Aircrafts have to undergo periodic Maintenance, Repair and Overhaul (MRO). This is mandatory in order to insure the aircraft’s airworthiness and overall safety. During these inspections and repairs, the aircrafts are grounded.
For the owners and operators, the shorter the turnaround time*, the better. An aircraft is a huge investment and the ROI is only when it can be used in service.
*the time the aircraft is grounded, usually counted in weeks for longer in-depth inspections.
Yet aircraft operational availability is not only a question of Return On Investment, think about relief and the lives saved by medivacs or military forces brought closer to their spot during a crisis.
When an aircraft comes in for its scheduled maintenance, according to the type of inspection (ranging from Check A to Check D, according the depth and importance of inspection, the amount of time or usage… (see Wikipedia)
The process is scheduled like a project as many tasks can’t be done prior to some others, e.g. access some hydraulic pipes before stripping the surrounding frame.
It is therefore common to use Project Management tools and techniques to organize, carry-out and monitor the whole process.
Shortening the turnaround time is therefore a challenge for the service centers, not only to please and retain their customers, but also to attract new ones in order to grow their business and improve their profitability.
Of course the challenge is to be met while remaining compliant to the severe regulations and specific constraints, taking no chances with quality nor safety.
Furthermore, “findings” – unexpected defects of potential issues found once the aircraft is under inspection – or sudden customers requirements may add unscheduled workload.
In the traditional project management way, each task is estimated for its duration and a cautious (and generous) margin of time added. The service centers want to keep their committed due date, even if findings or any other random events (parts shortages, supplies problems…) arise.
It is therefore no surprise that major Checks ground an aircraft for weeks.
The new approach
It wasn’t long before some service centers spotted the improvement potential (turnaround time reduction) with Critical Chain Project Management (CCPM). Delta TechOps, Lufthansa Technik, US Navy and Air Force, French SiAé are cases I’m aware of.
Compared to traditional Critical Path Method (CPM), Critical Chain Project Management takes the resources’ limited capacities into account at once and has a completely different approach regarding margin of time. In short, all margins are shortened based on a statistical rationale and a share of it put into a global protective time buffer.
CCPM provides also a simple but very effective visual indicator to monitor both project’s achievement and protective buffer consumption, thus indicating instantly when the project may be late. This robust and early warning allows project managers to focus on a very limited number of issues instead of trying to control every single task.
This allows also the mechanics to work in a quieter atmosphere, an important additional benefit in a trade that considers human stress as a major risk for quality.
CCPM has proven great for consistently meeting due dates and often shortening a whole project duration compared to its original estimations.
Our client testimony
I was fortunate to be involved in Embraer’s Business Jets Service Center’s project to reduce turnaround time in Paris (Le-Bourget) and pleased to produce a series of videos of their testimonies about their achievement.
In this video, Sébastien Albouy, Director of Embraer Executive Jets Services center in Paris Le Bourget executive airport, explains how Critical Chain Project Management helped to drastically shorten the aircraft turnaround time, thus increasing aircraft availability and the center’s capacity.
>Related: TOC, Lean and aviation MRO