🔍 Key Concepts
• Light characteristics in the Light List (e.g., Fl, Qk Fl, frequency and period)
• How mile markers (AHP – Above Head of Passes) help you locate the correct aid to navigation
• Difference between single-flash, group-flash, and quick flashing lights
💭 Think About
• Look up Black Hawk Light at mile 318.3 AHP in the appropriate Light List or river chart and identify its listed characteristic: is it a single flash, a group of flashes, or continuous quick flashing?
• Compare the total period (in seconds) and the number of flashes in that period with each answer choice to see which one matches the published characteristic.
• Think about how group-flashing (e.g., two flashes) is written in light notation and how that would translate to “every X seconds.”
✅ Before You Answer
• Verify the exact light characteristic notation for Black Hawk Light (for example, Fl 4s, Fl(2) 4s, Fl(2) 5s, or QkFl).
• Confirm the total cycle time (the full sequence, including light and dark intervals) and match it to 4 seconds, 5 seconds, or quick-flashing (usually much faster than 1 flash per second).
• Make sure you are looking at the correct river mile and name (Black Hawk Light, mile 318.3 AHP) so you don’t mix it up with a nearby aid.