I've been participating in a discussion on airliners.net about a guy on a Singapore 777 wondering what the unusual vibrations are that he experienced on finals to Kuala Lumpur that could not be attributed to the spoilers, which were stowed. I suggested that it was caused by the flaps vibrating because they were at or near full flap setting and it was unusual to him because full flaps are not used on every landing.
As we know, the last notches of flaps usually create more drag than lift so buffeting of the flap can occur at those higher flap settings on planes from the 172 to the 777, caused by turbulent airflow on the back side of the flap.
Even in the 172 i wouldn't use full flaps unless i'm practicing short field landings or fast on the approach. So that explanation seemed to fly with them.
Some asian pilots in the forum stated that their operating procedures actually require a full flaps landing every time. Is this also the case in the US? I almost never experience vibrations when i'm riding in a jet unless they put out all the flaps. I'm also under the impression that US airlines prefer the pilots not use full flaps to save fuel and also to reduce environmental noise. Any input would be much appreciated.
john
As we know, the last notches of flaps usually create more drag than lift so buffeting of the flap can occur at those higher flap settings on planes from the 172 to the 777, caused by turbulent airflow on the back side of the flap.
Even in the 172 i wouldn't use full flaps unless i'm practicing short field landings or fast on the approach. So that explanation seemed to fly with them.
Some asian pilots in the forum stated that their operating procedures actually require a full flaps landing every time. Is this also the case in the US? I almost never experience vibrations when i'm riding in a jet unless they put out all the flaps. I'm also under the impression that US airlines prefer the pilots not use full flaps to save fuel and also to reduce environmental noise. Any input would be much appreciated.
john