interior airspeed bug

[ZhagDrahr]

Interior airspeed bug: required (?) for (?) regulation reference (?) [USA]

[dv8]

Interior, could be internal i.e mechanical bug as opposed to external (manual) plastic bugs.

Perhaps or have I gone tits up

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dv8

[Capt Claret]

Zed Dee, on both the DH8 & 146 the interior bug is the reference speed for the fast/slow indicator on the ADI/PFD.

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bottums up !

[ZhagDrahr]

For clarification: Yes, an "internal" mechanically operated airspeed bug, usually used for V2, or Vref, as compared to a plastic bug on the outer rim of the airspeed indicator.

Again, is an internal bug required (for transport category FAA Part 121; and reference if so?

Thanks,
Zhag

[411A]

Zhag--
It would be required if the aircraft was originally certificated with one. Check the type certificate data sheet.
Older aircraft generally do not have one, newer aircraft do.