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.

The aircraft had departed from runway 11L for a dual instructional flight to the local training area. Late on the downwind leg, when the aircraft was slow to reach the required 1,500 ft, the Tower requested the aircraft to maintain 1,000 ft due to incoming traffic. Soon after, the aircraft experienced a partial loss of engine power, and the instructor reported he was returning to the aerodrome. Almost immediately after this radio call was made, the engine failed completely. The instructor made a brief Mayday call then turned right towards a park, as he was unable to reach the aerodrome. The aircraft overshot the park, striking a light pole which severed the left wing. It then rolled to the left, struck a mesh fence, and came to rest on its side in a carpark, with the right wing under a parked car.

Examination revealed that the left exhaust stacks had separated from the muffler. Leaking hot exhaust gas had then burned through the cowling and also burned the insulation from electrical wiring, including the magneto switch wires which shorted to ground, resulting in a complete loss of engine power.

Why the clamping hardware for the exhaust stacks separated was not determined. However, the hardware, consisting of a clamp, bolt and two plain nuts which form a locknut when tightened against each other, operate in a harsh environment. Should any of the nuts become loose it is likely that engine vibration would rapidly lead to separation of the exhaust system.

The densely populated area, over which the aircraft was flying when the engine failed, was unsuitable for a safe forced landing.

Significant factors

1. The engine exhaust clamp bolts worked loose, and the right exhaust pipes separated from the muffler.

2. Escaping exhaust gases caused damage to the magneto wiring insulation, resulting in the loss of the ignition source and loss of engine power.

3. The aircraft was over an area which was unsuitable for a successful forced landing.

SAFETY ACTION

As a result of the investigation into this and a similar occurrence (OASIS 9400441) The Bureau of Air Safety Investigation met with the Civil Aviation Authority Airworthiness (Powerplants) staff and discussed the apparent deficiencies with the exhaust clamping arrangements.

The CAA researched the available data and located a SOCATA Service Bulletin (SB), SB 10-073-78, which had been released in January 1994. The CAA subsequently issued Aerospatiale (SOCATA) TB9, TB10 and TB20 Airworthiness Directives (ADs) AD/TB10/20, AD/TB10/21 and AD/TB20/27 effective 26 May 1994 mandating compliance with the manufacturers SB within 50 Hours time of service.

This prompt action by the CAA, in full consultation with the Bureau of Air Safety Investigation, obviated the need for any formal safety output.

The private pilot conducted a daily inspection, loaded five people and luggage on board the aircraft and attempted a take-off on runway 17 right. When the aircraft failed to rotate, the pilot rejected the take-off. He attempted a second take-off on runway 17 right, using the extra runway distance available before the displaced threshold. Again, the aircraft failed to rotate, and the take-off was rejected. He taxied back to dispersal, unloaded 75 kilograms of luggage, and attempted a third unsuccessful take-off. Next, he unloaded the four passengers and attempted a fourth take-off which was also rejected. The pilot taxied back to dispersal and acquired the services of a flying instructor in an attempt to determine why the aircraft would not rotate when he pulled the control column back.

The instructor agreed to fly a circuit with the pilot. The pilot carried out a take-off with the instructor monitoring. Because the instructor was not flying the aircraft he was not aware that the pilot had to apply stabilator back trim to rotate the aircraft. During the crosswind leg the instructor noted that the pilot was holding an unusual control column position to achieve the climb attitude. The instructor took over the controls but realised that, although the control column pressures felt normal and ailerons performed normally, there was little, or no attitude change when the column was pushed forward or pulled aft.

Using engine power variations and stabilator trim, the instructor carried out a long, shallow, landing approach for runway 17 right. The instructor was unable to reduce the rate of descent enough to prevent a hard landing. On touchdown the right main landing gear leg broke and the aircraft skidded off the runway to the left.

It was subsequently found that stabilator control was lost because the torque tube lever (drive horn) slipped on the stabilator torque tube. There was evidence of lubricant between the clamping surfaces of the drive horn and the stabilator torque tube. Lubricant had been applied to the area during recent assembly in an attempt to prevent corrosion which had occurred in the past on an unpainted torque tube. Lubricant may also find its way onto the torque tube/drive horn when the jack screw, which is located immediately above the drive horn, is lubricated.

The rigging screw/safety screw, which located the drive horn on the torque tube, had sheared progressively. It was estimated that this screw will shear with a control force of 60 pounds.

A series of tests was carried out to measure the breakaway and sliding forces of the drive horn on the torque tube with the drive horn clamp bolts properly torqued between 50- and 70-inch pounds. These tests were conducted without fitting a rigging screw. With lubricated surfaces, the maximum breakaway force was 96 pounds with the clamping bolts torqued to 70-inch pounds. The breakaway force fell to 45 pounds with clamping bolts torqued to 50-inch pounds. The highest breakaway force measured during the tests was 165 pounds with dry surfaces and 60-inch pounds torque on the clamping bolts.

These tests indicated that the current design does not comply with FAR 23.397 standards because the control system is not capable of transmitting a force of 200 pounds to the stabilator without risk of slippage of the drive horn on the torque tube.

The rigging/safety screw probably failed as a result of being subjected to repeated shearing forces during flight.

Significant Factors

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

1. The pilot(s) conducted repetitive rejected take-offs rather than seek qualified engineering advice.
2. Because of the current design of the attachment of the drive horn to the stabilator torque tube, the control system does not comply with FAR 23.397 standards in that it is not capable of transmitting a force of 200 pounds to the stabilator without the risk of slippage of the drive horn on the torque tube.
3. The friction grip surfaces between the drive horn and the torque tube had been lubricated during installation thereby making slippage of the drive horn more likely to occur.
4. It is possible that lubricant may find its way onto the torque tube/drive horn area because maintenance engineers periodically lubricate the screw jack located close to and above the drive horn.

Safety Action

In response to preliminary investigation advice, the Civil Aviation Authority issued Direct Mail Airworthiness Directive AD/P68/38 in March 1992. This directive required initial and repetitive integrity inspections of the stabilator drive horn to torque tube clamped joint.

AD/P68/38 Amdt 1 was issued 6/92 to reflect and require compliance with Partenavia Service bulletin P68-87. This amendment aligned the Australian AD with the country of origin AD FAI 92-077 requirements.

The current AD/P68/38 Amdt 2, issued 9/92, reflects and requires repetitive compliance with Partenavia SB P/68-87 rev 1 which introduces a more specific clamp bolt torque and a new safety screw of a different material.

The Bureau of Air Safety Investigation engineering evaluation and testing of the stabilator horn to torque tube clamped joint, contends that the design fails to meet the FAR 23 design standards. Further comparisons, between the BASI engineering report and tests and the Partenavia engineering tests revealed that, when the joint was lubricated it failed to transmit limit loads and raises doubts whether the new NAS1105 safety screw by itself is capable of transmitting the limit load with a factor of 1.5 as suggested by Partenavia.

The Bureau of Air Safety Investigation therefore makes the following recommendation:

R940071

1. That the Civil Aviation Authority review the Partenavia engineering   data (in comparison to the BASI engineering reports) to ascertain whether or not this friction clamped joint meets the FAR 23 design standard.
2. That the Civil Aviation Authority continue to negotiate with the manufacturer to produce a scheme for this primary control which positively attaches the Torque Tube Lever (Drive Horn) to the Stabilator Torque Tube.

While enroute from Darwin to Maningrida at 9000 feet and at 12nm NE of Nabarlek, the pilot, who was the sole occupant, noticed a drop in the starboard engine manifold pressure.

He looked at the engine and saw smoke coming out of the right hand side inspection vent. The manifold pressure had fallen to 15in Hg and by this stage, oil was starting to leak from around the starboard engine cowl at a considerable rate.

The pilot carried out the 'engine fire' procedure drill and secured the engine, advised ATC and diverted to Nabarlek for landing. The propellor continued to windmill with the pitch lever in the feathered position until the aircraft speed reduced to 90 knots IAS on final. The propellor appeared to be about 90 % feathered. The aircraft landed safely.

Engine damage was caused by failure of the crankshaft counterweight flange allowing the counterweights to separate. The crankcase was damaged resulting in a severe oil leak onto the turbocharger causing the smoke seen by the pilot.

The pilot of VH-LQA was conducting a practice ILS approach for runway 23 at Adelaide Airport. Approaching the localizer (LLZ) at 3000ft air traffic control (ATC) instructed him to enter a holding pattern between 28 and 34 km north-east of Adelaide to maintain horizontal separation standards with VH-YMJ, which had been cleared by ATC to intercept the 23 LLZ at 3000ft, from the east, for its arrival to Adelaide.

After completion of the holding pattern, and not having received any further instructions from ATC, the pilot of VH-LQA believed he could continue the practice ILS without any further clearance and intercepted the LLZ.

He was instructed three times in quick succession to turn right onto a heading of 310 degrees, and the pilot of VH-YMJ was instructed to continue turning left. The two aircraft passed at the same height with less than 5km horizontal separation.

During the take-off sequence the nose locker door, which had not been correctly secured, came open and separated at the hinge line.

The door was struck by the left propeller, damaging the blades. The door became lodged on the leading edge of the left wing and the pilot abandoned the take-off. The subsequent landing was heavy.

In addition to the damage caused by the door, the wings were twisted and the lower wing skins rippled during the heavy landing.