ones we use frequently to increase our margins
against unplanned encounters with terra firma.
The reason, perhaps, is that these speeds change
with the flight conditions. As density altitude and
aircraft weight change, so do Vx and Vy. Another
speed that changes with weight is maneuvering
speed, or VA. And like VNE, it’s one we should keep
our eyes on, particularly if we enjoy the company
of our wings.
The textbook definition of VA is “the highest
speed at which full, abrupt control maneuvers
may be employed without exceeding the struc-
tural limits of the aircraft.” In other words, at any
The problem is that the
maneuvering speed published
in the pilot’s operating hand-
book is that of the aircraft at
maximum gross weight.
speed below VA, the aircraft should stall before it
breaks. That would seem to imply that as long as
we keep it below VA, we’re free to yank and bank
as we please without concern over the structural
integrity of our aircraft. Sound about right?
Not quite. As it turns out, even at maneuvering
speed, we can experience structural damage, or
even failure, of our aircraft’s most precious
appendages. For this reason, a more detailed look
at maneuvering speed—what it is, what it really
means, and how it changes—is worth a few minutes of our time.
A COMMON MISCONCEPTION
To many pilots, it seems only natural that as the
weight of the aircraft decreases, it should be possible to go faster. In truth, VA actually decreases as
weight decreases—much the same as Vx and Vy
decrease as weight decreases. One way to wrap
our heads around the concept is to think of a
truck rapidly crossing the railroad tracks. If the
truck is heavily loaded, it will hardly bounce as it
crosses the tracks. If that same truck is lightly
loaded as it crosses the tracks at the same speed,
it will bounce madly. The input—the displacement of the tires caused by hitting the tracks—is
the same whether the truck is loaded or empty.
