Loss of control

The pilot was departing into strong and gusty wind conditions. The aircraft was observed to climb steeply to about 200 feet above ground level. It then entered a descending turn to the right, at a low airspeed. The descent continued with the aircraft in a nose high attitude, and a wing was seen to drop shortly before ground impact. The pilot subsequently reported the engine was delivering full power throughout the flight. Another pilot who had flown a number of flights in the area during the day, reported that he had encountered pronounced areas of sink to the north of the strip. It was considered that while attempting to fly out of similar conditions, the pilot had allowed the airspeed to decay and the aircraft had stalled. There had been insufficient height available for the pilot to effect recovery. This accident was not the subject of an on-scene investigation.

Circumstances:

The pilot was undergoing a check flight with an instructor, as he was contemplating purchasing this type of aircraft. This was the first occasion that the pilot and instructor had flown together. A series of exercises was carried out, during which the pilot was asked to demonstrate a power on stall at a height of approximately 500 feet. During this exercise, the pilot did not lower the nose sufficiently during the recovery. The pilot was not accustomed to practising stalling at such a low altitude, and during his previous training this had been carried out at 1500 feet. After some discussion another stall recovery was carried out, and on this occasion the pilot used the correct technique. The instructor then decided to return to the strip to carry out some circuits and landings as he assessed the pilot to be unsuitable to fly solo. The flying technique required by the instructor was generally at variance to that previously experienced by the pilot, and it would appear that the check flight was rather vigorous without the opportunity to become accustomed to the environment. During the return flight, the instructor described the circumstances which could cause the aircraft to stall during a forced landing with no power. To demonstrate this, he then closed the throttle at a height of between 300 and 500 feet, and asked the pilot to adopt a glide attitude, initiate a stall and then effect a recovery without the use of engine power. The pilot did not lower the nose sufficiently after the stall symptoms appeared, and he was told to further lower the nose, as a steep nose down attitude is required to effect this type of recovery. When the pilot did not commence to ease the aircraft out of the ensuing dive, the instructor called that he was taking over, but he was unable to move the controls. The pilot had become rigid at the controls, the instructor was unable to correct the situation, and the aircraft remained in a pronounced nose down attitude until ground impact.

Significant Factors:

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

1. The instructor was carrying out stalling practice at a low height.

2. The pilot mishandled the controls, probably due to misapprehension.

3. The pilot apparently panicked and became rigid on the controls when the aircraft was in a steep nose down attitude near the ground.

4. The instructor was unable to regain control of the aircraft before it struck the ground.

Recommendations:

The Civil Aviation Authority in conjunction with the Australian Ultralight Federation, should consider specifying minimum heights above ground level for ultralight aircraft engaged in stalling, spinning and unusual attitude recovery practice.

After takeoff, the aircraft was observed to accelerate at a low height above the strip. At the upwind end, the pilot initiated a steep climb and a steep turn to the right, however the aircraft stalled at about 150 feet above the ground. The aircraft struck the ground heavily and slid into a ringlock fence. The pilot freed himself from the wreckage, and the engine which was still running at high speed, was shut down by a spectator. The pilot reported that after the ultralight stalled, he had the stick full back, but the aircraft would not recover. The aircraft stalled as a result of the steep climbing turn but recovery was not effected due to incorrect stall recovery technique.

Analysis of a video recording taken of the take-off run by the occupant of the front seat, indicated that the aircraft became airborne after a ground roll of about 18 seconds. The aircraft then continued in the direction of takeoff for a further 11 seconds at what appeared to be near to takeoff speed. The aircraft did not climb away. It was not clear from the recording whether or not the aircraft was airborne throughout the 11 seconds. At the end of this time however, the aircraft was on the ground and it then veered sharply to the right. At the time the prevailing wind was a left quartering crosswind. The pilot was unable to regain directional control and the aircraft ran off the side of the strip and struck an embankment before coming to rest inverted. No defect was found with the engine or flight controls and the aircraft weight and centre of gravity were within the required limits. The aircraft had been fitted with a braking system and had recorded 27 hours in service since the modification. An examination of the brake shoes revealed an excessive rate of wear to the left brake shoes, and a cable within the braking system was found to be incorrectly adjusted. However, whether these defects contributed to the development of the accident could not be established. The reason for the loss of directional control was not determined.

During the takeoff run, the pilot reported that the aircraft encountered a crosswind from the left. Despite the application of left rudder and aileron the aircraft continued to drift towards the right of the strip. The pilot attempted to manoeuvre the aircraft over a gable marker but one of the mainwheels struck the marker and caused the aircraft to turn further to the right. The aircraft continued and the lower right wing was torn off after it struck a fence post. The aircraft came to rest 13 metres beyond the boundary fence. During the takeoff the wind velocity had changed appreciably and the aircraft had drifted well to the right of the strip before the pilot had attempted to take corrective action. The takeoff was not abandoned until after the aircraft had struck the fence.

The pilot was conducting a navigational exercise from Benalla to Benalla via overhead Tocumwal N.S.W. The wind conditions were northerly and gusting. The pilot realised he would be unable to effect a return and decided to outland. A paddock was chosen which appeared suitable and provided a good landing run into wind. However the paddock had been ploughed and grass had grown to 0.3 metres high. Following touchdown well into the field the combination of rough ground medium high grass and heavy braking caused the glider to ground loop breaking the rear fuselage as it did so. This accident was not the subject of an on-site investigation.

The helicopter had been transported by road to Schofields to form part of the static display associated with an air show. Although it was airworthy, the helicopter was the only one of its type in the country and had not been approved for flight at the show. At the conclusion of the show, one of the persons responsible for the restoration of the aircraft became concerned for its security, and he elected to hover taxy the helicopter a short distance onto Naval property. He had never received any formal helicopter flying instruction and control of the aircraft was lost shortly after it became airborne. The helicopter struck the ground while moving backwards and came to rest on its side some 60 metres from the parked position.

The particular aircraft is a glider fitted with a retractable engine. Shortly after takeoff for a soaring flight, the pilot noticed that the airspeed indicator (ASI) appeared to be operating erratically. The flight was continued with the pilot estimating the airspeed, but no thermals were found and the pilot decided to return to the departure point using engine power. The aircraft stalled during the landing flare and the left wing struck the ground. The aircraft slewed to the left and touched down while travelling sideways. The fuselage was fractured during the ensuing ground slide. The approach was flown with landing flap and a substantial degree of air-brake deployed. With the engine also extended the glider was in an extremely high drag situation. Although the flight manual is specific about the degradation in performance of the glider with the engine extended, the pilot reported that his endorsement training failed to adequately address this aspect. Investigation also revealed that some dirt and insects were present in the pitot/static plumbing connected to the ASI. These may have caused the reported erratic readings during the initial stages of the flight.

Circumstances:

The occasion of the flight was a photographic shoot to illustrate a pilot's perspective while spinning an aircraft. The pilot had recently completed a course on aerobatics and spinning. At 6000 feet he commenced the entry to a left spin, using the technique taught by the school. After about one and three quarter turns, when the spin appeared 'unusual', he decided to recover, releasing the control column and applying full right rudder. He then noticed the airspeed increasing at an alarming rate but was unable to stop the rotation. The airspeed rapidly increased through maximum permitted airspeed to 180/190 kts, at which point the pilot centralised the controls. The aircraft stopped rotating and the pilot recovered from the dive at about 700 ft agl. He then noticed severe overstress wrinkling on both wings and elected to carry out an immediate power-off emergency landing. The aircraft suffered further damage when it struck a small embankment during the landing roll. The wing damage indicated a rolling overstress consistent with a high speed spiral dive to the right. After analysis and experimentation, the pilot's chief flying instructor was able to reproduce the symptoms and concluded that control relaxation at a critical time in the spin entry resulted in a reversal of direction from a 'left spin' to a very steep and rapid spiral dive to the right. Due to the nature of the rotation, the pilot had not been able to identify the direction.

Circumstances:

An approaching front was causing the wind to swing from a 45 degree headwind/crosswind to a 45 degree tailwind/crosswind from the left. Although the pilot reported that he considered that the conditions were not suitable, he decided to attempt a take-off as he felt there was a pressing need to carry out a survey of his property. Just prior to lift off, the aircraft veered to the left and the nosewheel entered a soft area at the side of the strip. The nosewheel broke off and the aircraft cartwheeled across the paddock. The pilot had completed a rotorcraft pilot's course, consisting of 10 hours of instruction, and the first 10 hours of post course consolidation. However, the pilot had very little experience at operating a rotorcraft in fluctuating crosswind conditions. The loss of control was probably the result of a sudden wind change during the latter part of the take-off roll and pilot inexperience.