FAA Part 107 Remote Pilot (UAG)Airspace and Operating RequirementsMedium
A technician is flying a small UAS to inspect a 300-foot radio tower. The aircraft will remain within 400 feet laterally of the tower structure throughout the flight. What is the maximum altitude, in feet AGL, the technician may legally fly under the structure exception in 14 CFR 107.51?
- A700 feet AGL
- B400 feet AGL
- C1,200 feet AGL
- D500 feet AGL
Show answer & explanationAnswer & explanation
Correct answer: A. 700 feet AGL
Under the structure exception, a small UAS may fly no higher than 400 feet above the structure's immediate uppermost limit if remaining within a 400-foot radius of the structure. Since the tower is 300 feet tall, the maximum altitude is 300 + 400 = 700 feet AGL.
Why the other options are wrong
- B. 400 feet ignores the structure exception that allows exceeding the standard limit.
- C. 1,200 feet miscalculates by adding the tower height twice or misapplying the formula.
- D. 500 feet does not correctly apply the 400-foot addition to the structure's height.
Structure Exception Altitude Calculation
Within 400 feet laterally of a structure, a sUAS may fly up to 400 feet above the structure's uppermost point.
- Applies only within 400 ft lateral distance of the structure
- Formula: structure height + 400 ft = max altitude AGL
- Does not apply to natural terrain features
Memory trick: 'Tower plus 400' is your ticket to climb higher.