What does a flashing white light signal mean to an aircraft on the surface?

Answer

Return to the starting point on the airport. (Flashing white is not applicable to aircraft in flight.)

14 CFR § 91.125

Read the full regulation — 14 CFR § 91.125

Part 91
Section 91.125
§ 91.125 ATC light signals.

ATC light signals have the meaning shown in the following table:

Color and type of signal  | Meaning with respect to aircraft on the surface | Meaning with respect to aircraft in flight
--------------------------+-------------------------------------------------+--------------------------------------------------------------------
Steady green              | Cleared for takeoff                             | Cleared to land.
Flashing green            | Cleared to taxi                                 | Return for landing (to be followed by steady green at proper time).
Steady red                | Stop                                            | Give way to other aircraft and continue circling.
Flashing red              | Taxi clear of runway in use                     | Airport unsafe—do not land.
Flashing white            | Return to starting point on airport             | Not applicable.
Alternating red and green | Exercise extreme caution                        | Exercise extreme caution.

Test yourself on this and 500+ more

Squawk Box is a free aviation micro-learning app. Flip cards, build streaks, stay sharp.

Try Squawk Box