Circumstances

Singapore Airlines Flight 222 [SIA 222] had departed Sydney for Singapore at 1548 hours EST and passed over Darwin at Flight Level [FL] 370. As this level was non-standard and the aircraft was going to enter Indonesian airspace, the crew were asked if they could accept climb to FL390 [a standard level] prior to the boundary position [KIKEM]. When the crew replied in the affirmative, Darwin ATC issued a clearance for the aircraft to climb to FL390 with a requirement to reach that level by KIKEM. This instruction was issued at 1918 hours CST and was clearly and correctly read back by the crew.

Darwin ATC coordinated this information with Bali ATC as per the coordination agreement between Australia and Indonesia.

At 1935 hours SIA 222 reported at the position prior to the boundary [SATKO] at FL370. No mention of FL390 was made at this time by either the crew, or ATS. Perth FS instructed the crew to contact Bali control at KIKEM. Because ATS did not mention or query the crew with respect to FL390, the Captain of SIA 222 became unsure of the validity of the prior clearance and instruction. The flight crew did not question ATS about the clearance.

SIA 222 reported at KIKEM at 1956 hours but the aircraft was still at FL370 in contravention of the ATC clearance received.

Bali control then coordinated with Darwin ATC to confirm the level of SIA 222 and the aircraft was subsequently recleared to FL390.

There was no breakdown in separation.

Significant Factors

1. The crew of SIA 222 became unclear as to the validity of their air traffic control clearance after reporting at SATKO at FL370.

2. The crew of SIA 222 did not make any radio call to clarify the validity, or otherwise, of their air traffic control clearance.

3. The crew of SIA 222 did not reach FL390 by KIKEM which was in contravention of their air traffic control clearance.

Royal Australian Air Force VIP aircraft, call sign NVOY606, was enroute Sydney from Paraburdoo in Western Australia. The aircrew had flight planned to cruise at flight level (FL) 370. However, enroute NVOY606 progressively requested higher levels to FL430. A Melbourne air traffic controller failed to enter the change of level on one of five flight strips. The strip missed was the APOVO position strip which is used for co-ordination with Sydney air traffic controllers. When NYOY606 made a position report at APOVO the pilot reported his actual altitude which was different from the entry on the flight progress strip. This was a chance for the controllers to correct strip entry but at the time the controllers did not react. The altitude error was not discovered until the aircraft was transferred to Sydney control. There was no breakdown in separation with other aircraft.

At the time of the incident, an experienced air traffic controller was undergoing supervised training on Sector 1 (Adelaide to Perth). She failed to make the appropriate entry on the flight progress strip. Air traffic was busy at the time. The supervisor did not notice the oversight.

The Civil Aviation Authority has subsequently conducted an internal investigation. It was noted that the air traffic controller responsible for the oversight had been on duty for three and a half hours without a break. The size of the airspace controlled and the depiction of the route structure on the console was seen as demanding careful attention because, depending on the route, some flights require only two strips whereas others need five. The training officer noted that the short length of cord on his headset did not allow him the freedom of movement he would like when supervising/checking another controller. The controller under training noted that it was difficult to physically move quickly enough when trying to record information received from aircraft because of the size of the display area. The training officer also said that he would like a more elevated chair to enable a better view of the console when supervising.

The headset cord has since been lengthened and a couple of tall chairs have been provided for training officers.

Significant Factors

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

1. A change of level was not transcribed onto a position flight strip by the air traffic controller under training.

2. The training officer did not notice the failure of the controller under training to transcribe the flight level onto the flight progress strip.

3. Neither the training officer nor the trainee reacted to the different flight level reported by the pilot at the APOVO position report.

4. Air traffic was busy at the time of the incident.

VH-IBY and another aircraft VH-LCE were involved in Precision Aerial Delivery System (PADS) training. Two deployments were performed from VH-LCE. On the third drop which was the first drop from VH-IBY, the PADS unit was released from the aircraft, but during the deployment, the static line became detached from the aircraft seat rail attachment point. The crew member who had deployed the PADS became momentarily entangled in the static line and received a minor injury.

On the day of the occurrence the crew had difficulty locating a tiedown fitting which could be attached to the seat track of VH-IBY. The pilot produced a tiedown fitting which was subsequently attached to the left inboard seat rail track about two-thirds of the way forward. The PADS static line was then connected to the tiedown ring with a shackle.

Examination of the tiedown fitting revealed that it failed under applied load.

The tiedown fitting was identified as a Cessna Citation part and when attempts were made to install the same type of fitting onto the seat track of VH-IBY, the tiedown would not fit without spreading the tangs apart. Although the tiedown fitting used was an approved Cessna part, it was not approved for use on Aero Commander 500S type aircraft and therefore it did not fit the seat track profile of VH-IBY.

Safety Action

As a result of the investigation the following Interim Recommendation (IR930090) was made:

That the Civil Aviation Authority amends the wording of the PADS flight manual supplement to reflect specifically how and where the static line is to be secured to the aircraft. If tie down fittings are being used to secure the static line to the seat tracks, then those fittings should be approved and unambiguously identified for use in that aircraft type.

Interchangeability of approved fittings between aircraft of the same type may be compromised by nonstandard seat tracks being fitted into specific aircraft. i.e. Aerocommanders modified to Coastwatch specifications.

The Civil Aviation Authority responded as follows:

'I refer to BASI Interim Recommendation 930090 regarding the Flight Manual Supplement for the Precision Aerial Delivery System.

We do not entirely agree with the BASI Interim Recommendation.

In our view, the primary cause of the incident may have been either an excessively worn seat rail or use of an inappropriate tie down fitting - one neither supplied by the aircraft manufacturer nor locally approved for use in the Aero Commander. Use of improper tie downs in a restraint system will always introduce an unacceptable risk of failure of the system when carrying freight, baggage or any other application of these fittings. Increasing the amount of detail in the Flight Manual Supplement specific to PADS operation is not considered the most efficient means of addressing the problem and will not necessarily achieve the desired aim.

There is no concern that operators will deliberately disregard information relating to attachment of PADS static lines, so the details need only have advisory status. Flight Manuals and Flight Manual Supplements are a means by which the Authority exercises control over mandatory aspects of aircraft operation, but they represent a notoriously expensive and labour intensive activity. As a consequence of the Authority becoming a Government Business Enterprise there is substantial pressure to reduce the reliance on Flight Manual amendments, particularly where they only broadcast general or non-mandatory information.

The Authority is of the view that a more appropriate place for this information is the Operations Manual. These Manuals are readily amended, are familiar to company personnel and can be used to present information specific to individual aircraft and the company’s methods and operations. We will arrange for suitable details to be passed to relevant operators for insertion in their Operations Manuals.'

Status of response:  Closed - Accepted

The aircraft was engaged in aerial mustering operations. Whilst landing to disembark the passenger the pilot experienced intermittent cyclic control problems. He then took off again and during the next 5 to 10 minutes of cattle mustering he tested the cyclic control, but response was normal. A short time later, as the helicopter approached touchdown to re-embark the passenger, all cyclic control was lost. To avoid hitting the waiting passenger the pilot applied power to go around but was unable to control the helicopter's flight path and it impacted the ground nose first.

Inspection of the wreckage revealed that the cyclic control column had fractured at the location of the electrical wiring access hole near the base of the column. The fracture was caused by fatigue crack growth. The access hole had been elongated by mechanical filing and the fatigue origins were located at these abrasion damage sites.

Safety Action

The following interim recommendation was sent to the Civil Aviation Authority on 22 June 1993:

IR930094

That the Civil Aviation Authority advise all operators of this failure and mandate an inspection of the cyclic control column electrical loom access hole to ensure control column integrity.

The CAA in response issued AD/HU-269/102 on 2 August 1993.

Subsequently, results of finite element stress analysis of the failed cyclic pitch control column indicated that material yielding, at the lower electrical loom access hole, occurs below the design limit load. Evaluation of this cyclic control column design is being considered by the Civil Aviation Authority in consultation with the Federal Aviation Administration and the aircraft manufacturer.

When about to turn base for runway 31, the crew of VH-TJQ sighted two light aircraft heading in the opposite direction on the active side of the circuit. From prior communication, the crew of TJQ believed the two aircraft were joining the circuit on the dead side. The pilots of the two light aircraft spoke with American accents and were part of a group visiting Australia. Separation was maintained but it appeared to the crew of TJQ that the pilots of the light aircraft were not familiar with local procedures.

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

• Foreign aircrew apparently unfamiliar with local procedures.

VH-TJQ was cleared to leave controlled area on descent into Ayers Rock. Traffic information on a Boeing 737 taxiing at Ayers Rock for Alice Springs had been passed to TJQ along with advice to contact Adelaide Control passing F200 on descent. TJQ was later told to contact Adelaide Control early because of the departure of the Boeing 737 from Ayers Rock. On contact with Adelaide Control, TJQ was asked to report leaving F200. This was done but the response from Adelaide Control was cut out by another transmission. Direct contact was made with the opposite direction Boeing 737 which was now maintaining F180. TJQ then maintained F190 until the other 737 was sighted about eight miles ahead.

Three aircraft were scheduled to depart Melbourne via the 150 radial. VH-KDK and VH-WZI were vectored left of track to allow the faster aircraft, VH-EWL, to safely overtake both of them. A small closing speed existed between VH-KDK and VH-WZI but normal climb performance was such that vertical separation could be expected before radar separation approached minima. The Departures controller in training decided to place VH-KDK back on pilot navigation by instructing the pilot to track direct to Cowes. This resulted in VH-KDK and VH-EWL now being on gradual converging tracks. The trainee thought that VH-EWL would have drawn in front before both aircraft were back on track. In this configuration the aircraft were handed off to the receiving Inner Sector radar controller who was made aware of the converging aircraft and the possible need to alter one of the aircrafts tracks at a later stage. The Inner Sector controller knew that while the separation minima inside 30 miles was three miles, this increased to 5 miles further out. His judgement was that immediate action was not required but that separation needed to be monitored. The Inner Sector controller became distracted when VH-WZI had not made a radio call when transferred from Departures as well as being distracted by other traffic in the Ballarat/Yarrowee area. When he returned his attention to the convergence of VH-KDK and VH-EWL these aircraft were beyond 30 miles from Melbourne but with only three miles lateral separation. A turn was initiated and the required five miles separation was established. Significant Factors The following factors were considered relevant ot the development of the incident: 1. The Inner Sector radar controller was distracted by other aircraft. 2. The Inner Sector radar controllers scanning of the traffic under his control was inadequate. 3. The Inner Sector radar controller did not ensure that the aircraft remained adequately separated.

The B747 VH-OJD departed runway 34 on runway heading and was cleared to 3000 feet. On contact with Sydney Departures VH-OJD was given a left turn heading 240 and was instructed on two occasions to maintain 3000 feet. The aircraft was observed to climb to 3400 feet, and this was confirmed by the pilot. VH-MZX, a PA31 had departed from runway 07 and had been cleared to 4000 feet on a heading of 030. Horizontal and vertical separation standards were infringed as there was only two miles lateral separation by radar between VH-OJD and VH-MZX. The required separation standards was 1000 feet vertically or three miles horizontally.

After landing on runway 27 the crew of VH-TAD commenced taxiing the aircraft along taxiway echo, back to the terminal. It was necessary to obtain a clearance to cross runway 34 on the way in.

In the control tower the aerodrome controller issued a clearance to another aircraft to take off on runway 34. He also gave approval to the surface movement controller to allow VH-TAD to cross runway 34 behind the aircraft taking off.

The surface movement controller then issued a clearance for VH-TAD to cross runway 34. In doing this he omitted to say to cross behind the departing aircraft. The crew of VH-TAD saw the other aircraft taking off on runway 34 and held VH-TAD short of runway 34 until the other aircraft had passed.

Significant Factor

The following factor was considered relevant to the development of the accident:

1. The surface movement controller incorrectly issued a clearance for VH-TAD to cross runway 34, in lieu of saying to cross behind the aircraft taking off on runway 34.

The pilot was conducting a scheduled passenger service flight from Port Augusta with a stop at Innamincka. A commercial pilot, travelling as a non-paying passenger, occupied the co-pilot's seat to observe the operation. Two additional passengers were on board the aircraft for the entire flight.

After landing at Innamincka, the aircraft was refuelled by the pilot in command and the oil levels of both engines were checked by the observer, who experienced difficulty securing the combination oil filler cap-dipsticks. He asked the pilot for instructions and, although some advice was given, the pilot did not check the security of the dipsticks.

Take-off was commenced towards the north into a 10-15 knot wind with a surface temperature of about 20 degrees C. Shortly after lift-off, at the first power reduction, the observer in the co-pilot's seat advised that there was oil seeping back along the cowl from the right-side oil filler hatch. The pilot reported that he increased power to both engines but believed there was no response from the right. He began an immediate left turn to complete a circuit and attempted to secure the right engine and feather the propeller. The aircraft then began a roll to the right, the nose dropped, and the aircraft impacted the ground. As the aircraft rolled right and the nose dropped, the pilot reported that he had secured the left engine and feathered the propeller. The observer in the co-pilot seat reported hearing a continuous stall warning horn as the right wing began to drop.

All occupants, although injured, were able to vacate the aircraft through the main cabin door. The pilot provided assistance to the passengers and then returned to the airport to summon help.

Examination of the wreckage revealed that the aircraft impacted the ground in a nose down, right wing low attitude while turning right. The landing gear collapsed due to impact forces and the right wing separated. Deceleration and impact forces were severe. The right propeller was found in the fine pitch range with no damage to the uppermost blade and the other two bent backwards. The right engine oil filler cap-dipstick was found to be correctly installed in the oil filler neck. There was a pattern of engine oil over the rear of the engine and inside the cowl originating from the oil filler neck.

The left engine was partially torn from its mountings and displaced about 90 degrees to the right. Its propeller was in the fully feathered position. The oil filler cap-dipstick was on the ground adjacent to the engine. An oil spill pattern similar to that on the right engine was evident.

The pilot in command held a Senior Commercial Pilot Licence, a Command Instrument Rating, and a current Class 1 Medical certificate. He was endorsed on the aircraft type and had last been checked in emergency procedures eight months previously.

The person in the co-pilot's seat had recently qualified as a commercial pilot and had completed some flying training with the operator. He was on board the flight to observe a typical commercial operation to enhance his employment prospects as a pilot. This observer status had been previously granted to other pilots. The company management provided strict guidelines to pilots in command of such flights regarding the non-active role of these observer pilots.

The aircraft maintenance release was valid, and the aircraft had been loaded within the Flight Manual maximum weight and centre of gravity limits at the time of the accident.

The right engine was run on a test stand and assessed as being capable of normal operation. The combination oil cap-dipstick prevented oil loss when correctly inserted and clipped down. When in place but not clipped down, with the engine running above 1800 rpm, an oil leak pattern similar to that seen at the accident site occurred over the rear of the engine.

It is considered likely that the dipstick had been loose prior to impact but was correctly replaced in the filler neck after the accident. The design of the oil filler system tends to restrict oil loss with a loose dipstick. This condition would not require an immediate reaction by the pilot to prevent engine damage.

The right propeller was dismantled for inspection and found in the normal fine pitch range but capable of feathering. The uppermost blade was not damaged and backwards bending of the other two blades indicated that it was stationary or rotating slowly at impact.

Severe impact damage to the left engine precluded a test run. It was bulk stripped with no defects evident that would have prevented normal operation. The left propeller was dismantled and found to have been in the fully feathered position prior to impact. Damage sustained would indicate that it was stationary or rotating slowly at impact.

Based on the physical wreckage and impact examination and on the pilot and passenger comments, it is evident that when the pilot secured the right engine and began the left turn, the airspeed dropped, and the aircraft stalled. When the right wing dropped the aircraft entered an incipient spin. Due to the low altitude at which control was lost, the pilot was unable to effect a recovery.

Findings

1. The aircraft had a valid maintenance release and was within maximum weight and centre of gravity limitations at the time of the accident.
2. The pilot-in-command was correctly licensed and endorsed for the aircraft type.
3. Oil levels had been checked and oil added to the right engine by a non-crew member.
4. The combination oil cap-dipsticks had not been checked for correct installation by the pilot-in-command and were probably loose at take-off.
5. The oil filler design of the engine will restrict oil loss when a dipstick is not correctly secured.
6. The left propeller was feathered, and the right propeller was in the fine pitch range; both were stationary or rotating slowly at impact.
7. The right engine was capable of normal operation and was successfully run on a test stand after the accident.
8. Impact damage to the left engine precluded a test run but a strip inspection indicated that it was capable of normal operation.
9. The aircraft stalled and entered an incipient spin to the right prior to ground impact.

Significant Factors

1. The pilot-in-command reacted inappropriately to a perceived engine problem shortly after take-off.
2. Control of the aircraft was lost at a height insufficient to effect a recovery.