| Home | Articles | CP reprints |
An Ohio VariViggen crashed just after making a tower flyby, to check an unsafe gear. Ground witness (pilot) reported an object fell off the engine then the engine sputtered and quit. The aircraft rolled sharply left, nose pitched up and the aircraft struck the ground in a high rate of sink. The pilot was fatally injured. Apparently the pilot tried to make a turn back to the runway but due to low altitude/airspeed the aircraft developed a high rate of sink and crashed before the turn could be completed.
A Michigan VariViggen crashed when the builder/pilot over-controlled in pitch just after his first take off in the aircraft. The aircraft was totally destroyed, but luckily the pilot survived with very minor injuries. The initial flights were flown by a qualified test pilot and he reported the aircraft was stable in all three axes and flew "practically hands off. Although the opportunity for a check out was available, the builder/pilot did not take advantage of it.
An Arizona VariEze crashed just after take off on its initial flight. The aircraft was destroyed and the builder/pilot received major injuries. We have requested, but not yet received, more details on this accident.
A Florida VariEze crashed when the canopy came open just after take off. The pilot was attempting a 180 degree turn back to the airport when the aircraft pitched down rolled left and contacted the ground. The aircraft was destroyed, the pilot received serious injuries.
A Missouri VariEze lost power just after take off and received major damage in the ensuing off field landing. The owner/pilot and his new bride were not injured. The engine failure was determined to be water in the fuel.
A Colorado VariEze crashed during landing approach when another aircraft pulled out in front of him for take off. The aircraft was totally destroyed, the pilot received very serious injuries. We have requested but not yet received details on the accident.
The Michigan VariViggen accident was apparently
precipitated by the pitch trim change with power change. An experienced pilot made the
first few flights on this Viggen and reported it to be hands off in all three axes, with
good flying qualities.
Without the invaluable benefit of a check out, the builder pilot made his first take off and was "surprised by the sudden rotation and immediately reduced power. Of course, due to the high thrust line, this caused the airplane to pitch up even more. He then slowly added power, but was probably slow enough to be sinking at this point, and the added power, pitched the nose down, only aggravating the situation. At this point the airplane was diving towards the ground, and as he put it, was as though at the bottom of a loop, and he smoothly applied back pressure to pull out, contacting the ground, wings level, but with enough force to virtually destroy the aircraft.
Fortunately, he was not seriously injured, but nevertheless, he has lost a very beautiful airplane, that he worked four years to build.
The pitch trim change with power on the Viggen is not extreme, nor abrupt, and is easily controlled. A low proficiency pilot can easily learn to compensate with the stick to maintain the proper attitude. However, on at least two instances we feel it has contributed to a serious accident with pilots who used abrupt power changes the very first time they were airborne and without the benefit of a checkout (see CP #12). What can we learn from this? Where possible, get at least a back seat check ride from an experienced Viggen pilot, with emphasis on the pitch trim change with abrupt power changes. Particularly at slow speed, and , above all avoid abrupt power changes at low speed until your proficiency allows.
Let me describe a normal take off in my Viggen N27MS. Set half to full reflex (depending on condition, first flight only half) line up on the runway, smoothly apply full throttle with the stick held all the way back. (full aft stick). The airplane will accelerate to 55 - 60 mph and then the canard will begin to fly. As I feel the nose slowly rotate, I smoothly bring the stick forward to pin the nose at the attitude I want for climb. A few seconds later the mains break ground and I get the gear on the way up and run the reflex down to cruise position.
Now, if I maintained the stick all the way back all that would happen, would be a rapid rotation with the steepest climb you could imagine provided the engine was running at full power, you would climb, but only at 300500 fpm (depending on gross wt and density altitude). This is not a smart thing to do, even though it can be done in the Viggen, because the abrupt loss of an engine would leave you in a tricky position. Immediate forward stick would probably save the day, but you would have to be sharp!
When we look at the Viggen program so far, obviously we have a problem. This appears to be pilot proficiency and preparedness. Read the owners manual and this article over and over. In all cases where pilots were experienced they had no trouble with the airplane at all. However in two cases now we have seen pilots lose their Viggens on the first lift off in a pitch change with power change. While this has never been a factor for us, it apparently still is a significant factor for a low time, low proficiency pilot. In order to emphasize this, re-read the complete write-up on test preparation, pilot preparation and test procedure in CP #12 Page 11. Also, if your Viggen is ready to fly, come to Mojave to take advantage of our offer to allow you to gain some proficiency in N27MS before you begin your testing.