Forced/precautionary landing

During a property inspection prior to commencing spraying, the engine failed. The helicopter was about 700 ft above ground level at the time. The pilot attempted to dump the load by the electrical system, but this failed to operate. He was too occupied to operate the mechanical dump system.

During the subsequent landing, the helicopter rolled onto its side after a cross tube on one side failed. The failed area had been weakened by corrosion and there was evidence of pre-existing cracks. The engine crankcase was fractured, consistent with a connecting rod failure at no. 5 cylinder. Logbook records indicated that the engine had been over-sped some 200 operating hours earlier. A faulty canon plug had prevented the electrical dump system from operating.

The pilot reported that the engine stopped in the cruise at about 600 ft. He entered autorotation and landed in low trees and scrub. The engine stopped because the crank shaft drive gear bolt failed due to hydrogen embrittlement. When the bolt failed drive to the accessories was lost. The manufacturer has verbally assured CASA that this was an isolated instance of a bolt failure.

While returning to the airstrip to reload for another spray run, the aircraft experienced severe engine surge with associated rough running. The pilot selected the fuel boost pump on, but with little improvement. He then elected to make a forced landing. While stretching the glide, the aircraft stalled at about five feet AGL and landed heavily in a soft earth paddock. This resulted in the left main landing gear failing, followed by the nose impacting with sufficient force to tear the engine from its mounts. Inspection by the company found the main fuel filter not lock wired allowing the filter assembly to come loose and starve the engine of fuel.

During the initial climb after take-off from Runway 07, the pilot saw a large white bird in front and just right of the aircraft. With the aircraft only 50 ft above the runway there was insufficient airspace and time to take avoiding action. The windscreen shattered and shards of Perspex flew around the cabin. The pilot closed the throttle immediately and landed the aircraft on the remaining section of runway.

After taxying clear of the runway, the pilot shut the engine down and attended to a young boy who was seated in the right rear seat. He had been injured by the flying Perspex and was bleeding profusely from a cut above his left eye. The boy later received stitches at the Redcliffe Hospital.

During an inspection of the runway, Perspex pieces and the remains of an Ibis were found 400 m from the threshold.

The MD500 helicopter was engaged in a sling operation to lift a powerline to the top of a transmission tower. The pilot was hovering the helicopter about 60 ft above the 30-ft tower, and had just passed the powerline to the linesman when the engine began to "spool down", resulting in a total loss of power.

The pilot immediately banked the helicopter to the right to avoid personnel on and below the tower, and attempted a landing in light scrub. However, the helicopter came to rest on its right side, incurring substantial damage, and slightly injuring the pilot. The maintenance investigation found that the engine fuel system was contaminated with water, discoloured fuel, and particle debris. After the engine fuel system was cleaned, the engine was successfully ground-run.

The helicopter had spent 45 hours on firefighting duties in the 60 hours since the last maintenance inspection. During the firefighting operations, refuelling was routinely undertaken from an assortment of drum and mobile bowser fuel sources. "Hot" refuelling also accounted for a significant proportion of these refuelling operations. It is probable that the fuel system was contaminated during those refuelling operations.

SAFETY ACTION STATEMENT

As a result of this occurrence, the Bureau of Air Safety Investigation is currently analysing a possible safety deficiency. The deficiency identified involves the manufacturer-instigated modification of the fuel filtration system which removed the ability to do water/contamination tests at the engine driven fuel pump and filter assembly. Any recommendation issued as a result of this analysis will be published in the Bureau's Quarterly Safety Deficiency Report.

Soon after the helicopter had left Moomba on a charter flight to Whanto, the pilot reported hearing a loud bang and noticed that the rear left door of the aircraft, and associated pillar, were missing. The pilot reduced power, confirmed that his passengers were safe, and checked that the flight controls and systems were performing normally before turning to land at Innamincka Station homestead.

The helicopter landed without further incident. After shutdown, the missing door was found impaled upon the horizontal stabiliser. The helicopter was configured to carry a stretcher by incorporating an approved kit, in accordance with Bell Service Instruction No. 206-68. With the kit correctly fitted, the co-pilot door could not be closed unless the pillar-locking handle was in the locked position. An additional safeguard of the system was that when the co-pilot door was closed and locked, the pillar-locking handle could not be moved to the unlocked position.

Following the accident, the operator found that the stretcher pillar had unlatched in flight. An inspection revealed that the locking handle was in the unlocked position. However, the locking handle had been installed 180 degrees from the correct position, circumventing defences designed to prevent the helicopter departing with the pillar unlatched or being unlatched during flight.

LOCAL SAFETY ACTION

The operator has advised the Civil Aviation Safety Authority of possible shortcomings in the flight manual supplement, with regard to the correct operation of the litter kit. The operator has also incorporated a modification that includes a safety latch, preventing the pillar-locking handle from being incorrectly installed.

The Piper Cherokee Lance (PA32R-300) was prepared for departure from runway 35 at Essendon for a flight to Moorabbin, Phillip Island and return. The outside air temperature was 29 degrees C and the wind was from 320 degrees, gusting between 15 and 25 kt. This resulted in a crosswind of 12 kt and a density altitude of approximately 2,000 ft.

The pilot decided to conduct a flapless take-off. He had used this take-off configuration successfully on previous departures from Essendon. The pilot reported that during the take-off roll the aircraft accelerated normally and the engine reached its maximum power indications of 2,700 rpm and 27 in of manifold pressure. As the aircraft lifted off at an airspeed of approximately 65 kt the right wing dropped suddenly, and the aircraft yawed to the right. The pilot corrected the wing drop and the yaw but then realised that the aircraft was not climbing normally. With maximum power still being applied, the airspeed was still indicating 65 kt.

The pilot retracted the landing gear when he had insufficient runway remaining on which to land and advised ATC that he had a problem. When the tower controller observed the aircraft at a very low altitude and flying towards a series of high-tension powerlines, he activated the 'common-crash' alarm.

The pilot was able to fly the aircraft over the high-tension powerlines at the lowest point of the span, which meant that the aircraft was below the height of the pylons. He stated that he felt the aircraft seemed to be having difficulty remaining airborne and that it only felt normal when he lowered the nose attitude. However, he then had to raise to nose attitude to climb over obstacles. He carried out relevant checks but was not able to identify any problems that may have affected the aircraft's performance.

The pilot was able to keep the aircraft flying until he reached a large paddock suitable for a forced landing. He applied two stages of flap and extended the landing gear for the landing. The surface of the paddock was very rough and sloped downhill from the touchdown point. The pilot was not able to stop the aircraft before it continued across a low embankment and through a fence. The aircraft was substantially damaged. The pilot and his two passengers were not injured and were able to evacuate the aircraft without assistance.

The investigation did not find any evidence of a malfunction with the aircraft, the engine, or associated systems. However, it was found that the elevator trim was in the full nose down position and that the rudder trim was full nose left. This flight was the first after a periodic maintenance check had been carried out. It is likely that the trims were not returned to neutral following the maintenance, and this was not noticed by the pilot during his pre-take-off checks.

At the take-off weight of approximately 1500kg the PA32R-300 flight manual charts indicate that the take-off safety speed (TOSS) for the aircraft is 72 knots. The nose attitude is required to be raised smoothly for a flapless take-off, and the aircraft accelerated to a minimum of 72 knots, before the pilot adopts the appropriate attitude to attain a climb speed of 92 knots.

It is likely that the aircraft was adversely affected by a gust of wind as it lifted off. In addition, the incorrect trim tab settings would have resulted in the aircraft flying in an unbalanced condition. This imbalance would have produced extra drag with a resulting reduction in airspeed. To correct the wing drop and yaw the pilot would have had to promptly apply coarse control inputs. Drag would have further increased, with a corresponding reduction in airspeed. It is probable that the aircraft did not have sufficient power to overcome the drag resulting from the low speed and high nose attitude - a condition commonly known as 'flying on the back of the drag curve'. The density altitude and high temperature on the day would have also adversely affected the aircraft's performance.

The instructor pilot reported that the take-off roll, and climb were normal until the left crosswind turn at about 600 ft when the engine lost power and RPM decreased to between 1600 and 1900 RPM. Trouble checks were carried out and a turn towards the airfield as commenced. However, due to the distance from the airfield and bordering powerlines a glide approach was not possible. A 300 m long clearing was selected for a landing and the aircraft impacted with some small saplings. The aircraft was vacated once stationary, and no injuries were sustained by the crew.

The helicopter was involved in bushfire control when the pilot reported that the engine suddenly lost power at a height of about 150 ft above trees. Attempts to restart the engine were unsuccessful and a forced landing was carried out amongst small trees. Substantial damage was incurred during the forced landing and the pilot sustained minor injuries. The helicopter was subsequently destroyed by the bushfire.

The pilot later reported he had refuelled the helicopter with 300 lbs of fuel about 15 minutes before the accident. Fuel checks at the time indicated that the fuel was not contaminated. The remainder of the fuel, the fuel filter and refuelling equipment at the base, were subsequently checked after the accident and were reported to be clean. As the engine was extensively damaged by the bushfire, the reason for the failure was not determined.

The pilot was conducting a scheduled freight run and earlier that day had refuelled the aircraft and departed Bankstown with full main tanks (401 litres) and 160 litres in the auxiliary tanks. The accident flight was on the Scone to Maitland sector, and the pilot reported that when departing Scone, the aircraft had about 108 kilograms of freight and 430 litres of fuel.

The pilot reported that while on descent and at about five miles from Maitland, the right engine RPM began to fluctuate with an accompanied increase in vibration. The pilot, thinking that it was a malfunction of the propeller governor, reported that he shut down the right engine and selected the right propeller to feather.

The pilot observed that the right propeller was still windmilling, the indicated airspeed was decreasing and that the aircraft was unable to maintain height, so he elected to land in a nearby field. He closed the left throttle and selected the landing gear down. The landing gear collapsed on touchdown as there had been insufficient time for it to extend and lock. The aircraft slid for about 120 metres.

Investigation of the fuel system indicated that the auxiliary tanks were empty while the main tanks each contained about 140 litres. The cockpit fuel selectors indicated that the main fuel tanks were selected.

Investigation of the engines and their systems, including the propellers and governors, could not determine the reason for the reported propeller malfunction or the inability of the aircraft to maintain height.