Accidents and Incidents
October 1986
A Kansas based VariEze crashed, fatally injuring it's builder/pilot. The circumstances of this crash are the stuff nightmares are made of. The left wing separated from the fuselage in flight and the airplane fell out of control to the ground where the right wing also separated from the fuselage. Examination of the wreckage showed that the 16 screws (AN-509/AN-525) that must be used to fasten the wing-attach fittings to each wing spar were never installed! Suprisingly, the same 16 screws that are used to attach the wing-attach fittings to the centersection spar were installed. As a result only the epoxy bond held the wings to their fittings. Incredibly, this enabled the aircraft to fly for a number of hours before the top and bottom spar caps simply pulled out of the metal wing attach fitting.
This builder/pilot, by all reports, was a careful builder who built his VariEze closely to the plans, yet while he did install the wing attach screws into each end of the centersection spar, he somehow overlooked the installation of these critical screws into each wing. Why? We will probably never know, but we should all Iearn a lesson from this. Even though the plans are clear and concise, with full size drawings showing the location of these screws, it is apparently possible to overlook such a vitally important structural attachment. Every VariEze builder or flyer should check to be absolutely certain that all 64 screws are installed in the wing/centersection attach fittings.
If you have already covered these screws, such as in an already completed and finished airplane, you can easily check using a small magnet hanging on a string, or a stud finder such as carpenters use to locate vertical studs in a wall (it's also a magnet). Carefully mark the exact location of each screw head with a pencil. Compare your bolt pattern with the full scale drawing In the plans. Be sure that you have all 64 screws in the correct positions. This applies especially to those who have not done this work themselves and therefore would not know.
A Texas Long-EZ lost power and hit power lines as the pilot attempted an emergency landing. The airplane nosed over and crashed, seriously injuring the pilot. The reason for the power failure has not been positively determined. A California VariEze lost power while on a cross country flight still 200 miles from the pilot's intended destination. The pilot landed on a highway, crashing through a fence. The VariEze was heavily damaged but the pilot walked away with cuts and bruises. The reason for the power failure has not been positively determined. What can be learned from this type of accident? Complete engine failure, if not a mechanical failure such as a broken crankshaft or connecting rod(s), is generally fuel associated . With redundant magnetos, ingition is sel ofn cause for a complete and sudden engine stoppage.
Catastrophic mechanical failures, while they do occur from time to time, are quite rare in aircraft engines. Sticky or stuck valves occur more often, but again, this seldom causes a complete power failure. Most of these types of failures will result in a partial loss of power which, while very nerve wracking, should still enable a pilot who stays cool to reach an airport or, at least, make a safe emergency landing. Fuel related engine problems in homebuilts generally come under two headings: simply running out of fuel (brain failure!), or a faulty fuel system that for one reason or another fails to allow fuel to reach the engine. This could be caused by many things. Deviating from the plans is probably the most common reason. Clogged filters, substandard hoses or fittings, old, worn-out carburetors, sticking floats, wrong fuel pumps, disregarded inspections, - we could go on all day! RAF is not an engine oriented company, our expertise is in aerodynamics and composite structures.
While we have some experience with engines, we can only offer general guide lines. Get expert help with your engine installation. Check with the local airport mechanics, have other members of your EAA chapter look at your engine controls/hookups, your baffling, your fuel lines, etc. Tony Bengelis' book Firewall Forward is a great source of information on engine installations. Before first flight, do conduct a fuel flow evaluation per owners manual Appendix 1. For a Long-EZ, this test should also be conducted with the electric boost pump running. The flow should now be at least 20 gph. If these flows are not achieved, do not attempt to fly until you have located and corrected the problem. if your engine cannot get fuel, it will cease to run. This will give you an immediate, very serious problem which, unless you happen to be over or near a suitable landing site and unless you keep cool and judge it perfectly, could possibly result in the loss of your life.