Manufacturing is often all about the drumbeat. Takt time, how many units you must produce in an hour, a day or week to keep on schedule. Cars are measured in units per hour, jet aircraft per month.

At BAE Systems Military Air & Information in Warton, Lancashire, Matt Heritage is responsible for the biggest stage of final assembly of the Eurofighter Typhoon, the multi-partner €90 million aircraft that is Europe’s first “dual role” fighter jet, capable of operating in air-to-air or air-to-ground missions. Matt’s takt is one Typhoon every two weeks.

“I’m not building a Range Rover Evoque every 45-seconds,” says Heritage, Final Assembly Operations Manager. “But, in terms of drumbeat, I need to deliver an aircraft every two weeks and 24 is a lot in one year. We’ve never been at this rate before, we’ve got if for some years and if we get export orders we’ll have it for some time to come.”

“It’s all about hitting start rates. If you hit the starts, invariably you will hit output.”

Simplify a fighter jet production line and it sounds straightforward. The fuselage, which arrives in three pieces, is screwed together. You fit the engines, pipes, electronics and all the clever stuff, in order. Test for wiring faults and hydraulic leaks. Test the engine works. Run flight tests and deliver it.

The takt of 24 aircraft a year makes this far more challenging. Each key stage has a very defined “start”. “We need to be loading the brotje [laser line] every two weeks, paint an aircraft every two weeks and sell one every two weeks,” says Heritage.

“It’s all about hitting start rates. If you hit the starts, invariably you will hit output. If you get a problem that might stop the line, it’s about solving the problem rather than moving the starts.”

For aircraft makers, takt time is as important as for car manufacturers. As well as the team’s professional integrity and obligation to the customer, there are financial penalties, including liquidated damages, for missing trading dates. The team’s annual bonus is calculated partly on hitting milestone payments, which align with takts. Everyone here is watching the clock.

The Build Line

Fuselage sections, known as major units, arrive from one of the four partner countries – Germany, Italy, Spain and the UK. Team Zero – there are three teams – loads into a laser line brotje, a facility that uses lasers to marry up the three sections accurately. “We use this as much for repeatability as accuracy, to avoid a bottleneck,” says Heritage.

Wings are married here or in a separate area of the factory, depending on the brotje’s schedule. Once structural marry up is complete, the airframe is handed over to Team One, Matt’s team, for systems integration.

“Team One fit the pipes, the minor unit, foreplanes, the engines, missile eject launchers, the avionic trays, avionic boxes. We run a Dipma code test, running voltage through the aircraft to check there are no wiring faults, put hydraulic fluid into aircraft to check there are no leaks, check the ‘power-on’ system, ready for flight testing.” This stage takes about 12-weeks.

Teams within teams move around the aircraft, not vice versa. The team that fits avionic bay plugs and the Dipna code test, for example, will take two weeks, then move on to the next aircraft.

Team One hands over to Team Two, engine testing. Rolls-Royce, which makes the EJ200 engine as part of a consortium called Eurojet, is on-site full time. Flight testing, also at Warton, follows.

Scheduling master class

 Matt Heritage’s job is defined by pinpoint scheduling of skilled people – 72 in his team, 150 in the facility – to hit start rates at the correct build Matturity, borrowing and lending resources when stages are behind the master schedule, without compromising build quality.

“I have capacity to discharge 2,200 hours of labour a week. I am I getting 2,200 hours of achievement?” he recounts a typical daily thought. “Is it good achievement, or unscheduled growth i.e. ‘bad achievement’, which wasn’t in the plan?”

“So, I’ve scheduled 2,236 hours for Team One this week, more than normal, which means I have to hit all the planned load while next week hopefully I’ll have a lower load and I can deal with some unplanned work.”

To make this system work reliable, there is some buffer. For example, Team Two has a 12-week window in the plan, but they are configured to discharge in eight to 10 weeks providing they have a clean run of tests, when test equipment needs no calibration, etc. Team Two personnel with overcapacity could potentially help Team One with systems fitting.

Typhoon Assembly’s balancing act is that team managers have to be very parochial about their build stage, while having the altruism of working in a bigger team. “If Team Two can’t get a part to complete testing, I could take it off one of my aircraft, using my resource buffer to discharge some unplanned work for him, to keep him on programme. Dave [Team Two leader] is my customer.”

Within this variance of completion, ultiMattely build Matturity between Team One and Team Two has to be at a level where Team Two can test an aircraft. “I measure myself at a product Matturity benchmark of 95%, where I can hand over a very good aircraft to test,” says Heritage. “At the moment I’m delivering at 89%-95%. I want to be near 100% by year end.”