Hélicoptères Guimbal
SERVICE LETTER
CABRI G2
SL 11-001 A
Original issue
1 / 2
CABRI
®
G2
SERVICE LETTER 11-001
Safety and extreme maneuvers
It is recommended to keep this letter with the Flight Manual
Specific Cabri G2 rotor and dynamics design features give it the following
characteristics :
- A very large flight envelope,
- The capability to operate in high wind and gusts,
- A good ability to demonstrative autorotation and forgiving behavior,
- A high capability to recover from marginal flight condition,
- An extremely robust construction.
These characteristics may induce pilot’s excessive confidence.
HG therefore would like to highlight that once the Cabri G2 flight margins have
been overtaken (in terms of airspeed, rotor speed, maneuvers, performance or
weather conditions), the safety benefits that you can expect are cancelled.
HG insists on the fact that Flight Manual procedures should be followed for best
flight safety. Aerobatic flight, in particular, is forbidden.
HG would also like to point out that the Cabri G2 is equipped with a standard
reciprocating engine that is not designed for aerobatic, particularly low-G
flights : it looses all its power under those conditions.
But, unlike in an airplane, a helicopter engine may stall unexpectedly under
(forbidden) low-G operation and/or high nose-down pitch rate. This is due to the
freewheel which prevents the rotor from driving the engine.
HG demonstrated a good behavior of the engine in extreme maneuvers during
Cabri G2 development flight testing, but the engine manufacturer does not
guarantee its homogeneous behavior during such maneuvers, particularly
regarding its carburetor.
Above-quoted Cabri G2 flight characteristics make it one of the safest
helicopters to recover from an engine shutdown. In-flight engine restart has
been thoroughly demonstrated in the Cabri G2.
Pilot should however not deliberately provoke such risky situation.
If, despite all normal caution, any abnormal engine/carburetor behavior has
been or was to be encountered, it should be reported to HG to allow for further
improvement in safety.