It’s not necessarily obvious, yet all commercial aircraft today are equipped with the same system. After takeoff, their front landing-gear retracts in a forward direction, from the rear, towards the front of the plane, and when landing, lowered in the reverse direction. But why? To find out, we went to see a specialist who works for the supplier OEM Safran Landing Systems (former Messier-Bugatti-Dowty) near Paris. His explanation is simple, it's actually for security issues when the landing gear is being lowered in case of a hydraulic system failure.
Pierre Woerner, Expert Landing Gears - Safran Landing Systems: interview in the video.
The landing gear control circuit is in fact linked to the hydraulic circuit of the aircraft. In the event of hydraulic failure, this system allows landing gear to lower itself, ‘‘manually’’ so to speak. If some ‘planes from the 40’s era, such as the Lockheed Constellation, are perfect examples which operated in the opposite fashion, with its forward landing gear lowering from the rear to the front, it was because they were equipped with not one, but two hydraulic circuits.
As for the main landing gear, they are retracted and lowered laterally since their weight gives them a big advantage compared to that of the nose landing gear.
Pierre Woerner, Expert Landing Gears - Safran Landing Systems: interview in the video.
Regarding the retraction and lowering system of the nose landing gear, it is now imposed by the EU and US civil aviation authorities. No wonder, therefore, that all airliners are equipped with the same type of system.
