Recommendations for the Work Hours of UK Aircraft Maintenance Personnel Simon Folkard D.Sc. Chair:ICOH Shiftwork Committee President:Working Time Society Director:Body Rhythms and Shiftwork Centre University of Wales Swansea

Remit from CAA Assess the work hours of Aircraft Maintenance Personnel and produce recommendations for “good practice”

4 Phases: 1. Survey Licensed Aircraft Maintenance Engineers. 2. Survey Employers & Contractors (mainly as check) 3. Review Literature on Safety and Fatigue. 4. Produce Recommendations for “Good Practice”.

Survey of A.M. Engineers. Posted to all UK Licensed Engineers returns (from c. 8000, i.e. 27.6%, 2093 analysed). Questions included: 1. All aspects of Work Hours (Scheduled, Normal, Minimum & Maximum). 2. Sleep lengths 3. “Risk” (sleepiness, mistakes, confidence) 4. Physical health 5. Interference/Advantages

Shift Systems in Operation >100 different shift systems. 5 main categories: Rotating shifts involving nights (32.5%) Rotating shifts without nights (30.2%) Permanent nights (9.1%) Permanent afternoons (1.4%) Permanent mornings/days (26.7%)

Hours Per Week

Length of Night Shift

Hours before a Break

No. Successive Work Days

Sleep Duration on Different Shifts

Sleep Before Morning Shifts

Review of Safety Literature Injuries and Accidents Can be “pin-pointed” in time. Can be related to specific features of shift systems. But Need large numbers, and Often the a priori risk is not constant!

Studies Across Three Shifts Author(s)IndustryLocationMeasureNumber Wanat (1962)Coal MiningUndergndInjuries3699 Wanat (1962)Coal MiningSurfaceInjuries1328 Quaas & Tunsch (1972) Metallurgic Plant N/AInjuries1577 Quaas & Tunsch (1972) Metallurgic Plant N/AAccidents688 Levin et al. (1985)ManufacturingN/AInjuries119 L. Smith et al (1994)EngineeringSite 1Injuries2461 L. Smith et al (1994)EngineeringSite 2Injuries2139 Wharf (1995)Coal Mining“Industrial”Injuriesc.1970 Totalc.13981

Risk Across Three Shifts

Studies Over the Night Shift Author(s)IndustryMeasureNumber (8 hours) Vernon (1923)MunitionsAccidents666 Adams et al (1981)Coal MiningInjuries829 Ong et al (1987)Steel MillInjuries150 Wagner (1988)Iron MiningAccidents775 L. Smith et al (1994)EngineeringInjuries902 Åkerstedt (1995)All OccupationsInjuriesc Wharf (1995)Coal MiningAccidents777 Macdonald et al (1997)Steel ManufacturingInjuries774 L. Smith et al. (1997)EngineeringInjuries657 Tucker (2000)EngineeringAccidents274 Totalc. 8304

Risk Over the Night Shift

Studies Over Successive Nights Author(s)IndustryMeasureNumber (4 Nights) Quaas & Tunsch (1972)Metallurgic PlantAccidents261 Vinogradova et al. (1975)DockersAccidents272 Wagner (1988)Iron MiningAccidents442 L. Smith et al. (1994)EngineeringInjuries1686 L. Smith et al. (1997)EngineeringInjuries842 Tucker (2000)EngineeringAccidents286 Oginski et al (2000)Steel MillInjuries63 Total3852

Risk Over Successive Nights

Studies Over Hours on Duty Author(s)DataMeasureTotal Number Akerstedt (1995)Sweden (1990/1)Lost time Injuries (1+ days) 160,000 Haenecke et al (1998)Germany (1994)Lost time Injuries (>3 days) 1,200,000+ Nachreiner et al (2000)Germany (1994-7)Fatal Injuries2,000+ Folkard (1997)*Various Transport Operations Accidents or SPADs N/A Total>1,362,000 * Based on several published studies

Risk over hours on duty

How Can We Minimise Safety Problems? 1. Select and/or counsel individuals 2. Educate individuals regarding problems and coping strategies 3. Reset the clock (light/melatonin) 4. Improve shift systems

Recommendations for “Good Practice” Need to: 1. Minimise the build up of fatigue over periods of work. 2. Maximise the dissipation of fatigue over periods of rest. 3. Minimise sleep problems and circadian disruption

Daily Limits 1.No scheduled shift should exceed 12 hours. 2.No shift should be extended beyond a total of 13 hours by overtime. 3.A minimum rest period of 11 hours should be allowed between the end of shift and the beginning of the next, and this should not be compromised by overtime.

Rest Breaks 4.A maximum of fours hours work before a break. 5.A minimum break period of ten minutes plus five minutes for each hour worked since the start of the work period or the last break. N.B. “there is some evidence to suggest that frequent short breaks are more beneficial than less frequent longer ones”

Weekly Limits 6.Scheduled work hours should not exceed 48 hours in any period of seven successive days. 7.Total work, including overtime, should not exceed 60 hours or seven successive work days before a period of rest days. 8.A period of rest days should include a minimum of two successive rest days continuous with the 11 hours off between shifts (i.e. a minimum of 59 hours off). This limit should not be compromised by overtime.

Annual Limits 9.Wherever possible, a total of 28 days annual leave should be aimed for and this should not be reduced to less than 21 days leave by overtime.

Limits on Night Shifts 10.A span of successive night shifts involving 12 or more hours of work should be limited to 6 for shifts of up to 8 hours long, 4 for shifts of 8.1 to 10 hours long, and 2 for shifts of 10.1 hours or longer. These limits should not be exceeded by overtime. 11.A span of night shifts should be immediately followed by a minimum of two successive rest days continuous with the 11 hours off between shifts (i.e. a minimum of 59 hours off) and this should be increased to three successive rest days (i.e. 83 hours off) if the preceding span of night shifts exceeds three or 36 hours of work. These limits should not be compromised by overtime. 12.The finish time of the night shift should not be later than 08:00.

Limits on Morning/Day Shifts 13.A morning or day shift should not be scheduled to start before 06:00, and wherever possible should be delayed to start between 07:00 and 08: A span of successive morning or day shifts that start before 07:00 should be limited to four, immediately following which there should be a minimum of two successive rest days continuous with the 11 hours off between shifts (i.e. a minimum of 59 hours off). This limit should not be compromised by overtime.

Days notice of Schedule 15.Wherever possible aircraft maintenance engineers should be given at least 28 days notice of their work schedule.

Further Recommendations for “Good Practice” (abbreviated) 16.Employers of aircraft maintenance personnel should consider developing “risk management systems”. 17.Educational programmes should be developed to draw attention to the objective trends in risk. 18.Aircraft maintenance personnel should be required to report for duty adequately rested. 19.Aircraft maintenance personnel should be discouraged or prevented from working for other organisations on their rest days.

Conclusions: Shiftwork can result in reduced safety (and increased fatigue). Shift systems should: Minimise the build up of fatigue Maximise the dissipation of fatigue Minimise sleep & circadian disruption Employers should develop “Risk Management Programmes”.