The German accident investigation agency BFU released a preliminary report on a cargo smoke incident on an ATR-72 passenger flight on August 18.
The Czech Airlines ATR-72-500 airplane, took off from Prague at 07:32 as flight OK534, bound for Frankfurt, Germany. During the descent towards Frankfurt, the flight crew smelled smoke. After asking the cabin crew to investigate the source, the Centralized Crew Alerting System (CCAS) displayed “ELEC SMOKE” and “FWD SMOKE” warnings. The flight crew then donned their oxygen masks and declared an emergency.
Meanwhile the cabin crew had opened the doors to cargo area in front of the passenger cabin. With the help of passengers they removed luggage in an attempt to locate the source of the smell. After locating the bag, it was brought into the galley where it was cut open. A halon-fire-extinguisher was then used. For the remainder of the flight one cabin crew member remained in the galley to keep an eye on the bag.
At 08:32, while preparing for an ILS approach to runway 25L at Frankfurt Airport, the crew cancelled the emergency. A safe landing was carried out at 08:44. The aircraft taxied to the stand.
An investigation revealed that there had not been an open fire. However, there had been a significant heat development inside the bag.
The source turned out to be one of two 1-liter glass bottles with screw cap, both of which were wrapped with adhesive tape. One of the bottles was broken, leaking the contents into the suitcase. The bottle contained hair bleaching liquid. Why and how this liquid started generating heat is till under investigation.