Brakes Were On Twice During Vietnam Airlines Delayed Takeoff

The preliminary report into the late takeoff of a Vietnam Airlines Boeing 787 at Munich in August says the brakes were applied twice from the left seat in the long takeoff run, including a nine-second period just before the pilots hauled the big Boeing off the grass overrun at 12 knots below rotate speed. They then pulled up so sharply the tail scraped and the plane’s automatic stall protection was activated and moved the slats to the gapped position, according to aviacionline.com. The excursion made a mess of approach lights and the airplane and after dumping 62 tonnes of fuel the plane made a safe landing, but all four tires on the left main gear blew or may have been damaged in the takeoff. All the focus is on the two recorded application of the brakes and the pedal movement that was recorded in both instances. However the complexity of the braking system makes gauging the influence of that pedal movement on the actual braking action difficult.

The aircraft’s data recorder logged a momentary application of brakes with corresponding pedal movement early in the takeoff run. Tire marks were left on the runway. About 48 seconds later, with the plane going 168 knots, the pedals moved and the brakes came on again for nine seconds leaving a long strip of rubber to the end of the runway. Although the brake pedals moved 60% of their potential travel distance (7.5°of a possible 12.5°) the actual braking action was only 27% on the left side and 17% on the right side. The aircraft’s anti-skid and other systems can actuate the brakes, too. The preliminary report reaches no conclusions or assessment of blame. The braking system components have been seized for further analysis.