Talk:Atlantic Airways Flight 670

Latest comment: 6 years ago by 95.149.173.52 in topic "Disemployment of the anti-lock braking system"

"Disemployment of the anti-lock braking system"

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Since 'disemployment' is meaningless in English, it is not clear what actually happened.188.230.248.85 (talk) 10:36, 12 May 2016 (UTC)Reply

The normal wheel brakes are fitted with anti-skid but the emergency brake is not, it is a simple no-frills brake for use in emergencies such as a mechanical failure of the main braking system. Instead of using the wheel brakes (which were working) normally and waiting for their effect to be felt, the pilot abandoned their use and instead applied the emergency brake and held it on, which lacking anti-skid, caused the aircraft tyres to then aquaplane on the water lying on the runway with a resulting lack of retardation in aircraft speed.
In an anti-skid system the aircraft wheels need time to rotate and run up-to-speed as the aircraft touches-down before the anti-skid mechanism will allow the brakes to be applied. On a wet runway the tyres may aquaplane momentarily or intermittently preventing the wheels from rotating and leading to the mistaken impression the brakes are not working. On a dry runway the wheels begin to rotate immediately on touchdown, and so the brakes are available at the same time.
In a skid the skidding-wheels are not rotating so an anti-skid system will not apply the brakes until they are rotating and they won't start rotating properly until they have firm, steady contact with solid ground, which on a wet runway may take several seconds before all the tyres penetrate the film of water lying on the runway surface.— Preceding unsigned comment added by 95.149.173.52 (talk) 09:42, 7 December 2017 (UTC)Reply