Synopsis
On 26 February 2018 at 18:04 UTC, a Cirrus SF50 Vision Jet, registration N3AD, sustained a serious incident during landing at Nuuk Airport (BGGH), Greenland. The aircraft, on a delivery flight from the United States to Europe, departed Iqaluit, Canada, at 16:27 UTC and had an uneventful flight until the landing roll. The pilot experienced a loss of left brake pressure, causing the aircraft to veer right and eventually exit the runway into a snowbank. There were no injuries.
Factual Information
History of the Flight
The aircraft was operating under Instrument Flight Rules (IFR) on a non-commercial relocation delivery flight. Upon initial contact with Nuuk Aerodrome Flight Information Service (AFIS), the pilot received weather information including wind 140° magnetic at 2 knots, visibility more than 10 km, clear sky, temperature -9°C, and runway condition 10% covered with 1 mm compact snow, braking action good. During descent the pilot requested a visual approach to runway 05. Just before landing, wind at the threshold was reported as 150° magnetic at 5 knots for runway 05. During the landing roll, the pilot applied both toe-brake pedals but shortly thereafter experienced a total loss of brake pressure on the left pedal. The aircraft veered right. The pilot released pressure on both pedals and then instructed the passenger in the right seat to apply both pedals; that passenger also noted left brake pressure loss. The pilot regained directional control and attempted to stop using only the right brake, but the aircraft continued veering right and departed the side of the runway, coming to rest in a snowbank. The pilot declared a MAYDAY, and AFIS alerted fire and rescue services.
Injuries and Damage
No injuries were sustained by the pilot or the single passenger. The aircraft suffered minor damage to the nose wheel door, left main wheel door, and wing profile fairings due to impact with the snowbank. No other damage occurred.
Personnel Information
The pilot, a 44-year-old male, held a US Temporary Airman Certificate issued on 22 February 2018, based on a German Airline Transport Pilot License (ATPL) from 24 June 2013. His medical certificate (Class 1) was valid until 20 May 2018 with no limitations. His total flight experience was 14,000 hours; experience on the Cirrus SF50 type was not stated. The aircraft had accumulated 5.3 total airframe hours as of 14 February 2018 and held a valid standard airworthiness certificate.
Aircraft Information
The aircraft was a Cirrus SF50 Vision Jet, serial number 0034, manufactured in 2018, powered by a Williams International FJ33-5A engine. The brake system included a schematic and tube routing detailed in the bulletin appendices. The Airplane Flight Manual (AFM) contains abnormal procedures for landing with failed brakes.
Analysis
The Danish Accident Investigation Board (AIB) concluded that the serious incident resulted from insufficient torqueing of a brake tube fitting, which led to leakage of hydraulic brake fluid. This leakage caused a partial brake failure, specifically loss of left brake pressure, resulting in a runway side excursion. The event occurred in daylight under visual meteorological conditions (VMC).
Probable Cause
The probable cause of the serious incident was insufficient torqueing of a brake tube fitting leading to leakage of hydraulic brake fluid and a consequential partial brake failure resulting in a runway side excursion.