The aircraft was operating as Flight QF004/145 from San Francisco to Sydney, cruising at flight level 390 in smooth, clear, moonless conditions. The aircraft Captain occupied the left control position and the Second Officer occupied the right. The weather radar system was serviceable and operating. No significant weather had been forecast or observed by the crew during the flight. Although the "fasten seatbelt" signs had earlier been turned off, passengers had been advised, by cabin announcements, that it was recommended that seat belts should be worn unless moving around the cabin. This information was also included in the passenger safety briefing cards as well as being stamped onto each seatbelt buckle. About six hours after leaving San Francisco, the Captain noticed stars he had observed from his left window were becoming obscured. Upon closer inspection he noticed cloud ahead, and to the left of, the aircraft. Although no weather radar returns were apparent, the Captain took the precaution of turning on the fasten seatbelt signs. Approximately 15 seconds later the aircraft encountered a short period of moderate to severe turbulence. A number of passengers and flight attendants were flung about the cabin, incurring minor injuries as they struck fixed objects. Damage to the aircraft was minor and confined to internal fittings. After considering the condition of the injured, the enroute medical facilities and the superficial nature of the aircraft damage, the Captain decided the flight should continue as planned. The aircraft subsequently landed at Sydney where further medical treatment was provided. Twenty passengers required short term treatment in hospital. The investigation of the incident revealed that the flight crew had operated the aircraft in accordance with approved company procedures. Their knowledge, and use, of the weather radar systems was considered satisfactory. All weather radar systems depend on the fact that water particles, either in suspension (cloud) or as rainfall, will reflect a radar energy beam to an extent generally dependent upon the density and size of the water droplets. The aircraft encountered vertical air currents associated with an isolated towering cumulus cloud, which evidently contained insufficient moisture to be detectable by weather radar.

The pilot was approaching to land at the end of a local soaring flight. He commenced final approach at a satisfactory height and speed. The air brakes were selected half extended in order to control the approach. A short time later the aircraft began to slow down and sink more rapidly than the pilot desired so he lowered the nose and attempted to retract the air brakes. He was unable to retract the brakes and the aircraft struck the boundary fence short of the runway. On later consideration of his actions the pilot found that he had been trying to extend the airbrakes rather than retract them. He considered that this was due his anxiety at the high rate of descent that had developed. The initial high rate of descent was probably a result of unexpected sink encountered on approach.

When the pilot departed the aerodrome the wind strength was reported to be 18 knots. However, by the time the pilot returned for a landing the wind strength had increased significantly with gusts reported to have reached 30 knots. The pilot landed the aircraft successfully, but as he started to taxi a wind gust caused the right wing to rise. The left wingtip then contacted the ground and the aircraft nosed down resulting in the propeller also striking the ground. The aircraft then pirouetted around the wingtip and somersaulted onto its back. The strong wind sprang up during the time the pilot was flying in the local training area. After landing the pilot was unable to attract the attention of persons who could have acted as wing walkers and despite having placed the control column in the full back and full right position, he was unable to prevent the right wing from rising. This accident was not the subject of a formal on-site investigation.

Prior to landing the gear was selected down and a normal gear down indication obtained. The touch down was normal but when the airspeed was reduced to about 65 knots a vibration similar to a wheel shimmy developed. Attempts were made to keep the aircraft straight with brake and rudder but when it was realised that the right maingear was not supporting the aircraft the right engine was shut down. Investigation revealed that the uplock bracket spring had become detached from the uplock bracket. This along with some corrosion and stiffness in the bracket pivot bolt caused the bracket and uplock not to be withdrawn during the extension sequence. As a result the extension rod was bent during the extension cycle and the right gear did not extend. There is no provision made for lubrication of the bracket pivot bolt and no requirement for regular removal and servicing of this item. The pilot was unaware of the gear malfunction due to the design feature of the system which does not indicate gear-leg position but only the extent of gear-box travel.

Due to wind conditions at the landing site, the pilot decided that a firm touchdown was required to avoid the possibility of the balloon dragging. The landing was not heavy, but as the balloon touched down a passenger released her grip of the hand hold. As the basket leaned, she fell forward and struck the fuel cylinder, breaking two ribs.

Circumstances:

The pilot has reported that on the final leg of a competition cross country flight he was forced to make an outlanding. He reported that he flew a full circuit for the selected landing site and completed his checks on the downwind leg. Shortly before touchdown, the glider encountered some turbulence, and the landing gear warning horn sounded. The pilot suspected that the landing gear was not fully locked down. To check the landing gear, he released the speed brake control from his left hand and transferred that hand to the control column. This allowed him to check the landing gear lever with his right hand. During this transfer of hands, he lost control of the glider which impacted the ground and suffered substantial damage. The landing gear was found to be "in-transit" after the glider came to rest. Subsequent investigation by the gliding club showed that the landing gear lever could be moved in its detent such that the warning horn micro-switch operated while the landing gear was still down and locked. It is possible that when the horn operated during turbulence on the approach the pilot moved the gear lever forward which acted to retract the landing gear. The pilot was relatively inexperienced and suggested that when the warning horn sounded, he was startled and moved the landing gear lever in the direction he became used to while recently training in the IS-28 glider. This was opposite to the movement required in the Hornet.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. While at low altitude during an outlanding the pilot was startled when the landing gear warning horn sounded.

2. The landing gear mechanism was not correctly adjusted.

3. The pilot changed hands on the control column so he could move the landing gear lever. During this action he lost control of the glider. This accident was not the subject of an on-scene investigation.

The student was carrying out a crosswind landing under the supervision of the instructor who occupied the rear tandem seat. A witness reported that the speed of the aircraft on approach was higher than normal. The airbrakes were closed prior to the flare and the aircraft subsequently ballooned to a height of about 50 feet above the ground. The aircraft appeared to remain under control but it landed heavily and bounced back into the air. On the following touchdown one wing contacted the ground and the glider groundlooped.

The pilot had landed at the strip on a number of previous occasions, but this was the first time in this aircraft type. To give himself more time the pilot made a longer than normal final approach. At about 100 feet above the ground, with the airspeed at about 65 knots, the aircraft began to sink. The pilot applied full power to commence a go-around and as the nose pitched up, the left wing dropped. The pilot did not prevent the nose of the aircraft pitching up, thus aggravating the almost stalled condition of the aircraft. Power was then reduced and the aircraft landed heavily in a wheat paddock along side the strip and slid sideways as it came to rest.

The pilot reported that as he applied full power for takeoff, on strip 32, the aircraft began to swing to the left. He was unable to correct the situation and the aircraft ran off the strip and collided with trees. The wind velocity at the time was reported by the pilot to have been a light south-westerly. The topography surrounding the strip is known to give rise to sudden and unpredictable wind gusts and it is possible that the aircraft encountered such a gust as the takeoff run was commenced.

The pilot was conducting a flight to satisfy distance, height and duration requirements for the silver endorsement on his gliding certificate. One of the requirements was that the flight should last for at least five hours. After about three hours flying the pilot felt slightly nauseous, and about an hour later he became extremely nauseous and vomitted. His condition then improved, and he elected to continue the flight. He subsequently arrived in the circuit area at an indicated altitude of 2500 feet, and intended over- flying the field before joining a left circuit to land. He was aware that the angle was unusual but deferred to his altimeter, assuming his perception had changed as he had been above 5000 feet for most of the flight. He then realised that the aircraft was much lower than the indicated height and that a landing on the intended strip would not be possible. While manoeuvring to land on another strip, the left wing tip touched the ground and the aircraft swung through about 120 degrees before striking the ground heavily. After the accident the pilot discovered that he had inadvertently set 1000 feet instead of zero on his altimeter before DEPARTURE. The pilot was aware of the problems of sun exposure and had taken suitable precautions. These precautions were apparently insufficient to counter the effects of dehydration and heat stress.