Bio15 From Colombia, joined Mar 2001, 1089 posts, RR: 7 Posted (12 years 9 months 23 hours ago) and read 5084 times:
Hi everyone. I would just like to know if there is a different stick used to activate the ground spoilers, or if the same speed brake handle is used. If they are the same, what determines when to deploy ground spoilers and when the speed brakes (or both at a time)?
I have known that quick descents are not uncommon, and that high descent rates can be achieved by the aircraft. I wanted to know if there are any limitations due to pressurization issues as to the descent speed. I once went into a 767 flight deck and noticed the VS pointing to the -4500 fpm, which I thought was rather high. Is it really?
Seiple From , joined Dec 1969, posts, RR:
Reply 1, posted (12 years 9 months 23 hours ago) and read 5069 times:
In flight, the flight spoilers are activated by the speed brake handle. I know that Boeings have a spoiler mixer that activates them in proportion to the ailerons for better roll control.
Ground spoilers will only activate on the ground. They require weight on wheels via a squat switch or something similar. When arming the spoilers, normally one set (flight or ground) will deploy with the squat switch activation while the other set requires some sort of power input (such as reverse thrust).
The ground spoilers are normally actuated using the spoiler handle. The handle is most normally located to the immediate left of the throttle levers. They may also be deployed on landing automatically through an electrical actuator connected to the control quadrant under the floor. On many aircraft there is an interlock so that the ground spoilers do not operate in flight or when the aircraft weight is not on the landing gear. The flight spoilers normally work through a mixing or proportioning mechanism to compliment the ailerons thus requiring less aileron deflection to achieve a higher roll rate. They deploy with the ground spoilers when the spoiler handle is pulled.
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
AAR90 From United States of America, joined Jan 2000, 3526 posts, RR: 44
Reply 3, posted (12 years 9 months 19 hours ago) and read 4998 times:
Depends upon the aircraft. Most utilize a single "speedbrake" or "spoiler" handle. Some of those have a "flight" limit position and some do not. Those that do "normally" utilize some form of physical restriction to prohibit movement beyond the flight limit when no weight on wheels is sensed. Notice the use of "some" and "normally." Naturally there are exceptions. i.e. F-100 uses "Lift Dumpers" which are "armed" by the pilots and activate with weight on wheels sensing.
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