The pilot and passenger were conducting inspections at various company facilities in the area. They had landed at a drilling site for an inspection which lasted over one hour. After a routine start-up and lift-off to a low hover, the helicopter commenced to move forward but the main rotor blades struck the ground.

The pilot considered that he had been unable to obtain correct cyclic control response during the take-off. No faults were found to indicate a control problem, although some parts at the top of the mast were substantially damaged during the accident.

The aircraft was to take off from Lindeman Island. The strip was reported as being a bit rough. The pilot held the control column full back during the take-off run, however the nose gear struck the ground three or four times. As the aircraft speed approached take-off speed the nose gear collapsed, and the aircraft skidded to a halt in a nose-down attitude.

During climb out of Sydney the left engine oil pressure warning illuminated, associated with a falling oil pressure indication. The left engine was shut down. ATC were advised of the problem and the aircraft returned to Sydney where an uneventful single engine approach and landing was carried out. Investigation revealed the rear bearing oil scavenge line was cracked and the rear turbine blades showed evidence of foreign object damage. Engine strip revealed a low pressure turbine blade had failed from fatigue. There is an improved blade assembly now available which the operator is using to upgrade the fleet.

Shortly after take-off, whilst climbing through 6000 feet, the left AC generator light illuminated and could not be reset. A loud vibration was heard and felt from the left engine. Visual inspection revealed black smoke coming from the generator vent, and remnants of red hot generator windings against the grill of the vent. There were no fire warnings but the engine was shut down to prevent further damage. The aircraft returned to Sydney where an uneventful single engine landing was carried out. Examination of the generator revealed that the drive end bearing had failed, allowing the rotor to contact the stator. The drive shaft however was reported to be in good condition, having failed to shear and disconnect the generator from the engine as intended. This matter has been referred to the Civil Aviation Authority for resolution with the manufacturer to ensure that the design of the generator drive shaft is suitable for the application.

Approaching the top of climb the left engine began to surge moderately. Engine temperature and pressure appeared normal. Although the pilot carried out trouble checks the surging continued and moderate vibration was noticed. The pilot decided to return to Sydney, but two minutes later an audible 'crack' was heard from the engine. The propeller was feathered, the engine secured, and the aircraft continued to Sydney for an uneventful single engine landing.

It was later determined that the left engine crankshaft had suffered a fatigue failure at the forward crankweb. The shaft was on its second life and had completed 265 hours since the engine was last reconditioned. No rework had been performed on the shaft during reconditioning.

Factual Information

All times are UTC.

VH-FCE [E110] departed Coffs Harbour for Williamtown at 0223 hours and climbed to cruise at 10,000ft.

VH-NID [DHC8] departed Port Macquarie for Sydney at 0244 hours and was on climb to FL180.

The tracks of the two aircraft crossed approximately 15 nm south-west of Port Macquarie and as the crew of FCE were performing a standard lookout scan they noticed NID climb through their level while crossing from left to right. It was estimated that the aircraft passed approximately 1000m from each other.

The crew of NID did not see FCE as they were passed that aircraft before the conversation between FCE and Sydney FS alerted them to the situation.

The weather conditions were approximately three to four octa of cloud with visibility in excess of ten kilometres.

The Sydney FSO failed to identify the confliction even though all the pertinent information was available and both aircraft made all the correct frequency transmissions. No traffic information was passed to either aircraft prior to the occurrence.

The FSO stated that certain personal problems were causing some preoccupation.

The flight was enroute from Brisbane to Cairns and at 1118 hours Eastern Standard Time, the pilot contacted Cairns Approach. The aircraft was on descent to 7,000 ft on the Cairns VHF Omni Range (VOR) 153 radial, and the approach controller then cleared the aircraft to descend to 3,000 ft not below the Distance Measuring Equipment (DME) Arrival steps.

After receiving the initial clearance, the pilot asked for confirmation of the clearance, and, at 1119 hours, the controller repeated the descent clearance, "cleared to three thousand not below the DME steps" which the pilot acknowledged.

Approximately two minutes later the approach controller noticed on the radar display that the aircraft was descending below the DME steps and immediately asked the pilot for his inflight conditions. After a short delay the pilot reported that they were visual, and the controller then cleared the aircraft to descend to 3,000 ft visually. The aircraft landed at Cairns without further incident at 1132 hours.

The captain was a training captain and was acting in this capacity in the left hand control seat. He had decided to execute a straight in approach for runway 33 to save time, although the prevailing wind favoured runway 15. The Automatic Terminal Information Service (ATIS) indicated the surface wind was from the southeast at 10 to 15 knots, altimeter setting (QNH) 1014 hectopascals, temperature 29 degrees Celsius, one octa of cloud at 2,500 ft, two octas of cloud at 3,000 ft, and visibility 30 kilometres.

The captain was operating the aircraft radio, and when he obtained the clearance from Cairns Approach, interpreted the clearance to mean that the aircraft was required to maintain 1,000 ft above the Control Area (CTA) steps, as they were not making a DME arrival. (The CTA steps mark the lower limits of controlled airspace.) The descent, below 7,000 ft, was being conducted on this basis, maintaining at least 1,000 ft above the CTA steps.

When the controller asked the pilot to report in-flight conditions, the second officer was unable to see Cairns due to a small amount of cloud ahead, and this resulted in a 30 second delay before the crew was able to report visual.

The co-pilot was acting in the capacity of safety pilot and was occupying the right hand observers' seat. He did not have a DME Arrival chart available for reference and was not monitoring the approach. The duty of the safety pilot is to provide backup support for the captain when the second officer is the pilot flying. There were no specific procedures defining the duties of the safety pilot under the existing circumstances.

The second officer was undergoing training for an upgrade to co-pilot and was in the right control seat. He was the pilot flying and had briefed the crew for a DME Arrival at Cairns followed by a visual approach and landing on runway 15. The DME Arrival had been entered in the Flight Management Computer but was later deleted when the captain rebriefed for a straight in approach for runway 33 providing the downwind component did not exceed the limit of 15 knots. A left circuit for runway 15 would be carried out if the downwind component was above this limit.

The second officer disconnected the autopilot at 7,000 ft and was hand flying the aircraft to become better accustomed to the feel of the controls prior to carrying out the landing. He had the DME Arrival chart available on his chart holder but did not refer to it as he was preoccupied with flying the aircraft. The second officer was aware that the captain was referring to the Cairns Area chart. The captain had read out distances and altitudes, and the second officer had assumed they were DME distances and altitudes corresponding to the DME Arrival steps.

CONCLUSION

Findings

1. The captain misinterpreted the terms of the clearance.
2. The captain was not familiar with the term "not below the DME steps" and incorrectly associated it with the CTA steps which in some instances are below terrain altitudes.
3. The second officer did not cross check, and wrongly assumed the information given to him by the captain was valid for the descent.
4. The co-pilot had not been adequately briefed by the captain as to his role and responsibilities during the approach and took no active part in it.

Significant factors

1. The captain misinterpreted the terms of the airways clearance.
2. The co-pilot was not monitoring the approach and was not adequately performing his role as safety pilot.
3. The second officer did not cross check the DME Arrival chart and assumed that the information given by the captain was correct.
4. The aircraft was descended below the DME steps in an area of high terrain.

The pilot had been authorised to conduct a solo navigational exercise as part of a commercial pilot licence course. The authorisation did not include the three passengers, two of whom were trainees from the same training facility as the pilot. The flight was planned to track from Cessnock to Tamworth for a landing, then Gunnedah to refuel before returning to Cessnock.

The flight progressed as planned to Tamworth where the fuel quantity was visually confirmed adequate for the next leg to Gunnedah. At Tamworth, the pilot discussed with the front seat passenger the possibility of performing a simulated engine failure in cruise using the fuel selector to fail the engine. The passenger stated that, as he considered this to be unsafe, he would simulate an engine failure by retarding the throttle only.

The pilot reported that during cruise at 6,500 ft, after departing Tamworth, the front seat passenger retarded the right engine throttle to simulate an engine failure. The engine failure procedure was performed by stating the actions and touching, but not manipulating, the appropriate controls. Power was then restored to a normal cruise setting.

Later, whilst passing through 5,000 ft on descent into Gunnedah, the right engine began to run roughly, and the aircraft yawed to the right. The pilot carried out system checks, including repositioning the throttle to achieve the smoothest operation. He did not shut down the engine, as he considered it to be capable of producing some power. The descent continued to the circuit area, which was entered on the crosswind leg for runway 11. A strong southerly wind was noted. The landing gear was extended at about mid-base leg. A normal circuit was flown until the turn onto final at about 400 feet AGL when the aircraft encountered turbulence and overshot the runway extended centreline. The pilot applied power to go around. However, the aircraft yawed to the right and continued to descend. The landing gear was retracted but the aircraft performance did not improve. Both engines were shut down and an emergency landing was carried out off the aerodrome. The occupants evacuated the aircraft through a shattered side window.

Investigation revealed that the right engine carburettor bowl and its supply line contained no fuel, but there was ample fuel in the right tank. As there was no physical damage to the bowl or line which could have allowed the fuel to leak away, it was concluded that the right engine fuel supply had been selected off some time prior to the accident.

The front seat passenger later stated that he had failed the right engine by selecting the fuel off some time prior to the aircraft entering the circuit. It was determined that the aircraft, as configured, was not capable of maintaining height and that the pilot had misjudged the circuit and approach. It is likely that the aircraft was positioned low and too far from the runway threshold as it overshot the turn onto final. The subsequent attempt to go around was unsuccessful because, with the landing gear extended and the right propeller windmilling, the aircraft had no climb capability. The pilot stated that he had continued with the approach as he believed that the right engine was capable of delivering some power if required.

Significant Factors

1. An engine failure was simulated by turning off the fuel to the right engine.

2. The right propeller was not feathered.

3. The pilot misjudged the circuit and approach to land and attempted to conduct a go-around.

4. The aircraft, as configured, was not capable of maintaining height.

The helicopter was engaged in spraying herbicide along levee banks. The pilot tracked the helicopter along the top of the banks to minimise spray drift onto adjoining cotton crops. It was necessary for the pilot to look monetarily behind the helicopter to check the spray drift. On looking forward the pilot noticed power lines immediately in front of the helicopter under the rotor disc. He said there was no time to take evasive action. After the collision with the power lines, control of the helicopter was lost and it impacted the left side of the levee bank.

On the morning of the accident the aircraft which had been leased from another company, completed a scheduled service from Brisbane to Lord Howe Island. The crew reported all aspects of the aircraft operation were normal. In accordance with company procedures the co-pilot was the last to board the aircraft for the flight to Sydney and he closed the cabin door. He reported all visual indications showed the door locks were properly engaged. After take-off passengers seated near the rear of the aircraft reported a very loud whistling noise from the area near the rear cabin door. During the climb to FL180 cockpit instruments indicated a cabin pressurisation leak with the pressurisation system unable to maintain a cabin pressure differential greater than 3.8 lb/sq in. The pilot in command identified the problem as being a faulty main cabin door seal. About 30 minutes before commencing descent to Sydney, he inspected the door and observed the leak to be in the vicinity of the top right hand corner of the door. He partially plugged the gap between the door and fuselage with rags and plastic sheeting which reduced the noise created by the pressurisation leak.

A passenger seated close to the door was moved to a seat closer to the flight deck where it was less noisy. Following receipt of clearance to descend to 7000 ft, descent was commenced at 70 NM from Sydney in accordance with the normal flight profile. During the descent, as the indicated airspeed (IAS) was increasing through 200 kts at FL170, a loud bang was heard and the cabin rapidly depressurised. The pilot in command disengaged the auto pilot and conducted an emergency descent to 11,000 ft. After donning his oxygen mask, the co-pilot advised the pilot in command that the cabin door had separated from the aircraft. He also noted that the oxygen masks had dropped from the roof of the passenger cabin and some passengers had placed the masks to their faces. During the investigation the passengers reported they had been unable to obtain any flow of oxygen from the masks. The pre-take-off safety briefing did not include instructions on the use of oxygen masks, nor did the safety-on-board briefing card describe the requirement to pull on the mask to commence the flow of oxygen. The pilot in command did not don his oxygen mask given the relatively short period of time in the descent. Approaching 11,000 ft he reduced the rate of descent and carried out a handling check at 160 kts IAS. Apart from the increased slipstream noise aircraft operations appeared normal.

The crew advised air traffic control that they had a pressurisation problem but did not declare an emergency. The aircraft proceeded to Sydney and landed without further incident. The door separated from the aircraft about 65 NM NE of Sydney. It did not strike the rear fuselage or tailplane as it departed the aircraft and damage to the aircraft was confined to the door lower latches and the hinge. The damage to the latches was consistent with the lower horizontal pins being fully engaged at the time. There was no damage to the latches of the upper horizontal pins, nor the top hook latches. It is possible that a material failure of the internal locking mechanism occurred during the flight which permitted the upper latch pins and hooks to release. Under the increased air loads during the descent, the door separated from the remaining attachment points. The door was not recovered and the reason it separated from the aircraft has not been determined.

SAFETY ACTION

As a result of this investigation the Bureau issued safety advisory notice SAN10192 to all Beech 200 operators on 23 October 1992. The SAN provided the Beech 200 operators with preliminary information of the occurrence. On 28 October 1992 the Bureau issued interim recommendation IR9221045 to the Civil Aviation Authority.

It stated: That the Civil Aviation Authority:

1. Advise all Beechcraft King Air series operators of the circumstances of this in-flight separation of a cabin door from a Beech 200 series aircraft.

2. Implement the requirement for an initial engineering inspection of the cabin air stair door locking and latching mechanisms paying particular attention to the following points:

(i) integrity of the inner (upper) door handle sprocket braze assembly;

(ii) the condition, assembly and rigging of chain and sprocket mechanisms;

(iii) the latches, hooks, rollers and their pivot pins;

(iv) rigging, operation, lubrication and correct indication of handles and latch pins; and

(v) any abnormal loads required to operate the handles arising from possible door and/or hinge distortion.

3. In consideration of the inspection reports, urge the manufacturer to introduce repetitive inspection requirements to ensure door mechanism integrity.

4. Ensure that operator's systems of maintenance reflect relevant inspections at appropriate intervals to maintain door integrity. The CAA issued Airworthiness Directive AD/Beech 200/53 in response to IR9221045.

The Bureau has classified this response as CLOSED/ACCEPTED.