Collision with terrain

1. The aircraft stalled at an altitude from which a recovery was not effected.

Environment

The density altitude of 3,400 ft and the aircraft's gross weight (just below the maximum permitted) combined to adversely affect the aircraft's acceleration and climb performance. This was evident from the witness reports stating that the aircraft's angle of climb seemed to be shallower than normal for single-engine light aircraft departing on runway 30. The brief loss of altitude before the right wing dropped was probably the result of the pilot raising the flaps.

As the aircraft was lower than the normal climb profile, rising terrain ahead might have affected the pilot's assessment of the aircraft's nose attitude with respect to the horizon or its rate of climb with respect to terrain, leading him to select a higher nose attitude than he would have selected otherwise.

Pilot

Although precise figures for the pilot's total experience and his experience on type could not be determined, he was known to be relatively inexperienced. However, he had completed several previous flights in the Musketeer, including at least two flights with a passenger in a rear seat.

The four aircraft occupants had arrived back in Canberra at about 0130 on the day of the accident after driving in two vehicles from Brisbane. The pilot had risen by 0630. He could not have had more than 5 hours sleep in bed after arriving home. However, it cannot be assumed that he did all the driving; the other vehicle occupant might have driven the final trip from Umina to Canberra, permitting the pilot to obtain some sleep during that time.

Although it could not be confirmed that the Musketeer was the source of the open microphone transmissions on SMC frequency, some of the phraseology heard at the time supported this conclusion. In the event, the pilot might have had his confidence shaken, resulting in the errors in his readback of his take-off clearance.

After receiving the traffic information about the inbound helicopter directly ahead, the pilot may have been devoting considerable attention to looking for the helicopter, allowing his concentration on flying the aircraft to lapse.

The reason for the stall could not be established.

Stall warning system

Although it could not be confirmed, it is possible that the stall warning system did not operate, thus denying to the pilot the aural warning of an approaching stall.

The Beech Musketeer aircraft was being operated on a private pleasure flight. On board were the pilot and three passengers.

The aircraft took off from runway 30 and began climbing at a shallow angle, which a witness reported was below the normal climb profile. When the aircraft reached a point about 100 m beyond the upwind threshold of the runway, the tower controller informed the pilot of inbound traffic directly ahead of the aircraft. At that time, the tower controller also noticed that the aircraft was exhibiting `wobbles' and became concerned for its safety. Witnesses reported that the aircraft slowly climbed to about 300 ft and then seemed to lose altitude. The aircraft then continued tracking outbound in a shallow climb on runway heading, before the right wing dropped. The aircraft then rolled to the right, assumed a steep nose-down attitude and began rotating. After one turn, the aircraft impacted the ground in a steep nose-down inverted attitude. A fireball engulfed the aircraft immediately after impact. The four occupants received fatal injuries.

The accident site was located in an open paddock covered with dry grass, about 1.3 km from the upwind threshold of runway 30 and about 200 m left of the extended centreline. The wreckage was contained within an area about 30 m by 20 m, consistent with the nature of the impact. However, before being extinguished, the post-impact fire burned out an area about 130 m by 80 m.

The evidence indicated that the flight proceeded normally until the propeller failed. The pilot correctly diagnosed the nature of the problem and appeared to have been attempting an emergency landing when the accident occurred. It is possible that, with little effective power being available from the engine, the aircraft entered a low speed/high rate of descent situation during the final landing approach. Any yaw existing at the time could have been sufficient to cause the aircraft to roll left or right. The impact dynamics were consistent with such a sequence.

It is possible that vibration caused by the out-of-balance propeller limited the pilot's ability to accurately interpret the aircraft instruments, including the airspeed indicator. Such a situation might have affected his control of the airspeed during the final approach to the landing area and may have contributed to the loss of control.

The distortion to the cockpit sides was very similar to the damage sustained in a fatal accident involving an RV-3 aircraft on 12 March 2000 (ATSB Occurrence Brief 200000885). Both aircraft were originally designed under US Federal Aviation Regulation Part 121-191 (experimental - amateur). As such, they were not required to meet any design standard.

The degree to which the pilot's medical conditions may have affected the final outcome could not be established.

The investigation was unable to determine the factors leading to the accident, other than the failure of the propeller blade.

The owner/builder of the Vans RV-6A aircraft was conducting a flight from Townsville to Toowoomba. The aircraft departed Townsville at 0846 local time. The pilot subsequently contacted Oakey Approach at 1324, and the aircraft was identified on radar at 3500 feet. The pilot was instructed to maintain that altitude. When the aircraft was about 26 nautical miles from Toowoomba, the pilot transmitted a mayday distress message stating that the aircraft's engine had failed. A short time later he reported that a propeller blade had failed. No further transmissions were heard from the aircraft. About 30 minutes later, a searching helicopter located the wreckage in a flat clear area amongst hilly, tree covered terrain.

The reason for the loss of control of the aircraft could not be positively established. Pilot incapacitation leading to a loss of control was a likely factor.

Due to his medical condition, the pilot might have suffered a coughing fit in flight that impaired his ability to fly the aircraft. Alternatively, the concentration of doxylamine in his system might have led to drowsiness or even disorientation associated with aerobatic manoeuvres. Other possible reasons for a loss of control of the aircraft include pilot incapacitation for some other reason, and loss of consciousness, or partial loss of consciousness, due to the onset of g loadings when conducting an aerobatic manoeuvre.

Entries in the pilot's logbook indicated that in the past, the pilot had been prepared to abandon flights due to poor weather. This provided some support for the contention by those who knew the pilot that he was cautious with respect to weather. The weather forecasts obtained by the pilot did not indicate that conditions were unsuitable for the flight, and the decision to proceed at that stage was probably appropriate. However, the pilot had reported that the weather conditions while overhead Goondiwindi, approximately one hour before the accident, were not good. It should have become apparent to him as he continued towards the coast that the weather conditions were deteriorating to the point where they were unsuitable to continue the flight.

The investigation was not able to determine why the pilot made a decision to continue with the flight when confronted with weather conditions that were obviously worse than those forecast, and that appeared to be unsuitable for VFR flight.

The pilot's initial handling of the aircraft when in IMC appeared reasonable under the circumstances. The left turn to intercept the track from Toowoomba to Caloundra was performed with a degree of accuracy and was indicative that the pilot was probably using the GPS for navigation. The steady heading and slow but constant rate of descent which were evident after the aircraft was established on track to Caloundra suggested that the aircraft was probably being flown on autopilot.

The subsequent failure of the pilot to fly the assigned heading, the increased ground speed and rate of descent, and the consequent loss of control are consistent with the pilot becoming spatially disoriented during the right turn onto 130 degrees and having disconnected the autopilot. The aircraft impacted the ground in close proximity to the last radar-observed position, less than 90 seconds after the pilot's last radio transmission was received by ATS. Based on witness reports and evidence at the accident site, the aircraft was in a left spiral dive before impacting the ground.

The pilot of a VFR aircraft is solely responsible for ensuring that the flight is operated with due regard for changing weather conditions. In this particular instance, for reasons that were not established, the pilot placed himself in a situation where weather conditions were unsuitable for VFR flight; a situation for which he was not trained or qualified. Having placed himself in that situation, the ATS response became a matter of primary importance. ATS staff play a vital role in assisting pilots in an in-flight emergency situation. The timeliness and effectiveness of that assistance is particularly important when dealing with VFR pilots as they are subject to unique emergency situations and often have limited skills and experience. In addition, as VFR pilots generally operate as a single crew, they rely heavily on external assistance when faced with emergency situations such as inadvertent flight into IMC.

The ATS response to this in-flight emergency would have been enhanced through a greater understanding and application of the strategies and techniques suggested in the Manual of Air Traffic Services, the IFER training manual and the IFER checklist. Controller actions suggested that they did not have the background knowledge to effectively manage the in-flight emergency situation. In particular, the controllers did not appear to be aware of the potential consequences and therefore the priority that needed to be afforded to the pilot.

The strategy adopted by the controller in responding to the in-flight emergency situation was not consistent with the guidance provided in chapter 17 of the Manual of Air Traffic Services, the IFER training manual or the IFER checklist in use. In particular, the pilot was placed in a situation where he was turning and descending the aircraft at the same time. In addition, the pilot was also required to respond to questions from ATS while performing these manoeuvres. It was unlikely that the pilot had the skills or experience that were required to enable him to cope with these demands. Although the controller's communication style was in accordance with standard phraseology, the authoritative and interrogative style was inappropriate in the circumstances and was unlikely to have instilled confidence in or reassured the pilot.

Although the Manual of Air Traffic Services provided basic guidance on the strategy needed to deal with a VFR pilot operating in IMC and although the IFER checklist served as an aide-memoire, neither provided the level of detail contained in the IFER training manual. It is significant that this, or an ADF equivalent, manual was not available to ADF ATS units.

The circumstances of this accident are consistent with an uncontrolled collision with terrain following the pilot's loss of adequate external visual reference. It is likely that he became spatially disoriented and lost control of the aircraft soon after descending through 3,200 ft. The aircraft subsequently entered a left spiral dive before impacting the ground. As a result of concerns regarding military air traffic control officers' awareness of in-flight emergency response practices and procedures for civil aircraft, the Australian Transport Safety Bureau issued interim recommendation IR19990190 to the ADF on 16 December 1999.

The pilot of a Cessna 182J was conducting a private visual flight rules (VFR) flight, with one passenger, from Lightning Ridge to Caloundra. The passenger was also a qualified private pilot.

Prior to departure at about 0845 EST, the pilot obtained an Airservices Australia location briefing containing weather and notice to airmen (NOTAM) information relevant to the flight. At about 1000, the pilot used a mobile phone to contact an associate in Lightning Ridge. The pilot indicated that he was over Goondiwindi, tracking via Toowoomba for Caloundra, and that the weather was not good.

At approximately 1100, the Australian Defence Force (ADF) Amberley approach controller observed an unidentified code 1200 secondary surveillance radar (SSR) return in close proximity to the boundary of military airspace, about 10-12 NM north-east of Toowoomba. Code 1200 is allocated to VFR flights operating outside controlled airspace and not participating in a radar information service. The SSR return provided unverified mode "C" altitude information that indicated the aircraft was at 5,700 ft above mean sea level. The controller soon became concerned that the aircraft was going to enter controlled airspace, and that it might conflict with a General Dynamics F111 that was inbound to Amberley from the north with an in-flight emergency.

The controller attempted to contact the pilot of the unidentified aircraft by making a number of general broadcasts on the Amberley approach frequency. The controller also requested that the Airservices Australia Downs radar advisory service controller make a general broadcast for the pilot to contact Amberley approach, which he did at 1106:37. The Amberley approach controller informed the pilot at 1107:57 that his aircraft was identified on radar. At that time the aircraft was inside Amberley controlled airspace bearing 310 degrees M and 30 NM from Amberley. The pilot was immediately instructed to conduct a left orbit to provide separation with the F111.

During the orbit, the pilot advised the controller that the aircraft was "caught in cloud" and that he was "in trouble". A number of broadcasts between the controller and the pilot subsequently took place as the controller attempted to clarify the situation. During that time, the pilot asked whether he could use the automatic pilot. The quality of the radio transmissions from the aircraft was poor and the controller had difficulty in comprehending the full extent of the problem and the pilot's request to use the autopilot. The controller reported that these difficulties were exacerbated by the pilot's accent.

By the time the controller established that the pilot wanted to track to Caloundra and was rated only for VFR flight, but was in instrument meteorological conditions (IMC), the pilot had commenced a second left orbit. The aircraft was approximately half-way through the second orbit, passing a heading of approximately 240 degrees when the controller instructed the pilot to turn right and take up a northerly heading for Caloundra. While the aircraft was in the right turn, the controller asked the pilot if he wanted descent, to which the pilot replied in the affirmative. The controller then cleared the pilot to leave control area on descent.

Changes in the aircraft's altitude during the right turn were erratic. Radar recordings indicate that the aircraft descended to 4,400 ft in less than a minute, then climbed back to 4,800 ft. The pilot maintained the right turn onto a heading of about 130 degrees before making a left turn to intercept the track from Toowoomba to Caloundra. During that time, the controller advised the pilot that he could descend to 3,000 ft safely in the aircraft's current location. Once established on track to Caloundra, the aircraft maintained a steady heading, with a rate of descent of about 300 ft/min.

After the aircraft was established on track for Caloundra and was still in IMC, the controller became concerned that the aircraft was heading for an area of higher terrain, where the radar lowest safe altitude, as specified on the radar terrain clearance chart, was 3,800 ft. As a result, the controller instructed the pilot to turn right heading 130 degrees (a turn of about 90 degrees). The aircraft was passing 3,700 ft when the pilot commenced the right turn. Recorded radar data indicated that the aircraft continued the right turn through the assigned heading and that the aircraft ground speed and rate of descent increased during the turn.

The aircraft SSR return disappeared from the radar display at approximately 1116 as the aircraft was passing 3,200 ft on a heading of about 210 degrees. Controllers at Amberley reported that that was consistent with known radar coverage in the area. The pilot responded to a question from the controller regarding the aircraft's in-flight conditions at approximately 1116:00. Radio contact with the pilot was lost after that time. The Amberley approach supervisor subsequently contacted the emergency services number to find out if there had been any reports of accidents. The supervisor was switched through to Ipswich police, who advised that they had received a report of an accident in the Esk area.

The wreckage of the aircraft was located approximately 6.5 km north of Esk on flat pastoral land. A nearby resident caught a glimpse of the aircraft just before impact and then observed a plume of fuel and debris. He immediately notified emergency services, who recorded the call at 1117:30. Impact evidence indicated that the aircraft was in a left turn in a nose-low attitude and that the aircraft was not in a stalled condition. This is consistent with witness reports that indicate the aircraft was descending in a left turn. The impact destroyed the aircraft and both occupants were fatally injured.

Pilot in command

The pilot held a private licence, together with a valid class two medical certificate, and was appropriately endorsed. However, he did not hold a rating for flight in IMC, nor was the aircraft approved for flight in IMC. The pilot had logged a total flight time of 220 hours, comprising 90 hours dual and 130 hours as pilot in command by day. No evidence was found that the pilot was suffering from any medical condition that could have contributed to the accident.

The pilot was reported as being cautious and conscientious in his approach to flight preparation and in-flight procedures. In particular, flying instructors who had flown with the pilot reported that he was wary of flying in poor weather. The pilot's logbook indicated that on at least three previous unrelated occasions, the pilot had abandoned flights and returned to Lightning Ridge due to adverse weather. An associate of the pilot reported that he spoke to him prior to his departure on the day of the accident and that the pilot had expressed reservations about making the flight to Caloundra. He had stated that he intended assessing the weather at Goondiwindi before proceeding further.

Aircraft information

A periodic maintenance inspection was due approximately 10 hours after the commencement of the accident flight and there were no known outstanding maintenance defects. Evidence indicated that the engine was operating at impact and examination of the wreckage did not reveal any deficiencies that were likely to have contributed to the accident. The aircraft was fitted with an emergency locator transmitter (ELT), which was destroyed on impact. A global positioning system (GPS) unit was fitted to the aircraft and the pilot was also carrying a hand-held unit.

Meteorological information

On the morning of the flight, the pilot obtained area forecasts (ARFORs) 22, 40 and 41, which covered his route. He also received terminal area forecasts (TAFs) for relevant en-route airfields and for Maroochydore and Archerfield, but there was no evidence that he received a TAF for Caloundra. ARFOR 40 covers a large part of south-east Queensland, including the eastern Darling Downs and the Amberley area.

The Area 40 forecast was valid from 0717 to 2100 EST. The forecast overview indicated cloudy conditions with rain areas and isolated thunderstorms, clearing from the west after 1800. Forecast cloud consisted of isolated cumulo-nimbus with a base of 6,000 ft and scattered stratus between 1,200 ft and 6,000 ft in rain, broken near thunderstorms. Also forecast was scattered cumulus and strato-cumulus with a base of 3,000 ft between the coast and the ranges and 4,500 ft inland, with broken alto-cumulus and alto-stratus layers above 16,000 ft. The predicted visibility was 5,000 m in rain and smoke and 2,000 m in the vicinity of thunderstorms.

The TAFs for Archerfield and Maroochydore were current from 0600 to 1800 EST. They predicted visibility in excess of 10 km, light rain and scattered cloud at 2,500 ft, and also forecast intermittent periods of reduced visibility down to 4,000 m, rain and broken cloud at 1,000 ft.

The pilot of the F111 reported that the area was dominated by large cumulus cloud with associated stratus. He reported that there were occasional gaps between the cumulus and stratus cloud levels, which resulted in small pockets of airspace where visual flight was possible. However, these pockets were only present above 5,000ft and were totally surrounded by cumulus and stratus cloud. The crew of the F111 reported that the cloud during their approach to Amberley, approximately 30 NM to the south-east of the accident site, was consistent broken low cumulus and stratus with a base of 650 ft above mean sea level.

A Bureau of Meteorology observer at Amberley stated that on the day of the accident, the weather was influenced by an easterly moving trough lying north-south through central Queensland and a north-easterly breeze off the ocean. The observer stated that these two influences were known to produce a build-up of low cloud against the ranges. Witnesses on the ground in the vicinity of the accident site described the weather as showery, with cloud covering the tops of the hills.

Air traffic services inflight emergency response

Air traffic services (ATS) emergency procedures were outlined in chapter 17 of the Manual of Air Traffic Services, a joint military/civil document. Section 3 of chapter 17 provided guidance on emergency phase declaration. Paragraph 1 stated that "[t]he appropriate emergency phase shall be declared to show the degree of apprehension felt for the safety of an aircraft and an indication of the scope of the SAR [search and rescue] action to be provided." Paragraph 6 stated that "[a]n Alert Phase exists when there is apprehension as to the safety of an aircraft and its occupants", and specifically noted that an Alert Phase existed when a flight restricted to visual meteorological conditions (VMC) was operating in IMC.

Section 4 of chapter 17 referred specifically to procedures for the handling of in-flight emergencies by ATS staff. Paragraph 1 of section 4 stated:

"While it is impracticable to set out a detailed response to every emergency situation, it is possible to identify broad groups of incident types and to generalise appropriate courses of action".

Paragraph 2 stated:

"In resolving inflight emergencies, units should use the Inflight Emergency Response Checklists as a basis for the provision of assistance to pilots".

Information and guidance specific to "Flight confined to VMC but operating in IMC" was contained in paragraphs 48 to 53 of section 4. Paragraph 48 highlighted the fact that "[t]his type of inflight emergency is potentially a very serious situation which has often led to fatal consequences".

The section also provided general guidance to ATS staff on issues about which they needed to be aware, and strategies to be employed in responding to this type of in-flight emergency. In particular, it stated that ATS staff should be aware that a pilot in this situation would have difficulty with the following:

1. maintaining headings;
2. maintaining altitude; and
3. perceiving aircraft attitude.

Furthermore, the section stated that ATS should endeavour to provide reassurance to the pilot in the initial communications and limit communication so as not to divert the pilot's attention from flying the aircraft.

More detailed guidance on handling in-flight emergency response situations was provided in Airservices Australia's Inflight Emergency Response (IFER) Training Manual. The IFER training manual expands on specific issues listed in the Inflight Emergency Response Checklists.

The ATS strategy for an aircraft in a "VFR in IMC" situation was detailed in the IFER training manual and stated that it "should reflect the absolute pilot priority to control the aircraft ahead of navigation or communications". The following advice to assist pilots in such a situation was provided in the training manual:

"

1. Provide the pilot with some reminders on aircraft handling. While [the controller] is not expected to "fly" the aircraft for the pilot, the following handling actions are universally recognised as appropriate basic advice to an inexperienced pilot in distress:

   1. concentrate on aircraft attitude ie.:

      - maintain steady heading;
      - keep wings level;
      - keep speed constant

   2. trust instrumentation;

   3. when manoeuvring commences:

      - no abrupt manoeuvres;
      - shallow/climbs/descents/turns;
      - turns first, establish straight and level then climb/descend,

2. Provide navigation information to the pilot that will allow the aircraft to be re-established in VMC.
3. Communicate with the pilot using the following techniques:
   1. keep instructions simple and distractions to a minimum;
   2. keep regular radio contact without overloading;
   3. instil confidence and reassure the pilot; and
   4. pass only one item at a time

The IFER training manual also provided guidance on the communications style which should be adopted by controllers when dealing with this type of emergency. Specifically, the manual noted that a VFR pilot in an IMC situation is under considerable stress and there was a need for ATS staff to convey empathy, patience and confidence. This required ATS staff to adopt a markedly different technique to the customary delivery of ATS information, where precision and economy of words are appropriate to communications between confident professionals. Furthermore, in establishing the necessary background information, it was vital that questions not be put in an interrogative manner.

The IFER checklists, a document separate from the IFER training manual, contained items that should be considered when responding to specific situations. However, checklists serve primarily as an aide-memoire. A high level of background knowledge and situational awareness by the controller is required to expeditiously provide assistance to the pilot. In this regard, while the checklists are a useful tool, they need to be considered in conjunction with more detailed guidance, such as that contained in the IFER training manual.

A review of the audio voice recording revealed that the controller's manner while communicating with the pilot was authoritative, with questions being posed in an interrogative style. The controller used the IFER checklist during communications with the pilot. However, the unit was unaware of the existence of the IFER training manual.

The register of copy holders in the front of the IFER training manual indicated that ADF was a registered holder of three copies. However, the ADF was unable to locate these copies and the manual was not held by any ADF ATS unit. Airservices Australia records did not provide any receipt confirmation advice relating to the document copy numbers listed against the ADF.