What happened
On February 6, 2013, an Airbus A340-313, registration CC-CQE, operated by LAN Airlines, was performing a scheduled international flight from Frankfurt to Santiago via Madrid. After departing Madrid-Barajas airport on runway 36L, the aircraft was climbing through 26,000 feet when the flight crew detected an odor similar to tear gas, followed quickly by the appearance of smoke in the cockpit.
The crew immediately donned oxygen masks, declared an emergency, and requested an immediate return to Madrid. The smoke was also confirmed to be present in the passenger cabin. During the subsequent descent, the aircraft's ECAM displayed an alert indicating a regulator fault in air conditioning pack 1, which placed the pack in bypass mode. This automatic reconfiguration isolated the air cycle machine, causing the smoke to dissipate.
Due to the necessity of an immediate return and the aircraft's configuration, the crew prepared for an overweight landing. The aircraft landed on runway 32R at 00:18 UTC. During the landing roll, the crew detected a brake odor, and the aircraft's brakes reached a temperature of 430 °C. Fire services accompanied the aircraft during taxiing to monitor the situation.
The investigation
The CIAIAC investigation focused on the source of the smoke and the management of the emergency. Investigators examined the air conditioning system and found that the failure of the air cycle machine in pack 1 was the source of the smoke. The smoke had spread through the ventilation ducts to both the flight and passenger compartments.
The investigation also reviewed the landing performance. The commander chose to perform a manual landing rather than an automated one, likely due to concerns regarding changing wind conditions. However, this manual approach resulted in a descent rate of 540 ft/min, exceeding the recommended limit of 360 ft/min for an overweight landing. The investigation also noted that the aircraft had been dispatched under the Minimum Equipment List (MEL) with a failure in the FCMC number 2, which contributed to the aircraft's overweight status.
Findings
- The primary cause of the incident was a failure of the air cycle machine in the number 1 air conditioning pack, which generated smoke that entered the cabin via the ventilation system.
- The crew's rapid response in using oxygen masks and declaring an emergency prevented injuries to the 244 passengers and 14 crew members.
- The automatic transition of the air conditioning system to bypass mode effectively isolated the faulty component and cleared the smoke.
- The decision to perform a manual landing led to a hard landing, characterized by a descent rate exceeding the structural recommendations for overweight operations.