The detrimental effects of drugs and alcohol on cognitive abilities are well documented. International research suggests the likelihood and severity of accidents increase if people responsible for performing safety-critical tasks use drugs or alcohol. In the New Zealand air, rail, and marine accidents investigated by the Transport Accident Investigation Commission, the consumption of alcohol or use of other performance impairing substances recurs as a contributing factor or a potential impediment to survival. Following first publication of this Watchlist item, legislative change is now underway to require all commercial aviation and maritime operators to have drug and alcohol plans and to give regulators testing powers. However more can still, and should, be done.
What is the problem?
Judgement, decision-making, and reaction time can all be affected by the use of drugs or alcohol. The use of performance-impairing substances by persons performing safety critical tasks in a transport environment is a significant risk. The Ministry of Transport supports zero tolerance of operator impairment; however, industry arrangements are uneven across the sectors and more could be done to manage this risk.
What is the solution?
- set maximum limits for alcohol
- prohibit people operating aircraft, vessels or rail vehicles if they are substance impaired
- require operators to implement drug and alcohol detection and deterrence regimes, including random testing
- prescribe post-occurrence testing requirements for drugs and alcohol.
The detrimental effects of drugs and alcohol on cognitive abilities have been described and documented by researchers in the transport sector. Australian Transport Safety Bureau research describes how alcohol ‘impairs almost all forms of cognitive function, such as information processing, decision-making, attention and reasoning’ (Newman, 2004a, p.1).[i] Such impairment detrimentally affects the performance of any demanding task.
Cannabis can also adversely affect behaviour, cognitive function and psychomotor performance; ‘complex tasks … are particularly sensitive to the performance-impairing effects of cannabis’ (Newman, 2004b, p.1).[ii] In the case of a pilot, for example, flying skills deteriorate, and the pilot makes an increasing number of errors. Pilots are often unaware of their reduced performance.
The risk of accidents increases if people responsible for performing tasks critical to the safe operation of aircraft, vessels or rail vehicles use drugs or alcohol. The Australian research states ‘many studies have shown a significant proportion of aircraft accidents associated with alcohol use’ (Newman, 2004a, p.1); similarly, a US report states, ‘numerous studies have shown that alcohol use increases both the likelihood and severity of boating accidents’ (Lawrence, Miller & Maxim, 2006, p.1).[iii]
The consumption of alcohol, or use of other performance-impairing substances, features repeatedly in accidents investigated by the Commission. Since the beginning of 2014, we have investigated twelve occurrences where persons performing safety-critical roles in the operation of aircraft, vessels, or rail vehicles have tested positive for performance-impairing substances (one of these occurrences involved prescription medicines).[iv] Forty-two people died in these accidents, including the eleven killed in the hot-air ballooning accident in Carterton, one of New Zealand’s worst aviation disasters.
The Commission has made several recommendations about setting maximum allowable limits for performance impairing substances for people in safety-critical roles, including those in charge of recreational craft; and providing for testing of such levels. Limits should be appropriate to the mode, and adequately tested for; and they should reflect the goal of zero tolerance to impairment. These measures are in line with the alcohol and drug testing, including random testing, that is accepted practice in road transport, as well as in other modes in other jurisdictions.
As a result of our recommendations, new measures are being introduced requiring commercial aviation and maritime operators to have drug and alcohol management plans. In addition, the aviation and maritime regulators (the Civil Aviation Authority and Maritime New Zealand) will be given the power to undertake non-notified alcohol and drug testing. This can include random testing, good cause testing and post incident testing. No changes have been made to the recreational boating sector.
When investigating an accident, the Commission cannot require survivors, including those in safety-critical roles, to be tested for performance-impairing substances. This makes it difficult to assess the contribution, if any, of performance-impairing substances to an accident or incident. The power of regulators to undertake non-notified alcohol and drug testing in the commercial aviation and maritime sectors will go some way to providing a solution to this difficulty.
The Commission will continue to monitor the incidence of accidents featuring alcohol or drug impairment, and to seek a regulatory environment that supports a zero tolerance for impairment in safety critical transport roles.
[i] Newman, D. G. (2004a) Alcohol and Human Performance from an Aviation Perspective: A Review. Research report from the Australian Transport Safety Bureau.
[ii] Newman, D. G. (2004b) Cannabis and its Effects on Pilot performance and Flight Safety: A Review. Research report from the Australian Transport Safety Bureau.
[iii] Lawrence, B. A. Miller, T. R., and Maxim (2006) Recent Research on Recreational Boating Accidents and the Contribution of Boating Under the Influence: Summary of Results [.pdf]. Report by the Pacific Institute for Research and Evaluation sponsored by the United States Coast Guard.
- Report 12-001: Hot-air balloon collision with power lines and in-flight fire, near Carterton, 7 January 2012. Open Safety Recommendation 012/13
- Report 15-101: Pedestrian fatality, Morningside Drive pedestrian level crossing, West Auckland, 29 January 2015
- Report 13-103: Passenger train collisions with Melling Station stop block, 15 April 2013 and 27 May 2014
- Report 12-104: Train 723 overran limit of track warrant Parikawa, Main North line, 1 August 2012
- Report 12-201: Fishing vessel Easy Rider, capsize and foundering, Foveaux Strait, 15 March 2012
- Report 11-103: Track workers nearly struck by passenger train near Paekakariki, North Island Main Trunk, 25 August 2011. Open Safety Recommendation 007/13
- Report 10-009: Walter Fletcher FU24, ZK-EUF, loss of control on take-off and impact with terrain, Fox Glacier aerodrome, South Westland, 4 September 2010. Open Safety Recommendation 011/12
- Report 09-201: collision: private jet-boat/private watercraft, Kawarau River, Queenstown, 5 January 2009. Open Safety Recommendation 005/11
- Report 06-204: fishing vessel Kotuku, capsized, Foveaux Strait, 13 May 2006
- Report 05-003: Piper PA34-200T Seneca II, ZK-FMW, controlled flight into terrain, 8 km north-east of Taupo Aerodrome, 2 February 2005
- Report 04-212: fishing vessel Iron Maiden, foundered off Pandora Bank, Northland, 16 August 2004
- First published January 2015 and updated October 2016. This issue’s updates: references to new inquiries; information on new measures and continuing policy work intended to help reduce the risk of drug and alcohol impairment. This update was consulted with: Ministry of Transport, Civil Aviation Authority, New Zealand Transport Agency, Maritime New Zealand.
- Updated: October 2016. Updated content: references to new inquiries; information on new measures and continuing policy work intended to help reduce the risk of drug and alcohol impairment. Consulted with: Ministry of Transport, Civil Aviation Authority, New Zealand Transport Agency, Maritime New Zealand.
- Updated: August 2017. Updated content: references to newly released inquiries; reference to adequate testing of performance-impairing substances. Consulted with: Ministry of Transport, Civil Aviation Authority, New Zealand Transport Agency, Maritime New Zealand.