FC5280 / FC5281 / FC5282

18hr awake ‘rule’

FC5280 Report text: Recent communication from our Chief Pilot was aimed to ‘clarify’ the 18hr awake guidance we have in our manuals. This has been triggered by multiple pilots using this guidance to report as unable to perform a duty. The tone of this email is very clearly pressure being applied from above on pilots to operate the schedule they have very poorly designed from the outset. The biggest culprits are deep-night duties and our extended 2-sector duties which have the highest cancellation rates.

Standbys are being rostered to start at 1400L where call-outs are being made for pilots to operate deep-night duties. These are typically scheduled to land back to base at 0500L to 0700L. The inference from the company by rostering like this is that the crew member should be adjusting their sleep periods to move towards these late duties in their own time on their own days off. A typical 3 days off would allow the circadian rhythm to only move about 4 hrs, which would still put a deep-night duty at the extreme end of the company’s own 18hr limit. A 1400L standby on day 1 after days off is fine but the expectation on the part of the company must be that a crew member can only operate a reasonable duty. A finish by 2am from this example would be reasonable as this could assume something like an 8am natural wake up as circadian rhythms predicate – a 7am finish is unreasonable.

We have hundreds of new pilots in the company who are going to be very easily influenced by someone like the Chief Pilot and will now feel pressure to operate beyond what they should safely do. [Airline] seem to have forgotten their own responsibility to create safe rosters and put far too much onus on individual crew members.

FC5281 Report text: [Airline] have recently picked up several night slots operating from 6-9pm and finishing 6-9am. Whilst if rostered this can be managed, a significant number of them are uncrewed on roster publication leading to Standby call outs. When on Home Standby, it is reasonable to be awake at 9am, regardless of the Standby start time. This subsequently leads to a period awake of roughly 24 hours and when quoting to crewing the 18hrs awake/reduction in FDP they’re extremely reluctant to change anything.

We have recently had an email from our Chief Pilot applying lots of commercial pressure to be asleep until our Standby starts in order to complete these duties. Quite frankly I think it’s utterly ridiculous and stems from the company not adequately crewing the operation.

FC5282 Report text: Our Chief Pilot issued an email reminder on the use of the 18hr awake rule when called from Standby. This is mainly related I believe to the overnight flights that [Airline] have been operating since last summer. These have proved difficult for the company to crew as they are effectively trying to operate package holiday flights while the organisation is setup to operate a scheduled service. This has resulted in them often being crewed by staff who have been called out from Standby duties that are not really aligned with the night flights.

The latest email guidance from the company is that the 18hrs should only refer to the sum of the Standby period added to the FDP and that crew should be managing their rest appropriate to the Standby period. This seems to match the CAA guidance but surely it is madness to expect someone who has, for example, a 1415L Standby start embedded in a standard roster of lates (that might involve reporting early afternoon and off duty around midnight) to stay asleep until 1415L in case they get called to do a late duty?

There are already plenty of stories doing the rounds of crews really struggling to operate safely when bringing a plane back into [Airport] in the middle of the morning rush and now we have some added commercial pressure to continue to operate when it’s not really sensible. Doesn’t look like a good recipe to me!

Company Chief Pilot email

[CAP1265] guidance material recognizes that awake time is difficult to control for an operator and consequently creates an expectation on the design of our procedure. The UK CAA have also confirmed that 18hrs awake time is covered in the guidance material of the regulation and as such there is no ‘rule’ in the eyes of the regulator but [Airline] needs to have processes in place to ensure they consider this guidance covered within the FTL regulation.

Our OM-A has a number of protections built in to ensure our standby procedures in combination with FDP manages this limitation as described below:

In order to ensure that crew members are not awake for more than 18 hours, [Airline] limits the maximum duration of Home Standby to 8 hours and crew members may request hotel accommodation at home base at the Company’s expense after having completed a duty of 14 hours or more.

Nevertheless, it is the responsibility of the crew member to manage their rest and sleep opportunities during pre-duty rest periods and while on standby to enable them to carry out an FDP. If a crew member is called from home standby to undertake an FDP and has reason to believe they may not be sufficiently rested as they will have been awake for 18 hours or more when the duty finishes, the individual needs to consider whether they are fit to operate either part of the duty or the full duty based on whether they are sufficiently rested and fit to fly. In the event that the crew member is insufficiently rested to complete the full advised FDP, the individual should explain this to the Crewing Officer who will consider whether there are other options available. If the crew member operates an FDP shorter than that originally advised, or no alternative FDP is available although the crew member is fit to fly, a paper Commander’s Discretion Report should be completed in respect of “Discretion to Reduce a Flight Duty Period”. In such circumstances the limitation on individual crew members (see Section 7.2) will not apply. In the event that the crew member states they are insufficiently rested to perform any FDP a Fatigue Report Form should be completed in the normal manner, within 72 hours of the conversation. The FRF will be managed through the current safety system.

[Airline] will monitor duty length resulting from combination of standby and FDP and will identify duties over 16 hours as part of the FRM compliance oversight.

The majority of the 18 hour awake calls from the crew don’t come from their standby and FDP combination being 18 hours, it is crew stating they have been up since X and with the off duty of their flight they will have been awake for 18 hours. We are also seeing crews quoting the 18hrs rule when a scheduled duty is delayed but within FDP limits.

There is currently no intention to amend our procedures but we would ask you to ensure you manage your rest and nap opportunities in pre-duty rest periods and while on standby to enable them to carry out an FDP.

CAA Comment

The 18-hour awake guidance is guidance and was never intended as a tool to manage crews on the day of operation. The intent was to avoid operators planning 12+ hrs on standby and not relating the standby period to operational needs using the 18-hour awake as a metric for planning purposes. The fact that operators have shorter standby periods staggered over the day meets the requirements of the 18-hour awake guidance.

The first key issue is whether being ‘awake’ is counted from the start of Standby or when actually awake. The guidance for 18hr maximum ‘awake’ calculation for time on standby plus FDP is somewhat vague in this respect and simply comments that the combination of standby and FDP should not lead to more than 18hrs awake time. The company email, says that they limit Home Standby to a maximum of 8hrs so their expectation is that there are at least 10hrs of FDP time available if someone were called at the end of the standby period and they were awake at the beginning of their Standby.  It is this awake time that is in contention given that people may well have been awake before their Standby starts depending on their previous roster/life activity. The human body cannot simply be switched on and off and so it is the impact of that pre-standby ‘awake’ time that needs to be considered but is not factored into regulations.

This issue is akin to acclimatisation in circadian rhythm terms – the start of a standby period ought perhaps to be looked at in terms of effective time zone transitions from the previous duty so that an assessment of human performance can be made; that sounds complicated and involved but there may be ways of thinking of it in these terms to provide a firmer basis for rostering based on what might be expected of the human body. A table might be produced for those transitioning to standby from a previous rostered duty that reduces the ‘standby and FDP’ awake time allowed depending on the temporal relationship between the previous duty’s end and the Standby duty’s start.

CHIRP considers that it is not unreasonable for companies to expect crews to condition themselves in terms of rest on days off before duties so that they effectively ‘acclimatise’ to the duty ahead, but there are limits as to what can be expected in normal day-to-day operations. To be fair to the company, the email does state that: “In the event that the crew member is insufficiently rested to complete the full advised FDP, the individual should explain this to the Crewing Officer who will consider whether there are other options available.” The bottom-line is that crews need to be sufficiently rested for the potential duty they might be asked to do and this might have to involve sleeping at odd hours during days off so that they are rested sufficiently to do the 18hr ‘standby plus FDP’ period (albeit the 18hr awake time is purely guidance).  If crews are not sufficiently rested when called from Standby then they are correct to report as fatigued and the company email highlights that: “In the event that the crew member states they are insufficiently rested to perform any FDP a Fatigue Report Form should be completed in the normal manner, within 72 hours of the conversation.”

The corollary question from all of this is, “Are days off really days free from duty if people are expected to condition themselves for subsequent ‘work days’ given that this might involve serious disruption to their ‘day off’?” but that is part and parcel of being a professional pilot to some extent.

Associated regulations:

CS FTL.1.225 Standby

(b) Standby other than airport standby:

(2) The operator’s standby procedures are designed to ensure that the combination of standby and FDP do not lead to more than 18 hours awake time;

GM1 CS FTL.1.225 (b)(2) Standby


Scientific research shows that continuous awake in excess of 18 hours can reduce the alertness and should be avoided.


How do you apply CS FTL.1.225 (b)(2)? What is the definition of “awake time”?

CS FTL.1.225 (b)(2)

EASA have not provided a definition of “awake time”. A straight forward mathematical answer is not possible. There is no expectation on the operator to verify how long a crew member has been awake.

However, the operator has to design its standby procedures in a way that the duty in combination with the FDP will manage this limitation. The operator can only manage what it has control of (the standby and FDP). The operator’s procedures need to demonstrate how the awake time is managed. It is reasonable for the operator to expect a crew member to manage rest and nap opportunities in pre- duty rest periods and while on standby to enable them to carry out an FDP. The expectation is on the design of the procedure.