Appendix
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 aects you as the pilot directly!
The two events
Both the events took place during the rst couple of hours pilots ew with their new aircrafts.
Therefore it is denite they had not become completely familiar with all the ight stages Sinus and
Virus oer. The circumstances of both the events were remarkably simmilar.
Soon after the pilots picked up their new aircraft at the distributor’s, the aircraft were severely dam-
aged aloft. One during the rst home-bound cross country ight and the other during the rst
ights at domestic aireld. Please note the distrubutor independently tested both mentioned air-
craft up to VNE at altitudes reaching 300 to 500 metres (900 to 1500 feet) with great success.
Pilots ew their machines at reasonably high altitudes but at very high speeds. One of them de-
ployed airbrakes (spoilers) at the speed of 285 km/h (155 kts), the other was ying at 3000 m
(10.000 ft) at 270 km/h (145 kts) IAS.
They both encountered severe vibrations caused by utter. Because of this one aircraft’s fuselage
was shreaded and broken in half just behind the cabin (the craw saw saved thanks to the parachute
rescue system), other suered inferior damage as only the apperon control tubes went broken. The
pilot of the second machine then landed safely using elevator and rudder only. Fortunately both pi-
lots survived the accident without being even slightely injured.
Thanks to the Brauniger ALPHAmfd’s integrated Flight Data Recorder, we were able to reconstruct
the ights and reveal what had really happened.
What was the reason for the utter causing both accidents?
Both pilots greatly exceeded speed which should never be exceeded, the VNE.
With the IAS to TAS correction factor taken into consideration, they were both ying
faster than 315 km/h (170 kts)!
You might say: “Why did they not keep their speed within safe limits? How could they be so thought-
less to aord themselves exceeding the VNE?” Speaking with the two pilots they both confessed
they went over the line unawarely. “All just happened so suddenly!” was what they both said.
Therefore it is of vital importance to be familiar to all factors that might inuence your ying to the
point of unawarely exceeding the VNE.
Human factor and performance
The human body is not intended to be travelling at 250 km/h (135 kts), nor is it built to y. Therefore,
in ight, the human body and its signals should not be trusted at all times!
To determine the speed you are travelling at, you usually rely on two senses – the ear and the eye.
The faster the objects around are passing by, the faster you are travelling. True.
The stronger the noise caused by air circulating the airframe, the faster the airspeed. True again.
But let us conne ourselves to both events’ scenarios.
At higher altitudes, human eye loses it’s ability to determine the speed of movement precisely.
Because of that pilots, who are ying high up feel like they are ying terribly slow.
To Next Page
Loading...
Need help?
General
