6-1

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

Lesson objective - to discuss

UAV Operating Environments

including …• National airspace

• UAV implications

Objectives

Expectations - You will have a basic understanding of how national airspace rules drive UAV design and operations- This is a very complicated subject and you are not expected to commit any of this to memory

All countries have rules for how aircraft must operate in their airspace.

• Most follow guidelines developed by the International Civil Aviation Organization (ICAO)

• Rules apply to two types of airspace - Enroute airspace - the airways - Terminal airspace - around airports

Airspace rules are based on manned aircraft experience

• UAVs will have to fit into the established system

The system gives pilots, not air traffic control (ATC), primary responsibility for safe operation of their aircraft

6-2

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

Airspace Environment

• At a minimum all pilots are required to follow Visual Flight Rules (VFR) : allowed when visibility is good (called visual meteorological conditions or VMC)

• Certified instrument pilots can operate under Instrument Flight Rules (IFR) : required when visibility is poor (called instrument meteorological conditions or IMC) or when above 18Kft

- Under IFR it is assumed that a pilot cannot see other aircraft and air traffic control assumes responsibility for maintaining safe separation between IFR aircraft

• But in other than IMC, VFR and IFR aircraft will often share the same airspace. The basic airspace operating principle for both VFR and IFR traffic, therefore, is …..SEE AND AVOID……

UAVs must be equipped to do this

6-3

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

Basic rules

• Apply except when an aircraft is IFR • Generally describe what a pilot cannot do

- Fly close to the ground except to take off and land- Fly in or near clouds- Fly above certain speeds- Fly in certain types of controlled airspace without

permission (usually from an air traffic controller)- Etc.

• Also describe what a pilot should/must do- Example, fly at certain altitudes for certain headings

- Westerly headings at even altitudes + 500 ft- Easterly headings at odd altitudes + 500 ft

- Follow air traffic control instructions (except when safety is an issue)

6-4

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

Visual Flight Rules

• Generally describe what a pilot must do

- Comply with air traffic control instructions- Maintain assigned altitudes and headings- Follow approved flight plans- Report positions- Follow established procedures- Etc.

• Exceptions are related to flight safety

- A pilot does not have to accept air traffic control (ATC) instructions when flight safety is an issue

- The pilot is always in command

• IFR aircraft are also required to be in radio contact with ATC and to be equipped with encoding radio transponders that provide altitude information and make aircraft easy to track

6-5

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

Instrument Flight Rules

Two categories of airports

Controlled airports - Have sufficient traffic for a control tower and sometimes other services. Radio communication (contact) is mandatory. Airport size varies:

• Large airports- Operate under rules that are like IFR at all times- Multiple control functions

- Control tower - control near the airport (5 NM) - Approach and departure - control out to 30 NM

• Smaller airports- Mostly operate VFR- Control traffic out to 5 NM

Uncontrolled airports - No control tower. Radio contact not required. Operate VFR (See and Avoid!) except when IMC

6-6

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

Terminal airspace

6-7

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

Airport and terminal airspace (ICAO definitions)

Controlled airports

Class B - The largest airports that control traffic out to about 30 NM

Class C - larger airports with radar plus approach and departure control (out to about 10

NM)

Class D - an airport with a control tower only

Uncontrolled airports -

Class E - an airport with an instrument approach

Class F -

Class G - an airport with no instrument approach

Terminal airspace - cont’d

6-8

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

Enroute Airspace

Class A - Positive control airspace - from 18,000 feet above mean sea level (MSL) to 60,000 feet MSL. Only IFR traffic operate in Class A airspace.

Class E - Controlled airspace from 1200 feet above ground level (AGL) to 18,000 feet MSL. Also includes all airspace from 14,500-18,000 feet MSL. Both IFR and VFR traffic fly in Class E airspace.

Class G - Uncontrolled airspace from the surface to 1200 ft AGL. IFR aircraft don’t fly in Class G except when taking off and landing (from uncontrolled airports). - Also includes airspace above 60 Kft!

More ICAO definitions

6-9

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

The UAV Issue

• If all airspace were controlled and all traffic were IFR, UAVs would have fewer airspace problems

• UAV operators would function as virtual pilots

• IFR for departure, enroute and arrival• Transponders provide altitude and position track• On-board navigation provides data for other

position reports• Radio communication would be through the UAV

• Ground operation would still be a problem

• But this is not the case - UAVs have to deal with VFR traffic and operations- They must be equipped for “See and Avoid”

6-10

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

Current UAV status (military)

• Operation in military controlled airspace is not an issue• They sometimes shut down manned operations when

UAVs are operating near or on military air fields• Operations in civil airspace above 18Kft is not an issue

• All traffic is IFR• Operations below 18Kft is the issue

• Early military operations (cruise missile testing) had to use chase aircraft to ensure safe operations

• New rules are being negotiated• US UAVs are allowed to fly enroute through selected

(but not all) terminal airspace • Takeoff and landing is allowed from small fields at

planned times. Manned aircraft get radio warnings.

6-11

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

NASA taking lead in evaluating various manned-unmanned traffic avoidance schemes

Current UAV status (civil)

But the events of 9/11 may have a major effect on how non-military UAVs are allowed to operate in national air space

NASA News Release: 03-17, 24 March 2003

6-12

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

Future projection

• UAVs probably will initially be limited to IFR rules • Operations will be in and out of controlled fields where controllers are familiar with UAVs

• UAVs will use on board electro-optical sensors and collision avoidance systems (e.g. TCAS) to maintain separation from other traffic

• Manned aircraft will be kept away• Emergencies will be a problem - operations will shut down to accommodate unplanned arrival of a UAV

• Later VFR operations probably will be allowed• UAVs will operate (and be equipped for) flight in all types of airspace.

• Manned aircraft pilots will get used to them

6-13

Expectations

You should now understand the issues associated with UAV operating environments

- Current airspace rules limit UAV operations

- The rules will undergo change

- At a minimum UAVs will have to be equipped for manned IFR operations and have sensors to provide “see and avoid”

Design of UAV Systems

UAV operating environmentsc 2002 LM Corporation

6-14

IntermissionDesign of UAV Systems

UAV operating environmentsc 2002 LM Corporation