Created Saturday, Mar 20th 2021 08:43Z, last updated Monday, May 3rd 2021 10:51Z
A Trigana Boeing 737-400 freighter, registration PK-YSF performing a freight flight from Jakarta Halim to Makassar (Indonesia) with 4 crew, was climbing out of Halim's runway 24 at 10:53L (03:53Z) when the crew stopped the climb at about 3000 feet due to the failure of the right hand engine. The crew entered a hold while attempting to correct the problem and subsequently returned to Halim airport for a landing on runway 24 at about 11:28L (04:28Z) about 35 minutes after departure. Following touchdown the right main gear collapsed and the aircraft skidded on the runway on left main gear, nose gear and right engine pod, during the last stages of the roll out the aircraft veered right off the runway and came to a stop with all gear collapsed. There were no injuries, the aircraft sustained substantial damage.
On May 3rd 2021 Indonesia's KNKT released their preliminary report summarizing the sequence of events:
On board in this flight was two pilots, one engineer and one Flight Operation Officer (FOO). According to the weight and balance sheet, the flight carried 16,672 kgs of general cargo and the take-off weight was 60,695 kgs (133,835 lbs). The Pilot in Command (PIC) acted as Pilot Flying (PF) and the Second in Command (SIC) acted as Pilot Monitoring (PM).
At 1051 LT, the aircraft departed Runway 24 of Halim and about two minutes later, the PM reported to the controller that the right engine failed and requested to return.
The aircraft approached landing with one engine inoperative and configured with flap 15 for landing, with the aircraft weight was about 131,000 lbs.
At 1126 LT, the aircraft touched down with 1.79 G vertically and -0.54 G laterally then shortly the right main landing gear failed. The aircraft stopped on the left runway shoulder about 2,200 meters from the beginning Runway 24 and all landing gears collapsed. No one injured in this accident. The aircraft substantially damage.
In a more detailed factual presentation of the sequence of events the KNKT stated following the engine failure the aircraft returned to Halim with one engine inoperative. The KNKT does not mention any problems with the gear extension, states the aircraft performed an ILS approach to runway 24 and concludes the factual chapter:
At 1125 LT, the PM reported to the controller that the Runway was in sight. The controller advised that the wind was from 060° at velocity of 6 knots, QNH 1,007 mbs and issued landing clearance.
The aircraft touched down on the touchdown zone and shortly after, both wheels of the right main landing gear detached. The controller noticed spark appeared from the aircraft and pressed the crash bell.
At 1127 LT, the controller informed pilots of the other aircraft that the runway blocked by the landing aircraft and identified fire on one of the engines. Few seconds later, the PM called the controller whether any fire and was replied by the controller that fire was visible on the left side of the aircraft.
The KNKT describes the damage: "The aircraft was substantially damaged. All three landing gears collapsed. Both engines mounting broken. Two tires and one brake assembly of the right main landing gear were detached while the left main landing gear wheels remained intact until the aircraft stopped."
The captain (34, ATPL, 6,228 hours total, 5,208 hours on type) was pilot flying, the first officer (22, CPL, 1,255 hours total, 1,084 hours on type) was pilot monitoring.
Explaining the FDR data the KNKT stated that both engines operated at 93% N1 until the aircraft reached 145 KIAS, then the right hand engine accelerted to 94% N1, EGT increased to 921 degrees C and two seconds later reduced to 54% N1, EGT decreased to 910 degrees C. 6 seconds after the right hand engine accelerated and 4 seconds after it dropped to 54% N1 the aircraft became airborne. About 8 minutes after becoming airborne the right hand engine reduced to 12% N1 and the fuel flow reduced to 10lbs/hour, the PACK switch was subsequently turned off.
The KNKT describes the tracks on the runway:
The first tire mark was found about 580 meters from the beginning Runway 24 and identified as the mark of the right main wheels, then followed by the tire mark of the left main wheels. All tire marks indicated zigzag movement of the wheels. The zigzag tire marks of the right main wheels ended about 380 meters and continued by zigzag scratch on runway, followed by paint marks. The zigzag tire marks of the left main wheels and the paint marks continued until the aircraft travelled off runway pavement.
One tire of the right main landing gear was found on the right side of the Runway 24, near the tower building after impacted to two cars that were parked. The other wheel was found on the left side of the Runway 24, after impacted to Airport Rescue and Fire Fighting (ARFF) fence. One of the brake assembly of the right main landing gear was found on the left side of the Runway 24, near the wind sock.
A0694/21 NOTAMR A0693/21
A) WIHH B) 2103200840 C) 2103201000 EST
E) RWY 06/24 CLSD DUE TO BLOCKED BY ACFT
A) WIHH B) 2103200500 C) 2103200900
E) RWY 06/24 CLSD DUE TO BLOCKED BY ACFT