Crewing by Numbers

The area within crew scheduling that has benefited most from computerisation has been the crew roster build process. This has dramatically reduced the number of staff required to produce crew rosters. (Istock)

Ray Brain, who spent 38 years working in all disciplines of crewing, manpower/training planning, roster build and day-to-day crew control with some of the world’s largest carriers, explains the ‘black art’ of manpower management for airlines.

The area within crew scheduling that has benefited most from computerisation has been the crew roster build process. This has dramatically reduced the number of staff required to produce crew rosters. (Istock)

How many staff, often defined in airline parlance as either pilots, resources, forward, tech or flight crew, do I need to operate a commercial schedule?  Unless the airline concerned is a freight-only operation, the same applies to cabin crew/flight attendants,
That is the question we need to answer before we can even start to build a crew roster and of course, getting the answer wrong will have significant consequences.  Too few crew members will lead to an unstable roster that will eventually impact the flying programme, while too many can be an expensive financial burden on the airline.
An old saying among crew planners was: “I can work out crew numbers on the back of a cigarette packet,” and, yes, this still basically holds true for smaller airline operations.  First, simply define the number of absent days (those days that a crew are not available to fly the schedule), over a period of 365 days.  This will include mandatory rest days, plus those for annual leave (vacation), together with assumed sickness rates, plus periods for training, office and whatever other ground duties are deemed necessary by the company.  The final number of days that a crew member can work over a seven-day period averages out at around 4.2 per week.
Ad-hoc charter companies may just decide to hire a fixed number of crew per aircraft, but for the purposes of this article we shall just concentrate on airlines with a known aircraft schedule.
Carriers with much larger aircraft fleets will inevitably use Manpower Planning Tool (MPT) computer software to vastly reduce the number of ‘man’ hours that would otherwise be required.  The choice to be made here will be financially driven: do you want to buy or lease an already proven ‘off the shelf’ system from a specialised software company, or employ the staff required to develop an in-house system using your company’s IT resources?
Crew numbers derived by using MPT systems can also be calculated by dividing the total average block hour – defined as the time between the moments when the aircraft moves from its departure gate through to when its brakes are applied at its destination gate – workload for a given month per crew into aircraft planned block hour utilisation.
Pairings, Trips and Patterns (PTP)
So-called crew pairings, trips and patterns, all mean the same thing: the stringing together of a sequence of flights to form a flight crew member’s working day.  The details of the aircraft’s flying schedule originate from the airline’s commercial department and are supplied to the crew planners/rostering team so that they can produce legal crew PTPs.  Strict adherence to the legally binding Flight Time Limitations (FTL) scheme published by the local authority, together with so-called ‘soft’ rules either negotiated with crew unions and/or instigated company rules must be followed to arrive at a PTP solution.
For example, a short-haul domestic operation may allow crew to fly several sectors/legs per duty period, whereas a long-haul operation may only allow one sector/leg.  The legally-allowable duty period is determined by the time a flight duty starts and the number of sectors/legs flown.
Again, there are software programs to help develop a PTP solution automatically, but each airline is different and will have its own unique rule sets that will require separate programming.
The PTP solution will quantify the number of flying duties to be covered but now, it’s time to add the required level of standby coverage.  This is a very emotive subject.  How much risk is a company prepared to accept against 100% insurance that all eventualities of crew disruption are covered?  This might include sickness, emergency leave, strikes (anywhere within its route network) weather diversions and aircraft ‘tech’ delays, not to mention the odd volcano or two!
Once the number of duties has finally been established, divide (for our scenario) the 4.2 figure into the total weekly duties and you will arrive at the number of crew required.  For pilots the number will need to be multiplied by two giving the actual number of people required.
One slight complication here will be the addition of extra captains, some of whom will be training pilots whose contribution to the flying programme may only be 50% of a regular line pilot due to the senior pilots’ training commitments; this too must be taken into consideration.

Good crew rostering – ie, a sequence of flights planned without minimum rest periods, but including adequate standby coverage – will greatly help to keep a crew member’s roster stable. (Istock)

Roster Build and Publication

The area within crew scheduling that has benefited most from computerisation has been the crew roster build process.  This has dramatically reduced the number of staff required to produce crew rosters.  For example, I was part of a team of over 50 during the 1970s producing rosters for just long-haul cabin crew for a large international airline.  Then, when I moved to another similarly-sized airline that was using a computer system, only two people were building and producing rosters for both pilots and cabin crew.
Generally airlines have a choice and several options on how and what format to use when building rosters, and most companies will opt for a calendar month (roster period).  One example is the so-called ‘Fair Share’ method – assigning PTPs and days off to individual crew members each month – which, over several roster periods should ensure each crew will have a fair and equitable spread of days off and PTPs.
The second option may be ‘Limited Requests’, whereby crew members may request a small number of specific days off and PTPs for each roster period.  Another is the Bid Line.  Originally developed in North America, it enables crew members to bid for a ‘line of work’ each month and, depending upon their company seniority, will be assigned a line number for that period.  For example if a crew member is number 20 on the seniority list, he/she would have to bid for 20 individual lines of work as it is possible that their 19 more senior colleagues  could also bid for number 20’s choices.  There is also ‘Full Preferential Bidding’ where crew members can bid for days off and PTPs for a complete roster period.
A note here on crew seniority.  Airlines may opt for a seniority system that rewards loyalty to the company for roster bidding purposes.  A senior crew member will obviously have a better chance of being awarded his/her line of choice than a more junior crew member will.  However, some airlines have adopted a rotating seniority system so that all its crews will have the opportunity – over a period of several months – of obtaining their line of work, choice of days off and PTP preferences.
Irrespective of the rostering system that is used, the crew roster planners will start building a new roster by pre-assigning absent days, ie those for annual leave, long-term sickness, initial and recurrent training days and reserve lines.  In fact there is an almost endless stream of requests from the company’s in-flight cabin service and pilot fleet departments asking for crew members to be allocated time spent on a myriad of other duties other than the actual flying programme.
Only now can the ‘button’ be pressed for the actual roster build process to begin by using the preferred software program chosen by the airline.  For a large flying schedule this can take many hours or even several days, and still the first roster solution may not fully satisfy all of the company’s requirements – calling for another run of the roster build process after altering the computer program’s parameters.
The goal for roster perfection is to have a linear allocation of all days off, leave, training and flying duties.  To have peaks and troughs of any of these will result in crew shortages on certain days throughout a roster period.  Again computer software is being either used or developed to project training requirements, both recurrent and initial, to avoid peaks of training that might result in crew shortages.
Crews will often receive their newly-published rosters around seven days before they are active because the later a roster is produced, the more accurate it will be.  Obviously, the earlier a roster is published, the more likely it is to be disrupted by unforeseen circumstances like illnesses that will result in several changes and perhaps roster instability.
Airlines operate in a very dynamic environment and, as previously mentioned, have to contend with many uncontrollable factors that can disrupt the flying programme.  Good crew rostering – ie, a sequence of flights planned without minimum rest periods, but including adequate standby coverage – will greatly help to keep a crew member’s roster stable.
When received, the published rosters will inevitably be scrutinised by crew members keen to know why they didn’t receive a request for days off or a particular PTP – queries common in companies using the full preferential bidding system.  Managing crew expectations upon receiving their roster is essential.  The software that will provide airlines with the perfect roster solution has yet to be developed.