Hi,

Could you please check the test exam (#2) q15? ("You have been cleared to fly the Canberra 35 ILS-Y approach in VH-OZY [...] Your maximum asymmetric missed approach gradient will be 2.5% under the ambient conditions...).

The explanation says: " However, in this case, the published visibility is higher than that. You would have to use 2km visibility for the minimum on this approach."
And then: The correct answer is: 1.6 km (which is according to the approach plate is for 3.3% gradient)

Thank you,
David

G'day,

according to the May 26th Plate, the 1.6km is the required vis for the 2.5% gradient and 1.6km is the correct answer. There was a misprint in the explanation where the old 2km was still listed.



Cheers,

Rich

Caveat - Wisdom dictates that one keeps the idealised exam stuff distinct from the real world version, noting that, for the exam, the idealised answer is required.

Light twins, at commercial weights in the real world, generally have little chance of achieving anything like 2.5% OEI .. in practice, IFR, either one operates at very light weights (not usually feasible), or redoes the sums to adopt a higher minimum for the miss to account for real world performance. He/she who simply goes to the published minimum blissfully expecting to be able to achieve the miss requirements .. is being very optimistic and, potentially, awaits a surprise sooner or later ... Places such as CBR and HBA, with their tiger country environments, are of particular concern for OEI escapes.

This is made worse by the different MTOW certification climb requirements for this class of aircraft .. the smaller light twins can be expected to have abysmal OEI performance. One recalls the old wisdom that the remaining engine simply takes one to the scene of the accident.

The real worry is that the average pilot has little knowledge of his/her light aircraft OEI performance and it is fortunate that we see very few real world OEI approach and landing requirements in anger.

Thank you Richard - of course I checked the 'old' approach plate... Sorry for the confusion.

Hi John,

thank you - I agree with the old wisdom: 'One recalls the old wisdom that the remaining engine simply takes one to the scene of the accident.'

Exactly what my instructor told me when we were practicing one engine approaches. It's always practical to use the actual figures for the aircraft I'm flying and to know the real figures.

Cheers,
David

No worries. Interesting to note the answer changes post-26th May... It is a never ending job trying to keep on top of these updates!