We asked on Thursday, just what was the significance of a rotating amber beacon, and we got a lot of different answers.

The replies fell roughly into four categories:

1) seaplane base
2) heliport
3) guess/other
4) unusual traffic pattern

Starting from the top, some answers got really close; except that we asked about an amber beacon, not yellow, or yellow-white alternating.

1) Seaplane base?

• For seaports, not often seen except in Alaska. (A.B.)
• The amber beacon signifies that there is a water runway. (Dave)
• Seaplane? (Ed)
• Marine Air Terminal? (David) [Hey--cut him some slack; he's from Colorado -- how would he know about a marine terminal?]
• My guess is a water airport for sea, float or amphibians. (Mark)
• That would be a seaplane base. (Bob)
• An Amber Beacon signifies a seaplane base. Last I heard, the Amber Beacon still operates at Dade County's "Government Cut," the longest runway in the world. Chalk's Airline operated(s) a variety of seaplanes on scheduled air service since 1926 from this runway. Today, Cruise ships plough Government Cut, giving seaplanes the "opportunity" to occasionally go around. Government Cut parallels the MacArthur Causeway in Miami. (Steve)
• I believe it is used for night landings at a seaport in the same manner that a flashing white/green beacon is used for a land airports. (Larry)
• Sea plane landing areas. (Tom)
• I think it was for seaplanes. (Robert)
• Ken cited a high authority:
  It indicates a lighted water airport. From the AIM:
  2-1-8. Airport/Heliport Beacons (snip)
  b. The colors and color combinations of beacons are:
  1. White and Green- Lighted land airport.
  2. *Green alone- Lighted land airport.
  3. White and Yellow- Lighted water airport.
  4. *Yellow alone- Lighted water airport.
  5. Green, Yellow, and White- Lighted heliport.
  NOTE-
  *Green alone or yellow alone is used only in connection with a white-and-green or white-and-yellow beacon display, respectively.
• ...and Bert explained the confusion: "Seaplane beacon. Yellow, followed by white." [The question wasn't really about "yellow/white," eh?]

2) Helipad/Heliport?

• The amber rotating beacon marks a heliport. (John)
• Helicopter pad? (Doug)
• I thought the amber rotating beacon was for "Air Ambulance Heliport" i.e. Hospital heliport. (Mel)
• Helicopter Landing Pad (LST)
• Amber with white and green means it's a heliport. Amber by itself means the edge of a (military?) drop zone. Good question. (Juan)
• A rotating amber beacon signifies a Seaplane Base... now if it is a white, green and amber beacon, then it's a heliport. (Steve)

3) Plausible Guesswork

• Airship Operations were indicated by an Amber Beacon. (Mike)
• For IMC approaches? Is this the equipment known for the famous death spiral? (Bob)
• Caution. Is that a vague enough answer so that someone who really doesn't know may still get it right? (Robin) [No, Robin, it's not --ed.]
• Tow truck. (Tim)
• Tacquitos are ready at the gee dunk. (That's 'breakfast tacos at the line shack snack bar,' for some of you.) (Mark)
• I believe the orange beacon is used for "alert situations" like an impending storm or high wind situations. (Heinz)
• Would rotating amber indicate freight only, no passengers? (Lady MAB)
• Actually there are two: (a) Personnel so designated by the airport manager to perform airport inspections were required to be in vehicles designated for inspections and equipped with a portable UNICOM and flashing amber beacon.,
  and (b) It used to be that if the amber light came from the aircraft it indicated that the aircraft has reached a point 6 miles from touchdown or the end of the runway, and clearance is requested to 3 miles. (Ron)
• 1st most common case: A ground inspection vehicle would have an amber beacon on it. (Paul)
• GARBO (green, AMBER, red, blue, and other color) beacons were the colors for the Low Frequency Airways (I believe from the 1920s-1950s). Currently  -- I Think -- yellow alone is for a lighted water airport, but is  used only in connection with a white-and-yellow beacon display. Probably wrong...usually am! [Mark, you're not wrong about the yellow light... but this was an amber question --ed.]
• Return to the point of departure (ramp). (John)
• How about an old airways beacon? (Kevin)
• Robert tried and tried, and finally gave up:
  The airport is under quarantine, no landings aloud.
  The Air Traffic Controllers got scared and left the building, land at your own risk.
  We don't want no stinking aircraft here!
  Mayor Dailey's back porch light. Ok... Ok, I don't have a clue.

4) Unusual Traffic Pattern

• Right traffic in use at the airport. (Paul)
• The Amber rotation beacon at an airport means Nonstandard Traffic Pattern, i.e., Right Hand. A prominent airport that had this was Meigs Field in Chicago, an airport I will dearly miss, (although a couple of my worst landings were there). (David)
• The amber beacon meant RIGHT HAND traffic. (Tom)
• I learned to fly in 1964 in a Cub, we flew into HAR (now CXY) using light signals occasionally. The flashing amber light, for RH traffic on 08 was mounted on the corner of the main hangar. (Ron)

To Paul, David, Tom, and Ron (and a few others who took more than one guess), congratulations; you know what to do when you see a rotating amber beacon! The bad news is, the amber beacons aren't used any more in the USA...

[Again, thanks to Gregor Saveskie, for the brain-teaser! --ed.]

FMI: www.faa.gov