Scan Polishing

Joseph E. (Jeb) Burnside

Friday, January 21, 2022 at 11:46 AM ET

Verified

Key Takeaways:

View-limiting devices can make instrument flying more challenging than actual IMC by providing distracting peripheral vision and hindering internal instrument cross-checks.
Rigid adherence to commonly taught personal minimums can be overly restrictive, as practical experience and proper preparation may allow for safe operations in conditions often considered prohibitive.
The "dive and drive" approach procedure is largely outdated in modern aviation, with new technologies providing vertical guidance, and its use in general aviation carries significant risks, despite regulatory allowances for descending below MDA.

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I read your article, “Polishing Your Scan: Our Top Five Tips” (December 2021), twice. As always, it was well-written and thoughtful. I have to say my experience with view-limiting devices seems to be the opposite of that suggested in the article. Compared to flying with a view-limiting device, I find it easier to maintain precise parameters when I’m actually in solid IFR or in a simulator/AATD with zero outside visibility. In solid weather, all of a pilot’s attention is on the instruments.

I’m a CFI-I and I’ve noticed that my instrument students also maintain better parameters in the zero-zero world of the AATD compared to flight with a view limiting device. Secondly, I find that the outside peripheral vision available with a view-limiting device is often a negative. It can be a distraction that degrades the instrument crosscheck somewhat similar to flying under a cloud deck with ragged bottoms.