CONTROLLED REST (CR) ON THE FLIGHT DECK

Copied straight from the CX Line Ops Web Site. This info doesn't seem to be referenced in Vol 2 Pt 2 or well disseminated.

General

  1. Sleep that occurs on the flight deck in an unintended manner is deemed to be subtle incapacitation.
  2. Sleep that occurs on the flight deck in a controlled manner is termed Controlled Rest (CR).
  3. CR is intended as a means of relieving excessive tiredness in flight. It does not absolve the crew member of their responsibility to be sufficiently rested before a flight.
  4. CR may only be conducted when specifically authorised by the Commander. This approval may not be assumed without being stated.
  5. CR is planned for an actual sleep period of maximum 40 minutes. Longer periods are not permitted due to the increased risk of sleep inertia and resulting prolonged grogginess.
  6. CR is intended as a means of addressing short term tiredness. It is not intended to be planned, nor is it part of a planned fatigue prevention schedule.
  7. CR cannot be used:
  8. to extend flight time duty limits,
  9. as an alternative to correct crew compliment, or
  10. as an alternative to proper rest periods / facilities.
  11. CR is an exceptional strategy and is available in addition to normal crew "bunk/seat" rest provided under the AFTLS.
  12. CR is an exceptional strategy to be used only when all other countermeasures have failed to prevent excessive tiredness which if not addressed may result in a degradation of safety. It is not a routine strategy to be employed whenever crew feel a bit tired.

Operational Considerations

  1. CR shall only be conducted during periods of low workload in cruise flight when weather conditions are benign and weather-related deviation is not required.
  2. Only one pilot, referred to as the ”resting pilot”, may use CR at any time. The operating pilot is referred to as the “non-resting pilot”. 
  3. During CR, the non-resting pilot shall perform the duties of PF and PM.
  4. In the event of any abnormal condition, the non resting pilot shall wake the resting pilot.
  5. A formal hand over of duties must be completed in accordance with Operations Manual procedures. 
  6. During CR, the non resting pilot cannot leave his/her seat for any reason, including physiological breaks.
  7. LNAV/NAV is the preferred lateral mode during CR. FMS manipulations must be kept to a minimum. 
  8. Altitude changes are not permitted during CR.
  9. Fuel balancing must not be undertaken during CR. Normal fuel transfer selections may be carried out.
  10. The non-resting pilot is permitted to wear a headset with the cockpit speaker volume turned down. 
  11. The resting pilot may use equipment such as eye masks, earplugs and blankets.
  12. The resting pilot must wear a seat belt when seated at the controls and move the seat aft to such a position that interference with the control is minimised.

Liaison with the Cabin Crew

During operations where cabin crew form part of the operating crew:

  1. The Commander must inform the ISM if CR is to be undertaken and the manner in which it is to be conducted.
  2. The Commander or senior pilot on the flight deck must liaise with the Cabin Crew before commencing CR.
  3. Cockpit access should be restricted whilst a flight crew member is resting.
  4. Drinks and meals should not be requested nor brought unsolicited to the flight deck for the non resting pilot during CR.
  5. The Cabin Crew must be asked to call the flight deck via the interphone system at approximately 20 minute intervals. 

Limitations

  1. CR shall not commence until after Top of Climb and will terminate at least 30 minutes before planned Top of Descent.
  2. Periods of CR will consist of :

a) 5 minutes preparation time,

b) a maximum of 40 minutes rest

c) 15 minutes recovery time.

  1. The non-resting pilot is not permitted additional personal comfort items other than those fitted to aircraft systems e.g. foot heater controls.
  2. Prior to the resumption of flight deck responsibilities a recovery period of up to 15 minutes, devoid of any flight duties or briefings, will be planned.
  3. In exceptional circumstances more than one period of CR is permitted per pilot.
  4. Consecutive periods of CR for any individual pilot are not permitted.

Completion

  1. The non-resting pilot is responsible for waking the resting pilot and briefing him/her on the progress of the flight in accordance with Operations Manual procedures.
  2. The use of alarms or timers can be used to assist with the conduct of the CR
  3. Recording of the use of CR is not required. Any difficulties or suggestions to improve the procedure should be reported on the CAR.

Annex A

CONTROLLED REST ON THE FLIGHT DECK

One way of managing unavoidable excessive tiredness inflight is through the use of Controlled Rest on the flight deck. This is commonly referred to as “cockpit napping” and involves the use of short naps by one pilot, during low workload periods of the cruise, whilst seated at the controls of the aircraft. The remaining pilot assumes the roles of PF and PM simultaneously and monitors the aircraft and its systems.

Proper rest and correct rostering practices are essential; Controlled Rest is not a means of deferring duty or extending a flight duty period. Controlled Rest is not intended to reduce sleep debt, rather it is an option should tiredness overcome an otherwise well-rested and prepared crew. Controlled rest is one more element in a fatigue management program and another line of defence to manage fatigue risks.

Controlled rest is in line with industry best practice. Many regulatory bodies currently endorse controlled rest, and the practice is a formal procedure in many airlines. The UK CAA have stated that "Naps have a beneficial effect on performance and may be the most effective countermeasure against fatigue at work".

Napping and Performance

The weight of scientific evidence supporting the performance benefits of napping under controlled circumstances is overwhelming. Controlled rest is an effective method of managing fatigue and tiredness on a short term basis and improving physiological alertness and performance, especially on long haul flights and flights that occur in periods of circadian low. 

The longer the period of the nap, the more beneficial its effects However, this must be balanced against the impacts of sleep inertia and the time available for napping. Naps of only 25 minutes can improve performance for hours afterwards.

Sleep Characteristics

Micro Sleeps

Sleep is a vital physiological function; sleepiness is the signal sent to indicate that the requirement for sleep has not been met. Without sufficient sleep, the human brain can instantly shift from wakefulness to sleep to meet this requirement. The human being has no control over these “micro sleeps” and they are independent of the individual’s willpower. No amount of training or conditioning can make an individual immune to sleepiness. Micro sleeps can vary in length from seconds to minutes. The human brain will command these micro sleeps even when it could be fatal, e.g. falling asleep at the wheel of a car, or on final approach in an aircraft.

Microsleeps are exacerbated during the period of circadian low (0000-0500) when circadian cycles prepare the body for sleep. 

Circadian Rhythm 

Circadian rhythm refers to the biological “clock” that determines, amongst other things, sleep patterns. A mechanism in the brain regulates physiological and behavioural functions based on a 24 hour clock. The body clock cannot adjust instantaneously when either work schedules are changed (i.e. the introduction of shift work or night work), or time zones are changed. It may require many days to adjust to a changed time pattern or overcome “jet lag”. The effects of this circadian de-synchronization are more marked with eastward travel than with westward travel as it is easier for the body to adapt to days being “stretched out” rather than compressed. 

The circadian clock re-synchronizes at the rate of approximately one to two hours of time zone change per day. To flight crew, this makes long layovers at outports of a significantly different time zone hazardous to their sleeping patterns. Continual disruption of sleeping patterns will result in a cumulative sleep debt, which in turn leads to fatigue. 

Fatigue

Fatigue decreases alertness and performance, increases errors, slows reactions and impacts on memory and decision making; all effects which have the potential to be fatal in the aviation environment. Fatigue is influenced by three factors:

    1. Cumulative sleep loss,
    2. Hours of continuous wakefulness, and
    3. Circadian time of day. 

These three factors represent both acute and chronic fatigue. Acute fatigue is commonly referred to as tiredness and is related primarily to the hours of continuous wakefulness and the circadian time of day. For example, most people will be tired after a long days work or most people are tired at 0300, regardless of how well rested they are. Chronic fatigue is related to cumulative sleep loss. Cumulative sleep loss is the result of sleeping less than the biological need of approximately 8 hours each day.

A fatigued pilot may attempt to counter fatigue by increased vigilance and activity but these effects will be short lived. If the biological requirement for sleep is present, micro sleeping will occur. 

Sleep Inertia

Sleep inertia is the unavoidable “grogginess” experienced after waking resulting in difficulty achieving full alertness and performance immediately after sleep. 

The degree of sleep inertia is correlated with; 

    1. the depth of the sleep, 
    2. the timing of the sleep and 
    3. the length of prior wakefulness. 

Deep, slow wave sleep (stage 4 sleep) is associated with greater sleep inertia. Longer sleep is often related to deeper sleep, thus longer sleep is associated with greater sleep inertia. Sleep inertia is also increased in someone with a long period of prior wakefulness (ie, a very tired person). Finally, naps taken during the first few hours of nocturnal sleep or during the circadian trough (0000-0500) result in more prolonged sleep inertia (due to the rapid onset of deep sleep).

Limiting naps to 45 minutes will minimise the amount of sleep inertia by minimising the chance of entering deep sleep. The effects of sleep inertia usually disappear within 15 minutes, and in less than 5 minutes in well-rested people. 

The negative effects of sleep inertia may be rapidly overcome in an emergency situations through the release of adrenaline. Thus if a pilot had to awaken quickly to deal with an emergency situation, the effects of sleep inertia might be overcome by adrenaline.

Sleep inertia is the small price to pay for the benefits of improved alertness later in the flight.

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