Hélicoptères Guimbal
LETTRE SERVICE
CABRI G2
SL 12-001 A
Original issue
1 / 10
CABRI
®
G2
SERVICE LETTER 12-001
Yaw control in approach
It is recommended to keep this letter with the Flight Manual.
It is recommended to instructors that they insist on following matter during
training and that they check it periodically.
The Cabri G2 comprises a shrouded tail rotor, usually referred to as a
“Fenestron”
(*)
that was proven to provide excellent maneuverability in every
flight condition, in every direction of flight up to 40 kt at least.
However, two recent incidents involving a loss of control in yaw, both with pilots
with no previous flight experience in a Fenestron-equipped helicopter, lead
Hélicoptères Guimbal to issue this Service Letter in order to point out some
specific characteristics of such tail rotors. These characteristics are common to
all helicopters equipped with a Fenestron, and are covered by several
publications, including Eurocopter Service Letters N°1673-67-04 (CW rotors)
and 1692-67-04 (CCW rotors).
Important notes :
•
Spinning at the high rates that can be achieved in both directions by
applying and maintaining full pedal, can be very uncomfortable and disorienting
for the pilot, and thus very dangerous at low height. Avoid high rate of yaw
when close to the ground.
•
Extensive flight testing of the Cabri G2 and of other helicopters equipped
with a Fenestron have shown that such tail rotor, combining a large shroud and
a relatively high disk loading,
is immune to stall and to vortex-ring state
commonly referred to as LTE (Loss of Tail rotor Efficiency)
.
(*)
“Fenestron” is a registered trade mark of Eurocopter