Crossover speed B737NG

[ClearedILS25]

Hello!

first, Im new here, so hello everybody! It would be very kind if someone could answer me this question:
What is a crossover speed easy explained?Has it to do with the sideslip?

Thank you!


CI25

[Paul McKeksdown]

Search the internet with Yahoo etc...

Type in crossover speed...

and you'll get the full explaination. However a single line that I found (I didn't know what it was either:D ):

The speed at which full lateral (roll) control is needed to balance the roll due to sideslip caused by full rudder deflection is referred to the "Crossover" speed

[Alex Whittingham]

The JAA use a term 'crossover altitude' in the ATPL exams to describe the point where the speed schedule changes in a climb or descent between IAS and Mach number.

An aircraft might, for instance, be planned to climb at 300kt indicated until the Mach number increases to M0.8 and thereafter hold M0.8 with a decreasing IAS. This would be normally described as a climb schedule of 300KIAS/M0.8 and the crossover altitude would be about 30,000ft.

In the descent it might be scheduled to go down at M0.78 until the IAS hits 320kts, a schedule of M0.78/320KIAS. If we called the 320kts here the 'crossover speed' would that fit the context?

[Alex Whittingham]

Looks like that was a red herring I introduced there. A google search (as recommended above) produces lots of stuff on this term, which was new to me, that has come to prominence after the USAIR B737 experienced the rudder 'hard over' and crashed near Pittsburgh in 1994.

link (http://www.avweb.com/other/us427vue.html)