Soekarno-Hatta airport. Fortunately, no injuries reported.

SAFETY RECORD

Soekarno-Hatta airport, located in Tangerang, Banten province, is one of the busiest airports in South-east Asia, serving more than 55 million passengers last year, with 1,200 flights per day.

Indonesia's aviation market has grown by double digits in the past 10 years following the appearance of several low-cost carriers that have made air transportation more affordable.

Indonesia received poor marks in a 2014 safety audit by the United Nations aviation agency due to insufficient staffing.

Mr Andre said that most air traffic controllers would require more training to handle the high traffic that had begun to build up since 10 days before the Idul Fitri holidays and which had yet to recede, even though the peak travel season had passed.

Mr Andre suspected the soaring traffic may be a result of airlines bending regulations to add more flights beyond their approved slots.

IATCA has lodged complaints with AirNav and the Directorate General for Aviation at the Transportation Ministry.

"We want the government to return to the pattern of 72 aircraft per hour to prevent accidents," Mr Andre said.

IATCA also suggested that the government provide more training to air traffic personnel and improve airport infrastructure.

In response, AirNav corporate secretary Didiet K.S. Radityo said there was no violation of regulations as the Transportation Ministry had updated its instruction in No. 16/2017, allowing 81 take-offs and landings effective from July 20.

"The increase was to accommodate demand from the airlines in line with the growing economy and tourism," he said.

"Eighty-one aircraft per hour is the new maximum standard. But on average, the load usually stands at 74 to 75 per hour," he said.

Mr Didiet said the recent ministerial instruction had been adjusted to better serve flight schedules and to avoid congestion at the airport by distributing the flights away from the busiest times.

The instruction is also based on input from the Transportation Ministry's coordinating unit for flights slots, state airport operator Angkasa Pura, and a consulting firm for London's Heathrow Airport.

The adjustment to the traffic, Mr Didiet said, was not only designed to tackle the problem at Soekarno-Hatta airport, but also at the destination airports, as well as for ground-handling facilities.

In a statement, the Transportation Ministry said the maximum flight frequency at the airport had been increased to 81 take-offs and landings per hour to accommodate increasing demand from aviation companies.

"Demand has been growing. Therefore, flight frequency has had to be increased," the ministry's director general for aviation, Mr Agus Santoso, said in a media statement on Thursday.

Mr Agus added that as the main hub of domestic flights, Soekarno-Hatta Airport's capacity had to be in line with the fast growth in tourism and economic activities.

"At Heathrow Airport, runways can handle 100 aircraft per hour. As long as procedures and regulations are obeyed, it will be safe," he said, adding that AirNav had done a study on flight safety.

In 2012, when air traffic was managed by Angkasa Pura, frequency was only 52 aircraft per hour. Since the job was taken over by AirNav, the maximum flight frequency has continued to be increased.

Last year, maximum flight frequency was increased to 76, and under Transportation Instruction No. 16/2017, maximal flight frequency was increased to 81 this year.

Indonesia witnessed its last major civilian aircraft accident in 2014 when an AirAsia flight went down in the Java Sea, claiming the lives of all 162 people on board.