[Peetwo]

VH-UDB preliminary report released.

Via ATSB website:

Preliminary report

Published: 19 December 2017

On 24 October 2017, the ATSB was advised that wreckage of an aircraft had been located 30 km north-west of Albany Airport, Western Australia. A search had been mounted following a call to emergency services to advise that an aircraft had been seen in a steep descent before it disappeared from sight. Soon afterwards, smoke was observed in the direction of where the aircraft was last seen.

The aircraft was identified as a Cessna 210B, registered VH-DBU, which was being operated by the owner-pilot on a private flight from Albany to Bunbury. The pilot, who was the sole occupant, was fatally injured.

Figure 1: Nominal intended flight path

Source: Google Earth

The ATSB commenced an investigation and deployed investigators to the accident site. Other than recordings of radio transmissions made in the Albany area, there was no additional recorded data available to provide information about the flight. As a result, the ATSB was reliant on the radio transmissions, witness information and aircraft wreckage to establish the sequence of events.

At Albany Airport, the pilot made routine transmissions to check his radio and on entering the runway to position for take-off. Then, at 1033 (Australian Western Standard Time – AWST), the pilot transmitted that he was airborne from runway 14, maintaining runway heading (to the south-east), intending to make a right turn at 1,500 (ft above mean seal level (AMSL)) to track to Bunbury and climb to 6,500 (AMSL). This was the last recorded radio transmission from the pilot.

People who observed the aircraft start, taxi, and take-off did not notice anything abnormal about the aircraft. From aerial photos of coastal scenery around Albany that the pilot sent to an acquaintance and a report from an Albany resident, it appears that the pilot undertook some local flying before departing the area. There were a few people between Albany and the accident site area that heard an aircraft that could have been VH-DBU, but there was insufficient information to establish the aircraft flight path.

The key witnesses were located between 3 km and 5 km from the accident site in the general direction of Albany. Some witnesses related that prior to any apparent problem with the aircraft, the noise from the aircraft was loud and the aircraft seemed to be lower than was usual (for aircraft operating in that area). For a couple of witnesses, the noise was indicative of an aircraft manoeuvring. In regard to weather, the witnesses reported some cloud but generally clear and calm conditions.

The first sign of a problem was a loud and distinctive noise that witnesses described as a sharp bang, crack of a whip, gunshot, and thunder/lightning. This was an alarming noise that some witnesses associated with the aircraft that had just been heard or seen and prompted them to try and identify it.

Only one of the witnesses, located about 4 km from the accident site, saw the aircraft following the sharp noise. That witness recalled the aircraft was in a nose-down vertical descent rotating to the right and the engine noise was rising and falling. The witness watched the aircraft until it disappeared from sight due terrain and trees. Nothing was seen by the witness to separate from the aircraft and no smoke or vapour was observed coming from the aircraft.

Other witnesses related that, following the initial sharp noise, there were a series of sounds over an extended period (about 10 to 15 seconds according to one witness) that were described as similar to angle grinding or crashing through trees. Other descriptions were chopping, whirring, striking, whining, and high-pitched. One of the witnesses also recalled the engine revving during this time. These irregular noises stopped suddenly, probably upon impact with the terrain.

Figure 2: Accident site location

Source: Google Earth

The aircraft wreckage was located in heavy/dense bushland within the Mount Lindesay National Park. ATSB investigators gained access to the accident site and located wreckage with the assistance of Western Australia Police and the Parks and Wildlife Service.

From the examination of the aircraft wreckage at the accident site, the ATSB makes the following observations:

• the left wing (Figure 3), right wing, tailplane, and fuselage were not co-located, which is indicative of an in-flight break-up
  
• most but not all of the aircraft parts have been identified and these were found within an area of about 700 m long and 250 m wide
  
• the items furthest from the fuselage (main wreckage) were pieces of right wing skin and rear fuselage skin
  
• the main wreckage, that included the engine and propeller, was severely affected by fire
  
• many of the major parts of the aircraft had been damaged in-flight and during the ground impact
  
• the right wing outboard of the fuel tank had fragmented in-flight (Figure 4).
  

Figure 3: Left wing in as found position

Source: ATSB

Figure 4: Right wing inboard section in as found position

Source: ATSB

The ATSB recovered the wing, tailplane, and selected fuselage pieces to a secure storage location. A subsequent search of the accident site by State Emergency Service personnel located some more pieces of wreckage that were recovered to storage.

The ATSB conducted a further examination of the wreckage pieces and documented the damage for analysis of the break-up sequence and pre-accident airworthiness of the aircraft. No material defects have been identified nor is there direct evidence of an initiating event or action.

The pilot was qualified to conduct the flight and a maintenance release was issued in May 2017 to certify the aircraft as airworthy. At this time, a licenced aircraft maintenance engineer certified for a periodic inspection and compliance with a number of Supplemental Inspection Documents (SIDs). No significant defects were recorded.

The investigation is continuing and will include the following activities:

• Further analysis of the wreckage characteristics
  
• Consultation with the aircraft manufacturer
  
• Review of the aircraft maintenance history
  
• Review of the pilot records
  
• Analysis of meteorological data.
  

The Civil Aviation Safety Authority (CASA) is participating in the review of the aircraft wreckage and maintenance records to assess the implications (if any) of this occurrence for the continuing airworthiness status of the aircraft type and ageing aircraft in general. If there are any serious implications, the ATSB will communicate these as soon as practicable.

On 7 December 2017, the ATSB released a preliminary investigation report into the in-flight breakup of a Cessna 210 22 km east of Darwin Airport, Northern Territory on 23 October 2017, the day before this accident.

The ATSB acknowledges the support of Western Australia Police in Albany, Parks and Wildlife Service (Department of Biodiversity, Conservation and Attractions) personnel in Albany/Walpole, and State Emergency Service personnel in Albany/Denmark

     
MTF...P2