I've just finished reading the report and I'm a bit dumbfounded. I regularly either write or supervise engineering reports for both clients and as court reports. Overall, I think the ATSB document fails as an engineering report and I would question whether the author has sufficient technical understanding for the job. I find it interesting that it has a range of human factors texts cited in full Harvard referencing discipline. However there is no reference to technical and measurement equipment used, its calibration, not a discussion on the limits of accuracy.
This is not a technical document.. It fails any basic test as an engineering report.
Furthermore, the references to surging RPM and engine roughness through "uneven fuel distribution"are prima facie contradictory. I am concerned that the author does not understand the operation of a CSU. If the statement that the RH engine was exceeding the maximum permissible RPM is correct, then this points to a CSU issue, not an engine issue. The engine should not be able to make the propeller go faster than redline. This also fits the history of that aeroplane (which is glossed over by the ATSB). I might come back and side with John Deakins a little, because if an engine monitor showed normal EGT's it would have allowed the pilot to immediately deduct a propeller issue. Although the standard equipment TIT should be adequate for this. A single non firing cylinder should cause an overall drop in TIT.
The reports inclusion of un-named pilots opinion of the PGW pilots flying ability makes me as mad as hell. This is nothing better than reporting on gossip and has no place in a professional report. If the ATSB saw value in collecting opinions of the pilots ability beyond that of those tasked with doing so by the CASA regulations (ie Chief Pilot, ATO, etc) then the correct way is to conduct structured interviews, disclose the position of the interviewees, append the list of questions and cite quotations from individuals and / or conclusions while keeping the identity of those question confidential. This is easy, routine and practiced by the market research industry daily. Frankly, it makes the ATSB look like hack amateurs in my opinion.
In my opinion, the report also seems to indulge in gratuitous criticism of the operator and its operating discipline that is not germane to the accident. If this is an accident investigation, lets stick to the accident. If its a witch hunt, then lets call it that.
Here is my hypothesis & take home lessons.
1. It looks like PGW lost a lot of height before the engine was feathered and the pilot was trying to diagnose the issue. I'm not sure that I've really seen this discussed, but it sounds real. Its possibly a reminder that in some situations you might be better to go straight to feathering an engine rather than diagnose it.
2. The pilot did not immediately go to VYSE and I think this might be a reminder that regardless of altitude or descent profile, that this is the best practice.
3. It looks like the pilot has tried to fly a normal descent profile back to Bankstown. I can absolutely see how one could be suckered into this. In part its an attempt to manage stress and make things closer to normal and potentially a fear of arriving too high. There is a joke about forced landings in Pitts that you choose the landing spot by throwing a brick out and following it down. I think this is a reminder that you need to plan to be way high. Its better to land at an airport fast & high and run off, than not land at an airport.
4. The pilot tried to follow the directions of ATC. Once we have a problem, the pilot should be assertive in telling ATC what he needs. I'm disappointed there is no discussion in the report of whether ATC might not have played a more supportive role. The stuff about not making a PAN call is bureaucratic mis-direction. The controller knew it was an emergency. Some of the US radio transcripts of emergencies we read in magazines show the controllers taking an active role in coaching or supporting the pilots. Should we encourage that here? Would the outcome have been different if PGW had not been directed to descend from 5,000ft to 2,500ft, but instead have been allowed to continue at the pilots discretion?
5. Trying partial power asymmetric is not something I have experienced in my training. "Fire, Fix or Feather" is drummed into us. Is there a role for trying a partial power setting first?
6. There but for the grace of god.... I'm not sure how well I'd stand up to the personal scrutiny that the ATSB gives pilots. I'd like to think I wouldn't make the same errors as this guy. But he seemed a pretty good diligent pilot and in quiet moments, I'm not really sure how much better I might have done. Which is why we deserve decent ATSB reports.