Originally Posted by
Lookleft
Where was the truck?
My issue is that the report can't get the facts right. It said the max height of vehicles is 4.6m and referenced a Vicroads document on recommended road clearances, not a vehicle requirement document.
The emphasis is on
recommended. There are plenty of bridges and other obstructions below this.
ADR 43/04 specifies vehicle dimensions. The max height is 4.3m.
State authorities allow exemptions under some circumstances. These will require an approval beyond homologation. In Victoria the common exemption is 2 level cattle trucks that will be permitted up to 4.6 m. But these are only allowed on declared roads and may include other restrictions. Other states have other exemptions. WA has numerous ones to cater for mining vehicles.
My favorite exemption is for Bushmaster vehicles that exceed the maximum single axle load limit. They need individual exemption each and every time they are driven on public roads that is valid only for the specified route and time.
The salient point is that:
a) The ATSB incorrectly refers to a non controlled vicroads advisory document as a defining document. The correct reference is ADR 43/04. Its not hard to get right.
b) the ATSB incorrectly list the maximum vehicle height as 4.6m. There is no requirement to provide 4.6m clearance.
Its a recommendation. There would be a bridge reconstruction project that would rival the level crossing project if it was a requirement.
c) The ATSB has criticized the pilot for being too low (which he was by admission) but failed to note that at the point of impact the aircraft was only 260mm below a 3 deg approach angle.
d) The ATSB did not consider if the Chieftan was on a 3 deg approach if it would have still hit the vehicle.
e) The ATSB did not comment on whether the driver had any degree of responsibility in having enough situational awareness to see an aircraft on his right hand side approaching at basically the same height.
f) The ATSB did not comment on the lack of warning road signs and whether or not this may be a useful risk mitigation strategy.
I agree that some of the pilots explanation is flaky. But notice they are not quotes, but the ATSB's summary points. The pilots comments may have been taken out of context or paraphrased by the ATSB. If the ATSB can change transcripts of recorded radio transmissions, then they can misrepresent a pilots interview responses.
I also agree that an approach that low is not good practice. But we're not all perfect and there should be some tolerance for deviation.