[Peetwo]

AO-2017-118 : Cover-up or cock-up? - Part II

Interesting OBS "K", after some scrounging around some of the usual cyber-dustbins, I am now leaning towards a cover-up of the cock-up...

Note the following extract from the prelim report -   

The ATSB will continue to consult the engine and airframe type certificate holders, and utilise the expertise of the Seaplane Pilots Association of Australia. Accredited representatives from the Transportation Safety Board (TSB) of Canada and the United States National Transportation Safety Board (NTSB) have been appointed to participate in the investigation. A representative from the United Kingdom (UK) Air Accident Investigation Branch (AAIB) has been appointed as an expert to the investigation team under the same provisions. The AAIB will provide liaison with the passenger’s next-of-kin, citizen’s in the UK.

Given the accident pilot's dual citizenship with Canada, the TSBC reference in particular got me thinking - 

1st reference TSBC AAI report A00C0059 

The following part very much supports the "K" opinion:

Toxicological tests did not reveal the presence of alcohol or any other intoxicating drugs in the blood of the captain or the first officer. However, the levels of carbon monoxide in the blood of both crew members were elevated. The captain's carboxyhaemoglobin level was 17.9 per cent, and the first officer's level was 8.7 per cent. It was learned that the captain smoked more than one package of cigarettes per day and that the first officer was a non-smoker. Cigarette smokers may routinely have saturation levels of 6 to 8 per cent, and the effects of carbon monoxide are cumulative. Tolerance to carbon monoxide is not increased by smoking.

Many different classifications of severity of carbon monoxide poisoning are documented, indicating that the severity of symptoms does not correlate well with carboxyhaemoglobin levels. Generally, saturation levels of less than 5 per cent are not considered to cause any obvious symptoms. At saturation levels less than 25 per cent, physiological functions and the performance of skilled physical tasks are rarely affected. However, complex psychological functions involving judgement, situational decisions, and responses would be affected by levels between 5 and 20 per cent.Footnote3 Some classifications indicate decreased visual acuity at saturation levels of 10 to 20 per cent.Footnote4 Once the victim of carbon monoxide poisoning is removed from the carbon monoxide source, the levels decline. Information indicates that the half-life of carboxyhaemoglobin is about five hours. Altitude affects the saturation level because the partial pressure of oxygen decreases with altitude. Information concerning the altitude of the flights was not available.

The next reference provides a 'passing strange' coincidence in timing with the ATSB's belated, nearly 2 year request for toxicology review of the accident victims blood samples held by the NSW Coroner's office - https://www.tc.gc.ca/en/services/aviatio...019-07.pdf - note the release date was 12 December 2019...

CO has no color or odor. The onset of CO poisoning
can be insidious: victims are often unaware that their
environment is contaminated by this poisonous gas
and that their mental and physical functions are
being degraded. For these reasons, a CO warning
device is a very sensible investment for owners and
operators of GA aircraft. A suitable CO detector will
provide reliable, early warning of elevated levels of
this poisonous gas, allowing the pilot to take
appropriate actions. A CO detector can also
enhance the effectiveness of aircraft maintenance
actions. An inspection of the aircraft cabin with a
detector can confirm that maintenance or repair of
the exhaust or heating systems has corrected and/or
not introduced damage that could be associated with
the CO leaks. The type of functional check enabled
by a CO detector is not otherwise possible.

TC has concluded that preventive actions in addition
to those required by AD CF-90-03R2 may be
beneficial for owners and operators of GA aircraft in
Canada. These additional preventive actions are
described in the following section of this CASA.

So my question is that given the timing of the above Transport Canada CASA and the association of the TSBC with the active investigation, did the powers that be have an 'OH DUCK' moment when they discovered that toxicology reports weren't mandatory done in order to discount possible means of pilot and/or front RHS pax incapacitation?

MTF...P2