When deriving a problem, at any level, it is of the utmost importance that a structured procedure is followed and adhered to. These procedures are to ensure every possible aspect, cause and solution of the problem get considered and evaluated. Especially in the aerospace industry, where critical components are paramount to flight safety.
On the 12th of July 2013 at 1534 hrs, a lone Boeing 787-8 (ET-AOP) parked on Stand 592 caught fire at the rear end of the fuselage. The plane was parked at Heathrow Airport electrically unpowered and unoccupied by engineers, pilots and passengers. Despite there being no injuries or deaths, it was declared a serious incident by the AAIB. This determination initiated AAIB investigation procedures.
2. Objective of the Investigation
The objective of any aircraft investigation following the protocols of ICAO-Annex 13 (2016) is the ‘prevention of accidents and incidents’. The activity is ‘not to apportion blame or liability’. This statement is reiterated within regulation 4 of The Civil Aviation – Investigation of Air Accidents and Incidents Regulations (1996).
The initial step to any incident is containment. Containing the incident allows the investigators to understand the problem extent and limit it. The AAIB chief inspector, in exercise of his powers under the The Civil Aviation (1996) characterised the situation as a serious incident. The AAIB promptly gathered the aircraft information details including ‘aircraft type and registration, location, date and time of the occurrence, number of injuries and fatalities, particulars relating to the involvement of dangerous goods and a brief description of the circumstances’ i.e. the initial aircraft examination and history of the event. Manual of Aircraft Accident and Incident Investigation, Pt 1 , Chapter 2, Section 2.2. (2015)
Following ICAO-Annex 13 (2016), Chapter 4, The state of occurrence (The State in the territory of which an accident or incident occurs) issued a prompt awareness or ‘Notification’ statement to key stakeholders who are directly involved with the incident. I.e. the state registry and operator, in this instance Ethiopian Airlines (Aviation Safety Network, n.d.), the state of design (authority for design of aircraft) and manufacture (authority for the final assembly of an aircraft) represented by the NTSB, The TSBC (representative of a component manufacture) and ICAO were also notified. At this point of the investigation, the state of occurrence delegates stakeholders to participate in the investigation and are required to issue the AAIB with relevant information as defined in ICAO-Annex 13 (2016), Chapter 5. Note, the state of occurrence shall investigate a ‘serious incident when the aircraft is of a maximum mass of over 2.250 kg’. ICAO-Annex 13 (2016), Section 5.1.2.
Cross-functional expertise is an essential part of any investigation. Including a variety of process/industry experts introduces a vast depth of knowledge to aid the investigation. The investigation team identified that the most extensive heat damage occurred close to the crown, centred on the rear fuselage. This location coincides with the ELT and associated wiring system. (AAIB Bulletin S5/2013, p. 2). The ELT contained a set of Lithium-Manganese Dioxide (LiMnO2) battery’s, manufactured by a Honeywell supplier called Instrumar Ltd (AAIB Bulletin S4/2014, p. 2). These batteries allowed the ELT to operate in isolation. Hence it does not need power from an external source which explained how an unplugged, unpowered aircraft could ignite. A further brief analysis of the ELT showed indications of disruption to the battery cells; however, this was unclear at the initial stage. The TSBC, Honeywell and Instrumar Ltd conducted an escape analysis which identified that a total of 6,000 ELT units had been produced and installed on a wide range of aircrafts. (AAIB Bulletin S5/2013, p. 3).
This process resulted in the following containment actions or ‘Safety Recommendations’ being issued: 2013-016 & 2013-017. (AAIB Bulletin S5/2013, p. 3). These initial actions contain and limit any similar incidences from occurring, protecting people’s lives.
4. Responsibilities & Procedures
The AAIB has full independence in conducting the investigation, this includes unrestricted authority over its conduct. Investigations shall include:
1. ‘the gathering, recording and analysis of all relevant information on that accident or incident’;
The state of registry, operator, design and manufacture shall each appoint a reprehensive to participate it in the investigation. The state of registry is responsible for supplying all information regarding the aircrafts pilots, maintenance, destinations and distances travelled and all its encompassing history.
The state of design and manufacture is responsible for conducting an internal investigation to how this part escaped with the known defect. Honeywell a subsidiary of Boeing produced an NOE as per Boeing PO note U40. The NOE detailed the following:
• Affected processes and product numbers/names. I.e. the ELT.
• Description of the NC condition and the affected requirement reference.
• Quantities, dates, PO’ and destinations of delivered shipments.
• Suspect/affected serial numbers or dates codes, and aircraft line units when applicable.
Instrumar Ltd a Honeywell supplier gathered the information, Honeywell being a direct supplier to Boeing submitted the NOE.
2. ‘the protection of certain accident and incident investigation records’;
3. ‘the issuance of safety recommendations’;
4. ‘the determination of the causes and/or contributing factors’; and
5. ‘the completion of the Final Report’, as defined in the Manual of Aircraft Accident and Incident Investigation – Part IV (2003).
This report is the responsibility of the AAIB.
(ICAO-Annex 13, 2016) Section 5.4.
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