A two coffee read.
It has taken nearly 34 months to provide the ATSB report into:-
Collision with terrain following an engine power loss involving Cessna 172M, VH WTQ, 12 NM (22 km) north-west of Agnes Water, Queensland on 10 January 2017
It is a ‘long’ read and some of the details (below) are worthy of note. ATSB have made some serious efforts to establish why the engine failed when it did. That primary mystery remains unresolved, not from lack of effort on the ATSB part; I can’t think of much else they could have done. Even a simulation would not be able to duplicate the exact circumstances to determine if some weird ‘air-lock’ due to un-porting of a fuel feed had occurred would not provide definitive answers to the puzzle (IMO). So why the engine failed, when it did will remain unexplained. However, there are some salutary lessons to be learned from the detailed investigation.
There are some things which (again IMO) could have been done better by the operator. For example, the beach inspection protocols. Anyone who has flown ‘in-the-bush’ the real thing, knows how difficult it is to even spot (stationary) livestock on an ALA from much above 3/400 ft; below that objects become much clearer, so there is an identified ‘requirement’ to get ‘low and slow’. How low and how slow is difficult to define – in terms which could be realistically transposed into SOP.
ATSB. - The pilot of the accident flight reported that he normally conducted airborne inspections of Middle Island ALA at 150–200 ft. A review of the GPS data identified 19 previous inspections of Middle Island ALA, all of which were conducted by the pilot of the accident flight. The lowest altitudes recorded during these inspections were generally below 100 ft with a median value of about 60 ft (see Review of airborne inspections at Middle Island ALA ). Given the relatively constant descents and straight flight paths involved in these inspections, the GPS data was probably within the GPS manufacturer’s expected level of accuracy.
ATSB. - Overall, the ATSB concluded that the altitude at the time of the engine power loss was probably between 40 and 80 ft and therefore probably close to the GPS-based altitude of 60 ft.
ATSB. - The inspections were generally flown at 50–100 ft AMSL while flying at normal cruise speed towards an area of water at the end of the beach, with no planned consideration of what to do in the event of an emergency.
Valid points – there was a requirement for almost a 180˚ reversal around the headland to land into wind. Ref Fig 2. With 150 or 160 feet on the clock, would there have been a better outcome? With a little less speed and a handful of flap, could the outcome have been less damaging? I wonder, had there been a little less ‘thrill’ for passengers and a little more conservative thinking been applied, could the whole accident have been avoided. I don’t know; would I be flat chat, flapless, at 60 feet over a beach, with a reversal to follow – I don’t think so. This is the sort of ‘stuff’ that needs to written into an Ops Manual – company SOP. Murphey is everyman’s co-pilot and anything that can be done to keep his mucky paws out of the equation should be done.
![[Image: ao2017005_figure-2_final.png?width=582&h...3&mode=max]](https://www.atsb.gov.au/media/5776718/ao2017005_figure-2_final.png?width=582&height=323&mode=max)
Engine mystery.
The engine sustained a sudden and total power loss. The engine/propeller speed immediately reduced and then gradually decreased for the remainder of the flight (see Audio analysis of the engine/propeller speed).
ATSB - Despite a detailed inspection of the engine and related systems, the ATSB was unable to identify the reason for the loss of engine power.
ATSB - During the period immediately prior to the engine power loss, the indicated fuel quantity was about one quarter full on the left tank gauge and slightly above half full on the right tank gauge.
ATSB - Based on an hour meter reading documented in maintenance worksheets on 12 November 2015, the flight time documented on the maintenance releases underestimated the actual flight time by 62.2 hours (or about 40 per cent) during the period from the periodic inspection on 1 May 2015 to the next periodic inspection on 12 November 2015.
ATSB - There were multiple days on which flights were recorded on the aircraft’s GPS unit and/or the pilot of the accident flight had included flights in VH-WTQ in his logbook, but there was no certification on the maintenance release stating that a daily inspection or flights had been conducted (see Appendix A).
ATSB - Prior to the sudden engine power loss at 1037:34, the only anomaly in the engine/propeller sound during the flight occurred at 1036:13, when there was a momentary reduction of engine/propeller speed before it recovered to its normal setting. This occurred during a rapid though brief pitch-down manoeuvre. The brief reduction in power appeared to be consistent with what would expected with the normal operation of the carburettor in such a manoeuvre and would have had no long-term effect.
The Go-Pro puzzle.
ATSB - Given the high degree of potential importance as evidence, an extensive search of the accident site for the GoPro cameras was conducted by the ATSB, police and state emergency service volunteers. That search did not locate either of the missing cameras.
ATSB - The reason why there was no memory card in the black-handled GoPro camera could not be determined, and the yellow-handled camera was never located
All food for serious thought; not the slightest bit of comfort for those grieving or hurt, but that is not the ATSB’s role. Despite the delay in the report being released, it is not too shabby an effort to define what went wrong. The only criticism I would gently make is that there is no advice provided, to prevent a reoccurrence; or, guidelines for Chief pilot’s to work with to set some minimum guidelines for pilots who need to make low level strip inspections.
Anyway, FWIW that’s all I can glean from the ATSB report, which is almost, but not quite up to world standard.
Toot - toot.
It has taken nearly 34 months to provide the ATSB report into:-
Collision with terrain following an engine power loss involving Cessna 172M, VH WTQ, 12 NM (22 km) north-west of Agnes Water, Queensland on 10 January 2017
It is a ‘long’ read and some of the details (below) are worthy of note. ATSB have made some serious efforts to establish why the engine failed when it did. That primary mystery remains unresolved, not from lack of effort on the ATSB part; I can’t think of much else they could have done. Even a simulation would not be able to duplicate the exact circumstances to determine if some weird ‘air-lock’ due to un-porting of a fuel feed had occurred would not provide definitive answers to the puzzle (IMO). So why the engine failed, when it did will remain unexplained. However, there are some salutary lessons to be learned from the detailed investigation.
There are some things which (again IMO) could have been done better by the operator. For example, the beach inspection protocols. Anyone who has flown ‘in-the-bush’ the real thing, knows how difficult it is to even spot (stationary) livestock on an ALA from much above 3/400 ft; below that objects become much clearer, so there is an identified ‘requirement’ to get ‘low and slow’. How low and how slow is difficult to define – in terms which could be realistically transposed into SOP.
ATSB. - The pilot of the accident flight reported that he normally conducted airborne inspections of Middle Island ALA at 150–200 ft. A review of the GPS data identified 19 previous inspections of Middle Island ALA, all of which were conducted by the pilot of the accident flight. The lowest altitudes recorded during these inspections were generally below 100 ft with a median value of about 60 ft (see Review of airborne inspections at Middle Island ALA ). Given the relatively constant descents and straight flight paths involved in these inspections, the GPS data was probably within the GPS manufacturer’s expected level of accuracy.
ATSB. - Overall, the ATSB concluded that the altitude at the time of the engine power loss was probably between 40 and 80 ft and therefore probably close to the GPS-based altitude of 60 ft.
ATSB. - The inspections were generally flown at 50–100 ft AMSL while flying at normal cruise speed towards an area of water at the end of the beach, with no planned consideration of what to do in the event of an emergency.
Valid points – there was a requirement for almost a 180˚ reversal around the headland to land into wind. Ref Fig 2. With 150 or 160 feet on the clock, would there have been a better outcome? With a little less speed and a handful of flap, could the outcome have been less damaging? I wonder, had there been a little less ‘thrill’ for passengers and a little more conservative thinking been applied, could the whole accident have been avoided. I don’t know; would I be flat chat, flapless, at 60 feet over a beach, with a reversal to follow – I don’t think so. This is the sort of ‘stuff’ that needs to written into an Ops Manual – company SOP. Murphey is everyman’s co-pilot and anything that can be done to keep his mucky paws out of the equation should be done.
Engine mystery.
The engine sustained a sudden and total power loss. The engine/propeller speed immediately reduced and then gradually decreased for the remainder of the flight (see Audio analysis of the engine/propeller speed).
ATSB - Despite a detailed inspection of the engine and related systems, the ATSB was unable to identify the reason for the loss of engine power.
ATSB - During the period immediately prior to the engine power loss, the indicated fuel quantity was about one quarter full on the left tank gauge and slightly above half full on the right tank gauge.
ATSB - Based on an hour meter reading documented in maintenance worksheets on 12 November 2015, the flight time documented on the maintenance releases underestimated the actual flight time by 62.2 hours (or about 40 per cent) during the period from the periodic inspection on 1 May 2015 to the next periodic inspection on 12 November 2015.
ATSB - There were multiple days on which flights were recorded on the aircraft’s GPS unit and/or the pilot of the accident flight had included flights in VH-WTQ in his logbook, but there was no certification on the maintenance release stating that a daily inspection or flights had been conducted (see Appendix A).
ATSB - Prior to the sudden engine power loss at 1037:34, the only anomaly in the engine/propeller sound during the flight occurred at 1036:13, when there was a momentary reduction of engine/propeller speed before it recovered to its normal setting. This occurred during a rapid though brief pitch-down manoeuvre. The brief reduction in power appeared to be consistent with what would expected with the normal operation of the carburettor in such a manoeuvre and would have had no long-term effect.
The Go-Pro puzzle.
ATSB - Given the high degree of potential importance as evidence, an extensive search of the accident site for the GoPro cameras was conducted by the ATSB, police and state emergency service volunteers. That search did not locate either of the missing cameras.
ATSB - The reason why there was no memory card in the black-handled GoPro camera could not be determined, and the yellow-handled camera was never located
All food for serious thought; not the slightest bit of comfort for those grieving or hurt, but that is not the ATSB’s role. Despite the delay in the report being released, it is not too shabby an effort to define what went wrong. The only criticism I would gently make is that there is no advice provided, to prevent a reoccurrence; or, guidelines for Chief pilot’s to work with to set some minimum guidelines for pilots who need to make low level strip inspections.
Anyway, FWIW that’s all I can glean from the ATSB report, which is almost, but not quite up to world standard.
Toot - toot.