Altimeter Bugs

[The Governor]

All our flying is based on QNH only but the aircraft do not have a physical bug on the altimeter to indicate the surface for instrument approaches.

We operate a type with analogue instruments only with no GPWS fitted. We only have an AVAD system which pilots generally ignore as check height warnings occur often in the environment we operate in.

Is there legislation in place that requires altimeters to have a bug fitted in the situation described above ? I have tried and failed to find any reference to this.

Any help much appreciated.

[VinRouge]

What happens when the airfield elevation is >1000'?

Many modern aircraft have both rad alt bugs and settable minima, so why the need for an altimeter bug? If you stick to the levels published on a procedure, an altimeter bug is useless and arguably a distraction to other markers, such as Alt Set and procedure minima.

If your pilots ignore the calls, I would be heading down the route of training, rather than introducing new equipment, as amendments to company SOP will typically be cheaper and more effective. Put it this way, if pilots are not doing what they are supposed to be doing now, then what is to suggest they will even use a altimeter bug if it was fitted?

[Mach E Avelli]

Flight Safety Foundation recommend using all the tools at your disposal for altitude awareness. Unless flying an ILS, using the altsel for minima and setting the radalt (on non-cat 2/3 approaches) to some sensible height BELOW minima (to avoid early spurious warnings) are techniques adopted by many operators.
Then if the rad alt goes off or you go below the altsel 'below level' trigger (usually 100 to 150 ft) and you are not visual, a missed approach becomes mandatory. Sure, you will have busted minima, but better to go around late than not at all in such a situation.
What is most important is to avoid over-using the radalt or altsel or various bugs to gather useless information or to become pre-conditioned to ignoring warnings. One operator I did some training with had the ridiculous notion that the radalt should be set to 400ft for every takeoff. The idea was to take off with the amber warning light ON and when it went out that was the cue to accelerate. For a visual approach they set it to threshold elevation for reasons I never could grasp. Anti-logic.