Video embedded from YouTube on 16 August 2012
Alcohol is a major concern for aviation as it can cause serious incidents. Alcohol impairs performance and takes away anxiety and inhibitions (Robson, 20083). This can be fun in a social context, however can have serious implications if brought onto the flight deck or other safety sensitive roles where good performance is essential (Hawkins, 19932).
Although this list is by no means comprehensive, in most countries it is illegal to:
- Fly an aircraft and consume alcohol
- Fly with a blood alcohol content (BAC) of more than 40mg/100ml
- Fly within 8 hours of consuming alcohol
Prevalence in General Aviation
An early study by Harper and Albers (19641) stated that 35.4% of general aviation (GA) pilots involved in fatal accidents showed BACs that were measurable enough to impair performance. However, later studies revealed that this figure could be due to putrefaction (causing higher alcohol levels) as this was not considered during this study (Modell & Mountz, 1990; Cook, 1997). Later studies have more modest revelations of roughly 10 – 30% of GA pilots in fatal crashes showing measurable BACs, only half of which were above legal limits (Modell & Mountz, 1990).
Effects of Alcohol
The table below, adapted out of Campell & Bagshaw (2002) shows the general effects of alcohol at different BACs (by general I am referring to the fact they represent thresholds for everyone, not just pilots).
|30mg/100ml||Increases chance of having an accident|
|50mg/100ml||Impairment of judgement|
|200mg/100ml||Double vision accompanied by memory loss|
|400mg/100ml||Loss of consciousness|
|Table 1: the general effects of alcohol upon the human body at varying BACs|
Based on several studies into the effects of drinking and flying, Cook (1997) compiled a set of piloting tasks that were affected at different BACs:
- Trouble with terrain separation
- Impaired performance during aircraft descent
- Impaired performance when turning (angular acceleration)
- Impaired performance in dim lighting
- Worsened impairments of what is in the above category
- Inability to manage heavy workloads
- Cannot track radio signals properly
- Cannot track targets properly
- Inability to effectively follow movements instructed by air traffic control
- Inability to configure flight controls properly
- Inefficient at coordinating the flight (ie navigation, monitoring instruments)
- Inability to perceive other traffic, effecting capability of avoiding other aircraft
- Inability to respond quick enough to environmental cues such as flight controls (stick and foot pedals)
- 3 dimensional coordination
- Poor short term memory
- Slowed reaction times
- Impaired performance at higher gravitational forces (5 g)
- Progressively worsened impairment of everything in the above categories
- Impaired oculovestibular functions (poor interaction between vision and balance)
- Impaired performance at moderate gravitational forces (3 g)
It is clear from these tables that although we might afford such impairments in the above table when we are on the ground, the impairments caused by alcohol unto flightdeck performance (as shown above) are greater and potentially more catastrophic. The same concept applies to all safety sensitive roles (eg air traffic control).
Want to know more?
- The Effects of Alcohol on the Human Body
- For a more in-depth understanding of how alcohol can impair flight performance it is recommended that you go to this link and familiarise yourself with some specific alcohol related conditions that can affect flight safety.