What happened
On February 21, 2011, a Swearingen-SA 226 AT Metro II, registration EC-JCV, operated by Flightline, was conducting a positioning flight from Barcelona (LEBL) to Reus (LERS). While en route, the crew began experiencing progressive failures within the aircraft's electrical system, starting with communication difficulties and spreading to various avionics components, including the GPS and the co-pilot's artificial horizon.
As the electrical system became completely unusable, the crew declared a MAYDAY and requested an emergency landing at Barcelona. During the approach to runway 02, the crew observed another aircraft, an Airbus 320 (registration EC-KFI), which had just departed from runway 25L. The two aircraft crossed paths approximately 4 NM south of the field. While the lateral separation reached a minimum of 2.4 NM, the crew of EC-JCV maintained visual contact with the departing traffic throughout the encounter.
Due to an unconfirmed landing gear status caused by the electrical failure, the crew performed a missed approach at runway 02. They subsequently opted to land on runway 25L, which was configured for departures, to avoid an excessively tight turn. The crew successfully deployed the landing gear using the manual emergency pump and landed safely, though they noted difficulties with the aircraft's steering due to the lack of electrical power.
The investigation
The CIAIAC examined the electrical distribution architecture and the sequence of events involving air traffic control. The investigation focused on why the electrical system suffered a total collapse despite the redundancy built into the aircraft's design. Investigators also reviewed the coordination between the Control Center and the Tower regarding the authorization of departures during the emergency approach.
Findings
- The primary cause of the incident was a total failure of the aircraft's electrical system resulting from the blowing of both current limiters (acting as fuses) that supply power from the engine generators to the main bus.
- Maintenance inspections revealed that a terminal on the right engine generator was positioned too close to the generator's armature, which likely caused a short circuit that blew the right-side limiter.
- While the right limiter failure was linked to this physical proximity, the cause of the left limiter blowing—which should have been able to carry the full load—could not be determined because the aircraft was returned to service before a detailed inspection could be performed.
- The investigation noted that while the separation between the two aircraft was not critical, the authorization of a departure during an emergency approach created a potential risk.