What happened
On December 7, 2016, a China Airlines Boeing 737-800, registration B-18605, was operating a scheduled flight from Palau's Roman International Airport to Taiwan's Taoyuan International Airport. While the aircraft was cruising at 38,000 feet over the Manila Flight Information Region, a passenger's smartphone began emitting smoke while connected to a power bank for charging.
Upon noticing the smoke, the passenger immediately removed the device from a seatback pocket and placed it on the floor. Cabin crew members responded promptly, utilizing a water fire extinguisher to suppress the smoke. Following the initial suppression, the crew monitored the device for approximately 10 minutes before transferring the smartphone into a container filled with cold water to ensure the temperature was stabilized. The flight crew inspected the cabin, confirmed the smoke had been extinguished, and determined that no further safety threats remained. The aircraft continued to its destination and landed safely at Taoyuan International Airport.
The investigation
The Taiwan Transportation Safety Board (TTSB) conducted an investigation involving the Civil Aviation Administration, the National Communications Commission, China Airlines, and Samsung Electronics. The investigation focused on the cause of the smoke and the effectiveness of the crew's response.
Technical analysis of the device, a Samsung Galaxy S6 edge, was performed by Underwriters Laboratories (UL). CT scans of the battery revealed a small hole approximately 1 mm in diameter at the site of an internal short circuit. While Samsung suggested the damage might have resulted from external impact or dropping the phone, UL investigators found no evidence of external mechanical damage or impact that would have caused such a failure. The investigation also reviewed the crew's training, the airline's lithium battery safety procedures, and the regulatory requirements for transporting portable electronic devices.
Findings
- The primary cause of the incident was an internal short circuit within the lithium-ion battery during the charging process, which generated intense heat within the enclosed space of the phone, leading to carbonization and smoke.
- The cabin crew demonstrated high proficiency in emergency procedures, successfully utilizing fire extinguishers and following established protocols for managing a lithium battery incident.
- The flight crew followed all company procedures for assessing the fire source and determined the flight could safely continue.
- The investigation found no issues regarding the aircraft's maintenance, airworthiness, or weight and balance.