In March the five-axis cell runs one shift and the setters repaint guards. In May a tranche of airframe fittings lands with a milestone date that cannot move. By June the same four setters are on twelve-hour days, the night shift is borrowing operators from deburring and the planner sleeps at the plant. In August two of the four resign.
Our guide to people issues in aero and defence supply names this swing as a standing hazard. It looks like a sales problem. Mostly it is a people-planning problem.
Symptoms of a tranche-driven floor
- Quiet months filled with housekeeping, repainting and 'find something to do', which skilled hands interpret as a sign that the unit is in trouble.
- Sudden overtime announced on a Friday for the following week, with no end date.
- Identical names on every extra shift: the setters, inspectors and solderers trusted with hard work.
- Weekly offs and compensatory leave postponed until 'after the delivery', then forgotten.
- Short-term hands hired for the peak, unable to touch the critical operations, so they add headcount without adding capacity where it matters.
What the swing costs
Exhaustion breeds costly slips. A tired setter mis-keys a work offset on titanium, a tired inspector misses a balloon on the dimensional report. Rework in the crunch eats the very hours the overtime bought.
Then comes attrition. The people who carried the last three crunches know they will carry the next. When a steadier offer arrives, they take it. Suppose the owner answered the last lull with lay-offs. Rebuilding for the next tranche then means hurried hiring. Good setters take months to find. There is a subtler loss too. Operators hired hastily for a peak often skip proper induction on records and stamping, so the following lull is spent untangling their travellers.
Why it keeps happening
Customer programmes move to their own clock. A prime contractor's release can slip by a quarter, then arrive all at once. Small suppliers rarely see the forecast, or see it and do not translate it into people. Overtime is the easiest lever on the day. And nobody tracks who absorbed the hours, so the load quietly concentrates on a handful of names. Planners count machine hours well but seldom count the hours of the few people who can set those machines.
What a good lull plan contains
A lull is the only time a busy aero-parts shop can invest in itself. Without a written plan, it fills with sweeping and anxiety. With one, the quiet weeks become the reason the next crunch is survivable.
- Cross-training targets by name: which operator learns which set-up, and who teaches.
- Machine work: spindle overhauls, probe recalibration, fixture refurbishment and coolant changes.
- Records: a traveller audit, stamp register clean-up and training file updates.
- Leave: owed weekly offs and compensatory days taken while they cost nothing in output.
- Improvement: one long-standing rework cause chosen and fixed by a small team.
Pin the lull plan beside the outlook board. When the floor sees named tasks rather than idle benches, rumours of closure lose their grip.
A step-by-step fix
- 1
Look back before you plan forward
Put last year's deliveries on one sheet and set overtime hours and missed weekly offs by person beside them. Circle the names that appear in every peak.
- 2
Build a rolling twelve-week skills outlook
Each month, list confirmed and likely tranches, the operations each needs and which named staff can run them. Gaps become visible weeks ahead.
- 3
Talk to the customer about release dates
Ask the buyer for their programme milestones and an early signal of slips. Even a rough view helps more than none.
- 4
Write a lull plan
Decide in advance what the quiet weeks are for: cross-training on critical operations, machine overhauls, fixture refurbishment, record audits and leave.
- 5
Set a fair overtime rota
Spread extra shifts across everyone qualified, limit back-to-back long days and post the rota early. Record who worked what.
- 6
Protect rest after a peak
Schedule postponed weekly offs and compensatory leave with dates, and keep the promise.
- 7
Tell the floor what is coming
Share the outlook at the monthly meeting. People cope with a crunch they saw coming far better than one that ambushes them.
Two checks before the next tranche
Check who is carrying the load now. If three names account for most overtime in the last two peaks, those three are your flight risk. Check whether quiet months have ever been used for cross-training. If not, the next lull is your first chance to widen the bench.
Staffing against an order book rather than the calendar is set out in defence parts workforce planning. For rosters in a machining cell, read rota rules for CNC aero-parts shops. The underlying method lives in our rota and leave design service.
