Aircraft struck terrain after encountering poor visibility at low-level

On February 3, 2021, a Cessna 172 aircraft crashed into a hillside during a flight from Cromwell to Gore. The pilot did not survive the accident.

The Civil Aviation Authority (CAA) investigation found that the probable cause of the accident was the pilot flying in reduced visibility conditions and inadvertently impacting terrain, with several human and environmental factors contributing to the accident.

“The key lessons from this accident are to ensure thorough flight planning is conducted, especially when flying through areas that are remote, and that a timely decision is made to divert or turn back if required,” said Deputy Chief Executive Aviation Safety David Harrison.

The pilot's pre-flight weather assessment likely did not consider the forecast weather along the route. The route and decision to continue led the aircraft into deteriorating weather with limited diversion options. The aircraft configuration and airspeed were not suitable for the reduced visibility conditions and low-level flight.

A moving weather front meant conditions were suitable at the destination but not along the route flown. Orographic cloud formation due to the local terrain and weather likely blocked the pilot's escape route and led to the accident.

“New Zealand Civil Aviation rules set the minimum safe standard for aviation and we rely on participants to be vigilant and thorough every time they take flight – it only takes one poor decision for tragedy to strike, as in this case, which sadly could’ve been avoided,” said Mr. Harrison.

The CAA has produced several educational publications to raise awareness of the risks associated with flying into deteriorating conditions, and there are several free aviation weather forecast services available.

Media contact phone 027 763 0000 or email media@caa.govt.nz

Safety lessons (p3 of report)

• Thorough pre-flight planning, including checking forecast weather conditions along the route using appropriate sources, selecting the most suitable route and assessing alternative routes in case the weather deteriorates, enables a pilot to anticipate and make timely decisions to divert or turn back.
• Regularly practicing mountain flying, low flying, and flying in the reduced visibility configuration with an instructor, is important to reinforce initial training and to keep flying skills current for pilots. These skills give a pilot more options and time to make good decisions when faced with adverse weather conditions.
• Biennial flight reviews (BFR) are an opportunity to practise and improve skills in non-normal operations, and to simulate bad weather and en route diversions or decision making. It is important for private aircraft owners who are based away from a flight training environment to ensure they are flying with an instructor regularly to maintain skill currency.
• Pilots should always have an escape route when flying in valleys, and preferably more than one, so that if weather conditions change rapidly and a turn back is required, a safe route out of valleys, through passes or saddles is available to them. Pilots should not enter a valley if their only known escape route is not certain to remain open.

Safety Investigation Report – Cessna 172G ZK-COM [PDF 1.6 MB]

CAA safety resources: Education