The Aviation Safety Council （hereinafter ASC） releases final report on the investigation of a V Air flight ZV 252 air turn-back due to smoke and fire of a passenger carried power bank during cruising.

On May 6, 2016, a V Air A321-200 passenger airplane, flight number ZV 252, registration number B-22610, departed from Taoyuan International Airport （hereinafter Taoyuan Airport ）  to Tokyo Haneda International Airport to execute a scheduled passenger flight. The flight departed with 2 flight crew, 4 cabin crew and 163 passengers, totally 169 people on board. While this aircraft was cruising, a power bank which carried by a passenger could have had internal malfunction or defects before it was connected to this passenger's mobile phone for charging, causing combustion and resulted in the power bank to smoke and fire, and the flight crew members requested air turn-back to Taoyuan Airport.

According to the Republic of China Aviation Occurrence Investigation Act and referencing to the related content of Annex 13 to the Convention of International Civil Aviation Organization, the ASC is an independent agency responsible for the occurrence investigation.. The organizations or agencies been invited to join the investigation team included: Civil Aeronautics Administration of Ministry of Transportation and Communications, National Police Agency, Ministry of Interior and Bureau d'Enquêtes et d'Analyses of France.

Findings related to probable causes: The occurrence power bank could have had internal malfunction or defects before it was connected to a passenger's mobile phone for charging, causing combustion and resulted in the power bank to smoke and fire. Due to the circuit-protecting board and two battery cells were burned out, the exact causes for this malfunction could not be identified consequently.

Findings related to risks:

1. If a lithium-ion battery is located in an overheated environment, impacted from outside, overcharged, or if this battery has imperfection in its design or production, this battery's temperature will rise from chemical reactions of the battery discharging. Suppose the rising temperature from battery discharge further rise the temperature of this battery, a lithium-ion battery thermal runaway may be induced by the high temperature.
2. If this power bank carried by passenger has not been properly certified or it had been impacted upon somewhere, then charging or discharging battery by passengers during flight is prone to induce the battery cell thermal runaway as a result of exothermic chemical reaction during battery cell discharging.
3. In the twelve months prior to this occurrence, the Taoyuan Aviation Police Bureau, National Police Agency of Ministry of Interior, found out some 150,000 items of power bank or spare lithium battery with lithium-ion from checking baggage in Taoyuan Airport. This indicates that passengers neglected to pay attention to the regulation or they are not aware of such regulations requiring hand carry lithium-ion battery. There is room for improvement in terms of educating or informing passengers through publicity, or through check-in counters reminding the passengers.

Safety Recommendations

Recommendations to Civil Aeronautics Administration, Ministry of Transportation and Communications:

1. Evaluate the risks of passengers using lithium-ion battery power bank for charging or discharging during flight; continue to understand the international norms and possible actions of this issue; take timely revision of corresponding regulations of the Republic of China to reduce the potential risks.
2. Supervise national civil aviation transportation category airlines companies to enhance air safety education and publicity programs regarding the transportation of lithium-ion battery power bank and spare lithium battery that passengers should hand carry or through a carry-on luggage when boarding an airplane.

Full investigation report is available for download at ASC website: www.asc.gov.tw

Contact: Sherry Liu, Engineer
Tel: 89127388-330
Email: Sherry@asc.gov.tw