AIRCRAFT OPERATING INSTRUCTIONS – VIRUS 912 S-LSA GLIDER
Page
35
WARNING!
After having stopped spinning, recovering from the dive must be performed using gentle stick
movements (pull), rather than overstressing the aircraft. However, VNE must not be exceeded during this
maneuver.
When the aircraft is wings-level and flies horizontally, add throttle and resume normal flight.
Handling and maintenance of the GRS Rescue Parachute System.
Prior to every flight all visible parts of the system must be checked for proper condition. Special
attention should be paid to corrosion on the activation handle inside the cockpit. Also, main fastening
straps on the outside of the fuselage must be undamaged at all times. Furthermore, neither system, nor
any of its parts should be exposed to moisture, vibration and UV radiation for long periods of time to
ensure proper system operation and life.
CAUTION!
It is strongly recommenced to thoroughly inspect and grease the activation handle, preferably
using silicon spray, every 50 flight hours. All major repairs and damage repairs MUST be done by the
manufacturer or authorized service personnel.
For all details concerning the GRS rescue system, please see the “GRS - Galaxy Rescue System Manual for
Assembly and Use”.
How fast is too fast?
Based on two recent unfortunate events, where two pilots lost their newly acquired Sinus and Virus
aircraft, the team of Pipistrel’s factory pilots decided to stress the importance of airspeed even more. Do
read this passage thoroughly as everything mentioned below affects you as the pilot directly!
The two events
Both the events took place during the first couple of hours pilots flew with their new aircraft. Therefore
it is clear that they had not become completely familiar with all the flight capabilities offered by the Sinus
and Virus. The circumstances of both the events were remarkably similar. Soon after the pilots picked up
their new aircraft at the distributor’s facility, the aircraft were severely damaged aloft. One accident
occurred during the first home-bound cross country flight; and the other during the first flights at its
domestic airfield. Please note that the distributor had independently tested both mentioned aircraft up
to V
NE
at altitudes of 300 to 500 meters (900 to 1500 feet) without any problems. The new owner/pilots,
it was learned, flew their aircraft at higher altitudes, and very high speeds. One of them deployed
airbrakes (spoilers) at a speed of 285 km/h (155 kts) - where the V
NE
of the aircraft was only 225 km/h
(122 kts), the other was flying at 3000 m (10.000 ft) at 270 km/h (145 kts) IAS - where the VNE of the air-
craft was 250 km/h (135 kts).
They both encountered severe vibrations caused by flutter. As a result, one aircraft’s fuselage broke in
half just behind the cabin (the crew was saved thanks to the parachute rescue system), the other aircraft
suffered less serious damage, as only the flaperon control tubes were broken. The pilot of the second
machine then landed safely using elevator and rudder only. Fortunately both pilots survived the accident
without injury. Thanks to the Brauniger ALPHA Multifunction Display’s (MFD) integrated Flight Data
Recorder, we were able to reconstruct the flights and reveal what had really happened. What was the
reason for the flutter causing both accidents? Both pilots significantly exceeded VNE. With the IAS to
TAS correction factor taken into consideration, they were both flying faster than 315 km/h (170 kts)!
