Air Crash Investigations - Cracked Solder Joint - The Crash of Indonesia Air Asia Flight 8501

AIR CRASH INVESTIGATION

Over the last decades flying has become an everyday event, there is nothing special about it anymore. Safety has increased tremendously, but unfortunately accidents still happen. Every accident is a source for improvement. It is therefore essential that the precise cause or probable cause of accidents is as widely known as possible. It can not only take away fear for flying but it can also make passengers aware of unusual things during a flight and so play a role in preventing accidents. Air Crash Investigation Reports are published by official government entities and can in principle usually be down loaded from the websites of these entities. It is however not always easy, certainly not by foreign countries, to locate the report someone is looking for. Often the reports are accompanied by numerous extensive and very technical specifications and appendices and therefore not easy readable. In this series we have streamlined the reports of a number of important accidents in aviation without compromising in any way the content of the reports in order to make the issue at stake more easily accessible for a wider public.

An e-Book is different from a printed book. Especially tables, graphs, maps, foot and end notes and images are sometimes too complicated to be reproduced properly in an e-Book. For those who are interested in the full details of the story we refer to the printed edition of this publication.

Dirk J. Barreveld, editor.

CRACKED SOLDER JOINT: The Crash of Indonesia AirAsia Flight 8501

Copyright Page

CRACKED SOLDER JOINT: The Crash of Indonesia AirAsia Flight 8501

Final report of the Komite Nasional Keselamatan Transportasi (KNKT), Indonesia, concerning the crash of Indonesia AirAsia Flight 8501, an Airbus A320-216 registered as PK-AXC, Karimata Strait, Indonesia.

All Rights Reserved © 2015 Sagip Kabayan

[email protected]

Editor: Drs. Dirk J. Barreveld

No part of this book may be reproduced or transmitted in any form or by any means, graphic, electronic, or mechanical, including photocopying, recording, taping, or by any information storage retrieval system, without the permission in writing from the publisher.

Foundation Sagip Kabayan

ISBN: 978-1-329-76871-0

Table of Content

CRACKED SOLDER JOINT: The Crash of Indonesia AirAsia Flight 8501

Title Page

Copyright Page

Table of Contents

Synopsis

CHAPTER 1: FACTUAL INFORMATION

History of Flight

Injuries to Persons

Damage to Aircraft

Other Damage

Personnel Information

Aircraft Information

Flight Recorders

Wreckage and Impact Information

CHAPTER 2: TESTS AND RESEARCH

CHAPTER 3: ORGANIZATION AND MANAGEMENT INFORMATION

CHAPTER 4: ADDITIONAL INFORMATION

CHAPTER 5: ANALYSIS

CHAPTER 6: CONCLUSION

Findings

Contributing factors

CHAPTER 7: SAFETY ACTION

Safety Recommendations

APPENDIX: Startle Reflex

ENDNOTES

REFERENCES

ABBREVIATIONS AND DEFINITIONS

AIR CRASH INVESTIGATIONS

SYNOPSIS

On 28 December 2014 an Airbus A320-216 aircraft registered as PK-AXC was cruising at 32,000 feet on a flight from Juanda Airport, Surabaya, Indonesia to Changi Airport, Singapore with total occupants of 162 persons. The Pilot in Command (PIC) acted as Pilot Monitoring (PM) and the Second in Command (SIC) acted as Pilot Flying (PF).

The Flight Data Recorder (FDR) recorded that 4 master cautions activated following the failure of the Rudder Travel Limiter which triggered Electronic Centralized Aircraft Monitoring (ECAM) message of AUTO FLT RUD TRV LIM SYS. The crew performed the ECAM procedure on the first three master caution activations. After the 4th master caution, the FDR recorded different pilot action and the parameters showed similar signature to those on 25 December 2014 when the FAC CBs were pulled on the ground. This pilot action resulted on the 5th and 6th master caution activations which correspond respectively to ECAM message of AUTO FLT FAC 1 FAULT and AUTO FLT FAC 1+2 FAULT

Following two FAC fault, the autopilot and auto-thrust disengaged and the flight control reverted to Alternate Law which means the aircraft lost several protections available in Normal Law. The aircraft entered an upset condition and the stall warning activated until the end of recording.

Participating in the investigation of this accident were Australian ATSB, French BEA, Singapore AAIB and MOT Malaysia as accredited representatives.

The investigation concluded that contributing factors to this accident were:

- The cracking of a solder joint of both channel A and B resulted in loss of electrical continuity and led to RTLU failure.

- The existing maintenance data analysis led to unresolved repetitive faults occurring with shorter intervals. The same fault occurred 4 times during the flight.

- The flight crew action to the first 3 faults in accordance with the ECAM messages. Following the fourth fault, the FDR recorded different signatures that were similar to the FAC CB’s being reset resulting in electrical interruption to the FAC’s.

- The electrical interruption to the FAC caused the autopilot to disengage and the flight control logic to change from Normal Law to Alternate Law, the rudder deflecting 2° to the left resulting the aircraft rolling up to 54° angle of bank.

- Subsequent flight crew action leading to inability to control the aircraft in the Alternate Law resulted in the aircraft departing from the normal flight envelope and entering prolonged stall condition that was beyond the capability of the flight crew to recover.

Issues such as flight approval considered did not contribute to the accident and was not investigated. The FDR data did not show any indication of the weather condition affecting the aircraft.

Following this accident, the Indonesia Air Asia has performed several safety actions.

KNKT issued several recommendations to Indonesia Air Asia, Director General of Civil Aviation (DGCA), US Federal Aviation Administration and European Aviation Safety Administration (EASA) and Airbus.

CHAPTER 1: FACTUAL INFORMATION

History of Flight

On 28 December 2014, an Airbus A320-216 aircraft registered as PK-AXC was being operated by PT. Indonesia Air Asia on a scheduled flight from Juanda International Airport Surabaya, Indonesia to Changi International Airport, Singapore. The aircraft departed at 0535 LT (2235 UTC (1), 27 December 2014) and was cruising at 32,000 feet (FL320) via ATS (Air Traffic Services) route Mike 635 (M635).

The Pilot in Command (PIC) acted as Pilot Monitoring (PM) and the Second in Command (SIC) acted as Pilot Flying (PF).

The totals of 162 persons were on board this flight consisted of two pilots, four flight attendants and 156 passengers including one company engineer.

Picture 1. Indonesia Air Asia’s Airbus A320-216 aircraft registered as PK-AXC.

The sequence of events retrieved from both of Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) were as follows:

- 2231 UTC, the aircraft started to taxi.

- 2235 UTC, the aircraft took off.

- 2249 UTC, the flight reached cruising altitude of 32000 feet (Flight Level 320).

- At 2257 UTC, the PF asked for anti-ice ON and the flight attendant announced to the passengers to return to their seat and fasten the seat belt due to weather condition and possibility of turbulence.

- At 2300 UTC, the Electronic Centralized Aircraft Monitoring (ECAM) amber advisory AUTO FLT RUD TRV LIM 1 appeared. The PF asked ECAM action.

- At 2301 UTC, FDR recorded failure on both Rudder Travel Limiter Units and triggered a chime and master caution light. The ECAM message showed AUTO FLT RUD TRV LIM SYS (Auto Flight Rudder Travel Limiter System). The PIC read and performed the ECAM action of AUTO FLT RUD TRV LIM SYS to set Flight Augmentation Computer (FAC) 1 and 2 push-buttons on the overhead panel to OFF then to ON one by one. Both Rudder Travel Limiter Units returned to function normally.

- At 2304 UTC, the PM requested to the Ujung Pandang Upper West (2) controller to deviate 15 miles left of track for weather avoidance and was approved by the controller. The aircraft then flew on a heading of 310°.

- At 2306UTC, the SIC conducted cruise crew briefing including in the case of one engine inoperative or emergency descent and that Semarang Airport would be the alternate airport.

- At 2309 UTC, the FDR recorded the second failure on both Rudder Travel Limiter Units and triggered a chime and master caution light. The pilots repeated the ECAM action and both Rudder Travel Limiter Units returned to function normally.

- At 2311 UTC, the pilot contacted the Jakarta Upper Control (3) controller and informed that the flight turned to the left off the M635 to avoid weather. The information was acknowledged and identified on the radar screen by the Jakarta Radar controller. The Jakarta Radar controller instructed the pilot to report when clear of the weather.

- At 2312 UTC, the pilot requested for a higher level to FL 380 when possible and the Jakarta Radar controller asked the pilot to standby.

- At 2313:41 UTC, the single chime sounded and the amber ECAM message AUTO FLT RUD TRV LIM SYS was displayed. This was the third failure on both Rudder Travel Limiter Units on this flight. The pilots performed the ECAM actions and the system returned to function normally.

- At 2315:36 UTC, the fourth failure on both Rudder Travel Limiter Units and triggered ECAM message AUTO FLT RUD TRV LIM SYS, chime and master caution light.

- At 2316 UTC, the Jakarta Radar controller issued a clearance to the pilot to climb to FL 340 but was not replied by the pilot. The Jakarta Radar controller then called the pilot for several times but was not replied.

- At 2316:27 UTC, the fifth Master Caution which was triggered by FAC 1 FAULT followed by FDR signature of alteration (4) of parameters of components controlled by FAC 1 such as RTLU 1, Windshear Detection 1 and Rudder Travel Limiter Actuator 1.

- At 2316:44 UTC, the sixth Master Caution triggered by AUTO FLT FAC 1 + 2 FAULT and followed by FDR signature of alteration of parameters of components controlled by FAC 2 such as RTLU 2, Windshear Detection 2 and Rudder Travel Limiter Actuator 2. The Auto Pilot (A/P) and the Auto-thrust (A/THR) disengaged. Flight control law reverted from Normal Law to Alternate Law. The aircraft started to roll to the left up to 54° angle of bank.

Nine seconds after the autopilot disengaged, the right side-stick activated. The aircraft roll angle reduced to 9° left and then rolled back to 53° left. The input on the right side-stick was mostly pitch up and the aircraft climbed up to approximately 38,000 feet with a climb rate of up to 11,000 feet per minute.

- At 2317:18 UTC, the stall warning activated and at 2317:22 UTC stopped for 1 second then continued until the end of recording.

The first left side stick input was at 2317:03 UTC for 2 seconds and at 2317:15 UTC another input for 2 seconds, then since 2317:29 UTC the input continued until the end of the recording.

The right side stick input was mostly at maximum pitch up until the end of recording.

The lowest ISIS speed recorded was 55 knots. The ISIS speed recorded fluctuated at an average of 140 knots until the end of the recording.

- At 2317:41 UTC the aircraft reached the highest ISIS altitude of 38,500 feet and the largest roll angle of 104° to the left. The aircraft then lost altitude with a descent rate of up to 20,000 feet per minute.

- At approximately 29,000 feet the aircraft attitude was wings level with pitch and roll angles of approximately zero with the airspeed varied between 100 and 160 knots. The Angle of Attack (AOA) (5) was almost constant at approximately 40° up and the stall warning continued until the end of recording. The aircraft then lost altitude with an average rate of 12,000 feet per minute until the end of the recording.

Picture 2. The aircraft flight track.

- At 2318 UTC, the aircraft disappeared from the Jakarta Radar controller screen. The aircraft last position according to the Automatic Dependent Surveillance- Broadcasting (ADS-B) radar was on coordinate 3°36‟48.36S - 109°41‟50.47E and the aircraft altitude was approximately 24,000 feet.

The last data recorded by FDR was at 2320:35 UTC with ISIS airspeed of 132 kts, pitch 20° up, AOA 50° up, roll 8° to left, the rate of descent 8400 ft/minute and the radio altitude was 118 feet. No emergency message was transmitted by the crew.

Injuries to persons

The list of the persons on board including