History of the Flight
The aircraft, a Bombardier CRJ1000 (CL-600-2E25) registered EC-LPG, operated by Air Nostrum, departed from Pamplona Airport (LEPP) at 06:13 on 1 February 2015 after spending the night there. Snow had been falling throughout the night and was still intermittent at the time of departure. Runway snow plows had been working to clear the runway. The aircraft was deiced and then taxied on the apron, which had standing slush. It took off normally from runway 33, which also had slush. The flight to Adolfo Suárez Madrid-Barajas Airport (LEMD) was uneventful. Upon landing at Madrid-Barajas, the crew felt vibrations originating from the main landing gear, which they interpreted as a tire blowout. They informed air traffic control and requested a nearby parking stand. After parking, the crew observed flat spots on the outboard tires of both main landing gear.
Injuries to Persons
There were 2 flight crew, 2 flight attendants, and 63 passengers on board. No injuries were reported.
Damage to Aircraft
The outboard tires on the left main landing gear (wheel #1) and the right main landing gear (wheel #4) exhibited flat spots. No other damage was noted.
Causes/Contributing Factors
The investigation determined that the flat spots on the #1 and #4 wheel tires were caused by the wheels locking during taxi in slush and snow at Pamplona. The wheel lock occurred due to the application of the parking brake while taxiing. This application resulted from an inadequate interpretation of the aircraft manufacturer’s instructions, which were not clear and could lead to confusion.
Aircraft Information
The aircraft was a Bombardier CRJ1000 (CL-600-2E25), serial number not specified, registered EC-LPG. It was operated by Air Nostrum. The landing gear system includes carbon brakes and an anti-skid system. The investigation focused on the wheel locking mechanism and brake application during ground operations in contaminated conditions.