Balai Pendidikan dan Pelatihan Penerbangan Banyuwangi (Cessna 172 PK-BYK); Lombok International Airport, KNKT.17.11.33.04

On 21 November 2017, a Cessna 172S aircraft registered PK-BYK was being operated by Balai Pendidikan dan Pelatihan Penerbangan Banyuwangi (BP3B) on a cross country training flight from Blimbingsari airport (WADY), Banyuwangi to Sultan Muhammad Kaharuddin airport (WADS), Sumbawa Besar.

On board the PK-BYK were two student pilots. The Student Pilot 1 (SP1) acted as Pilot Flying (PF) and the Student Pilot 2 (SP2) acted as Pilot Monitoring (PM). Prior to departure there was no report or record of aircraft system malfunction.

The PK-BYK departed from Banyuwangi with intention to cruise at altitude of 7,000 feet and when approached point KUBU TAMBAHAN, the PK-BYK pilot requested to Bali approach controller to climb to altitude of 9,000 feet and was approved.

At the same day, an ATR72-600 aircraft registered PK-WHS was being operated by PT. Wings Abadi Airlines (Wings Air) as a scheduled passenger flight from Sumbawa to Lombok International Airport (WADL), Nusa Tenggara Barat with flight number WON1861. Prior to departure there was no report or record of aircraft system malfunction.

The WON1861 departed from Sumbawa with cruising altitude of 8,000 feet. On board the aircraft were two pilots, two flight attendants and 62 passengers, the Pilot in Command (PIC) acted as PM and the Second in Command (SIC) acted as PF.

When the PK-BYK aircraft approaching point NAMP ISLAND, the PK-BYK PF saw an ATR72-600 aircraft flew through clouds from the opposite direction with aircraft nose slightly up. The PK-BYK PF assumed that the ATR72-600 aircraft was on climbing and then the PF decided to descend with intention to avoid the ATR72-600 aircraft.

The separation of both aircraft reduced to below minima when the PK-BYK pilot left altitude 9,000 feet at 01:31:40 UTC, the distance of both aircraft was 4.7 Nm and continued reducing.

Both flights continued their flight to the destination safely. The aircraft was undamaged and no one injured in this occurrence.

The investigation determined that the aircraft and radio communication serviceability were not issues in this occurrence and the investigation concluded the contributing factor was the assumption of ATR72-600 on climbing and not aware of the right of way rules resulted in the PK-BYK pilot decided to descend aircraft for traffic avoidance.

The KNKT had been informed corrective action taken by the AirNav Indonesia and BP3B responding to the KNKT safety recommendation in the preliminary report. The KNKT acknowledged the corrective actions and considered relevant to address the safety issue described in this report. Therefore, KNKT did not issue safety recommendation in this report.