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MODIFICATION OF GADRINGER FB19 HARNESS BUCKLE, TONGUE HALF, TO PREVENT FAILURE TO RELEASE UNDER EMERGENCY CONDITIONS 

Applicable to all gliders, Powered Sailplanes and Power Assisted Sailplanes fitted with pilot harness systems incorporating GADRINGER FB19 BUCKLE ASSEMBLIES. NO OTHER PILOT HARNESSES ARE AFFECTED. Early in 1989 an Australian pilot experienced difficulty while trying to bail out immediately after a mid-air collision. His delayed exit was caused by the two lap strap buckle halves jamming and locking together. Investigation of this incident has established a large amount of background information. Over recent years, many pilot harness assemblies have been subject to renewal of harness straps, replacement of abdominal pads and other repairs and miscellaneous modifications, dictated by age, condition and the high cost of new harness assemblies. Repair and refurbish work has been completed by a wide range of organizations and individuals not all of whom have followed G.F.A. harness repair guidelines, or requested G.F.A. design approval for non standard repairs and modifications. The original Gadringer harness system,fitted with the FB 19 Buckle was fitted with two, large, abdominal support pads. These two pads not only provided good abdominal support THEY ALSO PREVENTED THE TWO BUCKLE HALVES ENGAGING TOO FAR, THEREBY PREVENTING THE TWO HALVES JAMMING TOGETHER. The fit of the buckle halves with the correct, original pads is shown in figures 2 and 3. The pad overlap and their stiffness ensuring correct buckle alignment. Some refurbished harnesses have no abdominal pads at all. Some have small pads as shown in Figure 4 which do not support or align the buckle halves correctly.Some original Gadringer harness assemblies may be in service with no abdominal pads, the original pads being removed because of deteriorated condition. Some ORIGINAL Gadringer harnesses still in service may have ORIGINAL abdominal pads which are in such poor condition they may no longer prevent jamming of the two buckle halves. The harness involved in the above incident displayed a considerable change in the bendup angle of the buckle tongue. This may have been damage incurred during the accident or may have been man made at sometime in the past. ANY CHANGE IN THIS ANGLE WILL AFFECT THE EASE OF DISENGAGEMENT OF THE TWO BUCKLE HALVES.