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AIM 

4/20/23

 

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Potential Flight Hazards

lighter

than

air. Propulsion systems of UAS include a broad range of alternatives from piston powered and

turbojet engines to battery and solar

powered electric motors.

b.

To ensure segregation of UAS operations from other aircraft, the military typically conducts UAS

operations within restricted or other special use airspace. However, UAS operations are now being approved in
the NAS outside of special use airspace through the use of FAA

issued Certificates of Waiver or Authorization

(COA) or through the issuance of a special airworthiness certificate. COA and special airworthiness approvals
authorize UAS flight operations to be contained within specific geographic boundaries and altitudes, usually
require coordination with an ATC facility, and typically require the issuance of a NOTAM describing the
operation to be conducted. UAS approvals also require observers to provide “see

and

avoid” capability to the

UAS crew and to provide the necessary compliance with 14 CFR Section 91.113. For UAS operations approved
at or above FL180, UAS operate under the same requirements as that of manned aircraft (i.e., flights are operated
under instrument flight rules, are in communication with ATC, and are appropriately equipped).

c.

UAS operations may be approved at either controlled or uncontrolled airports and are typically

disseminated by NOTAM. In all cases, approved UAS operations must comply with all applicable regulations
and/or special provisions specified in the COA or in the operating limitations of the special airworthiness
certificate. At uncontrolled airports, UAS operations are advised to operate well clear of all known manned
aircraft operations. Pilots of manned aircraft are advised to follow normal operating procedures and are urged
to monitor the CTAF for any potential UAS activity. At controlled airports, local ATC procedures may be in place
to handle UAS operations and should not require any special procedures from manned aircraft entering or
departing the traffic pattern or operating in the vicinity of the airport.

d.

In addition to approved UAS operations described above, a recently approved agreement between the FAA

and the Department of Defense authorizes small UAS operations wholly contained within Class G airspace, and
in no instance, greater than 1200 feet AGL over military owned or leased property. These operations do not
require any special authorization as long as the UA remains within the lateral boundaries of the military
installation as well as other provisions including the issuance of a NOTAM. Unlike special use airspace, these
areas may not be depicted on an aeronautical chart.

e.

There are several factors a pilot should consider regarding UAS activity in an effort to reduce potential flight

hazards. Pilots are urged to exercise increased vigilance when operating in the vicinity of restricted or other
special use airspace, military operations areas, and any military installation. Areas with a preponderance of UAS
activity are typically noted on sectional charts advising pilots of this activity. Since the size of a UA can be very
small, they may be difficult to see and track. If a UA is encountered during flight, as with manned aircraft, never
assume that the pilot or crew of the UAS can see you, maintain increased vigilance with the UA and always be
prepared for evasive action if necessary. Always check NOTAMs for potential UAS activity along the intended
route of flight and exercise increased vigilance in areas specified in the NOTAM.

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7. Mountain Flying

a.

Your first experience of flying over mountainous terrain (particularly if most of your flight time has been

over the flatlands of the Midwest) could be a 

never-to-be-forgotten nightmare

 if proper planning is not done and

if you are not aware of the potential hazards awaiting. Those familiar section lines are not present in the
mountains; those flat, level fields for forced landings are practically nonexistent; abrupt changes in wind
direction and velocity occur; severe updrafts and downdrafts are common, particularly near or above abrupt
changes of terrain such as cliffs or rugged areas; even the clouds look different and can build up with startling
rapidity. Mountain flying need not be hazardous if you follow the recommendations below.

b. File a Flight Plan.

Plan your route to avoid topography which would prevent a safe forced landing. The

route should be over populated areas and well known mountain passes. Sufficient altitude should be maintained
to permit gliding to a safe landing in the event of engine failure.

c.

Don’t fly a light aircraft when the winds aloft, at your proposed altitude, exceed 35 miles per hour. Expect

the winds to be of much greater velocity over mountain passes than reported a few miles from them. Approach