200 feet AGL there are numerous power lines, antenna towers, etc., that are not marked and lighted as
obstructions and; therefore, may not be seen in time to avoid a collision. Notices to Air Missions (NOTAMs) are
issued on those lighted structures experiencing temporary light outages. However, some time may pass before
the FAA is notified of these outages, and the NOTAM issued, thus pilot vigilance is imperative.
b. Antenna Towers. Extreme caution should be exercised when flying less than 2,000 feet AGL because of
numerous skeletal structures, such as radio and television antenna towers, that exceed 1,000 feet AGL with some
extending higher than 2,000 feet AGL. Most skeletal structures are supported by guy wires which are very
difficult to see in good weather and can be invisible at dusk or during periods of reduced visibility. These wires
can extend about 1,500 feet horizontally from a structure; therefore, all skeletal structures should be avoided
horizontally by at least 2,000 feet. Additionally, new towers may not be on your current chart because the
information was not received prior to the printing of the chart.
c. Overhead Wires. Overhead transmission and utility lines often span approaches to runways, natural
flyways such as lakes, rivers, gorges, and canyons, and cross other landmarks pilots frequently follow such as
highways, railroad tracks, etc. As with antenna towers, these high voltage/power lines or the supporting
structures of these lines may not always be readily visible and the wires may be virtually impossible to see under
certain conditions. In some locations, the supporting structures of overhead transmission lines are equipped with
unique sequence flashing white strobe light systems to indicate that there are wires between the structures.
However, many power lines do not require notice to the FAA and, therefore, are not marked and/or lighted. Many
of those that do require notice do not exceed 200 feet AGL or meet the Obstruction Standard of 14 CFR Part 77
and, therefore, are not marked and/or lighted. All pilots are cautioned to remain extremely vigilant for these
power lines or their supporting structures when following natural flyways or during the approach and landing
phase. This is particularly important for seaplane and/or float equipped aircraft when landing on, or departing
from, unfamiliar lakes or rivers.
d. Other Objects/Structures. There are other objects or structures that could adversely affect your flight
such as construction cranes near an airport, newly constructed buildings, new towers, etc. Many of these
structures do not meet charting requirements or may not yet be charted because of the charting cycle. Some
structures do not require obstruction marking and/or lighting and some may not be marked and lighted even
though the FAA recommended it.
7-6-5. Avoid Flight Beneath Unmanned Balloons
a. The majority of unmanned free balloons currently being operated have, extending below them, either a
suspension device to which the payload or instrument package is attached, or a trailing wire antenna, or both.
In many instances these balloon subsystems may be invisible to the pilot until the aircraft is close to the balloon,
thereby creating a potentially dangerous situation. Therefore, good judgment on the part of the pilot dictates that
aircraft should remain well clear of all unmanned free balloons and flight below them should be avoided at all
times.
b. Pilots are urged to report any unmanned free balloons sighted to the nearest FAA ground facility with which
communication is established. Such information will assist FAA ATC facilities to identify and flight follow
unmanned free balloons operating in the airspace.
7-6-6. Unmanned Aircraft Systems
a. Unmanned Aircraft Systems (UAS), formerly referred to as "Unmanned Aerial Vehicles" (UAVs) or
"drones," are having an increasing operational presence in the NAS. Once the exclusive domain of the military,
UAS are now being operated by various entities. Although these aircraft are "unmanned," UAS are flown by a
remotely located pilot and crew. Physical and performance characteristics of unmanned aircraft (UA) vary
greatly and unlike model aircraft that typically operate lower than 400 feet AGL, UA may be found operating
at virtually any altitude and any speed. Sizes of UA can be as small as several pounds to as large as a commercial
transport aircraft. UAS come in various categories including airplane, rotorcraft, powered-lift (tilt-rotor), and

Potential Flight Hazards

7-6-3