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Old February 21st 20, 10:38 AM posted to rec.aviation.soaring
John McCullagh[_2_]
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Posts: 7
Default Green band on ASI

This may seem a little academic, but definition of the lower limit of the
green band on ASIs is inconsistent in places.

EASA Certification Specifications for Sailplanes and Powered Sailplanes, CS
22.1545 (Air-speed indicator): "Each air-speed indicator must show the
following markings: ... (c) for the normal operating range, a green arc
with the lower limit at 1.1 VS1 with maximum weight and for wing-flaps
neutral (see AMC 22.335) and landing gear retracted and the upper limit at
the rough-air speed VRA."

So far so good. Many people fly aircraft certified to CS22, or its
predecessor JAR22. The latter dating back to at least 1981. Even before
that, the lower limit of the green band should have set according to the
flight manual.

However, the FAA Glider Flying Handbook seems to be at variance. It says
(p4-5):

* The lower limit of the green arc — stalling speed with the wing flaps
and landing gear retracted.

Since there is little reason to fly at less than min sink, flying at stall
speed doesn't seem like the normal operating range.