The light aircraft that crash landed at Pondok Cabe Airport in South Tangerang, Banten, on Thursday, had flown without transponder or clear flight path, irritating air traffic controllers (ATC) who were busy directing many inbound flights into Jakarta, ATC recordings suggest.
The experimental single-seater aircraft, with registration number PKS-137, caught fire after the pilot, identified as Sugeng, attempted to land the "seemingly-unstable" plane, according to reports.
One and a half hours earlier, Sugeng became subject to criticism by Jakarta ATC who discovered him flying without proper plans.
According to ATC recordings available at www.liveatc.net, Sugeng, who departed from Palembang, South Sumatra, made initial contact with Jakarta ATC at 03.17 UTC or 10.17 a.m. Jakarta time.
But PKS-137, which at that time was flying around Bakauheni in the southern end of Sumatra, seemed to be unable to directly communicate with Jakarta ATC. Sugeng's communication was relayed by Garuda Indonesia flight GA 297 from Bengkulu enroute to Jakarta.
"Sierra 317, do you have a transponder onboard?" said one of the Garuda pilots to Sugeng, responding to the request from an air traffic controller who seemed not to have the ill-fated airplane on their radar screen.
"Negative, Sir," GA 297 said, relaying PKS-137's response.
Communications between PKS-137 and Jakarta ATC were relayed by GA-297 for only around two minutes. After that, the ATC seemed to have difficulties in confirming PKS-137's position and altitude.
"Sierra 317, report your position now," ATC called at 10.23 a.m., only to be met with silence.
At 10.28 a.m., ATC repeated the request five times and then repeated it again in Indonesian.
"Please use standard aviation terms to identify your location. Descend to 2,000 feet and report after reaching Merak," ATC said in a sharp tone, referring to a port city in western Banten.
ATC's communications with other aircraft at that time, according to the recordings, suggested that they were busy shifting the flow of incoming flights. Inbound traffic was redirected to the western airspace of Soekarno-Hatta International Airport because incoming traffic was diverted to land at runway 07 instead of 25.
This seemed to trigger concerns that the bigger jets would fly to the area where the transponderless PKS-317 was heading.
At 10.40 a.m., ATC called PKS-317 without any response.
"Please confirm leaving Merak?" ATC said. An answer believed to be from Sugeng was heard but was almost inaudible.
"Do you understand VFR corridor?" said ATC, referring to visual flight rules. "If you do, please use standard points," he continued in Indonesian.
"If you want to fly, have proper plans. Don't fly recklessly, use proper flight plans," ATC said angrily.
"I do have a flight plan, sir," Sugeng replied.
"Where is it? We don't have it," ATC responded.
Minutes later, PKS-317 was asked to radio ATC at Budiarto Airport in Curug, Banten. Jakarta ATC then transferred PKS-317 to Budiarto ATC which seemed to guide Sugeng to Pondok Cabe where it crash landed.