Behind every safe landing at Changi Airport, is a Saab 9-5 that's unlike any other car

In the dead of night, an array of about 20 vehicles and about 60 experienced staff descend onto the long dark patch of tarmac that makes up one of three runways that service the busy Changi Airport. Their job - inspect, repair, and clean the entire 4.0 km stretch within about 4 hours before the runway is reopened.

According to The Straits Times who were granted special access, at times, waiting planes are mere minutes behind the team, jostling to take off on the busy runway.

The vehicles range from lorries to specialised cleaning trucks and perhaps the most remarkable, the Runway Friction Testers (RFT). A salvo of Saab 9-5 SportCombis that have been specially modified to hold a massive 550-litre water tank mounted where the rear seats used to be, as well as a specialised wheel that extends from the rear undercarriage.

The job of the Saab 9-5 friction testers is to race up to a designated speed quickly, before spraying a thin film of water on the tarmac, and dragging the wheel to measure the friction levels on the runway. The friction testers have to perform four runs across specific portions of the runway, with each test taking about 15 minutes.

The friction testers perform an important task that helps ensure planes land safely. Crucially, this testing allows airports to evaluate surface friction including changes due to weather and rubber contamination.

The Saab 9-5 SportCombi you see here is a battle-hardened workhorse; its odometer reads 175,157 km, most of which involved quick acceleration bursts to 95 km/h – 97 km/h, whilst carrying a few hundred kgs of water and specialised equipment down a runway.

There are hardly any visual markers besides on the runway at night, outfitted with spotlights, the tests rely on the 9-5 SportCombis tracking straight and true down the entire runway. At the end, drivers have just 300 meters (in sheer darkness) to bring the car to a safe stop, before the test is repeated.

Fun fact: before Changi Airport started using 9-5 SportCombis, the airport used modified Lamborghini Countach supercars as friction testers.

The tests prove the sheer engineering, power and reliability of the 9-5 SportCombis, and even pay homage to Saab’s roots in the aviation industry. Preceding the 9-5 SportCombis, the Saab 900 Turbo was also commonly used in airports around the world.

The Saab 9-5 SportCombi you see here will soon be retired and replaced with a new VW Transporter van soon, but it has served as a testament to the brilliant engineering of the somewhat quirky, and now defunct, Saab car company.