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Instrument Flying Handbook
The Air Traffic Control System
Communication Procedures and Facilities

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Instrument Flying


Table of Contents

Chapter 1. Human Factors
Chapter 2. Aerodynamic Factors
Chapter 3. Flight Instruments
Chapter 4. Section I
Airplane Attitude Instrument
Using Analog Instrumentation
Chapter 4. Section II
Airplane Attitude Instrument
Using an Electronic Flight

Chapter 5. Section I
Airplane Basic
Flight Maneuvers
Using Analog Instrumentation
Chapter 5. Section II
Airplane Basic
Flight Maneuvers
Using an Electronic Flight

Chapter 6. Helicopter
Attitude Instrument Flying

Chapter 7. Navigation Systems
Chapter 8. The National
Airspace System

Chapter 9. The Air Traffic
Control System

Chapter 10. IFR Flight
Chapter 11. Emergency

The briefer sends a flight plan to the host computer at
the ARTCC (Center). After processing the flight plan,
the computer will send flight strips to the tower, to the
radar facility that will handle the departure route, and to
the Center controller whose sector the flight first enters.
Figure 9-6 shows a typical strip. These strips are delivered
approximately 30 minutes prior to the proposed departure
time. Strips are delivered to en route facilities 30 minutes
before the flight is expected to enter their airspace. If a
flight plan is not opened it will "time out" 2 hours after the
proposed departure time.

When departing an airport in Class G airspace, a pilot, receives
an IFR clearance from the AFSS by radio or telephone. It
contains either a clearance void time, in which case all aircraft
must be airborne prior to that time, or a release time. Pilots
should not take-off prior to the release time. Pilots can help
the controller by stating how soon they expect to be airborne.
If the void time is, for example, 10 minutes past the hour and
an aircraft is airborne at exactly 10 minutes past the hour,
the clearance is void, a pilot must take off prior to the void
time. A specific void time may be requested when filing a
flight plan.

ATC Towers
Several controllers in the tower cab are involved in handling
an instrument flight. Where there is a dedicated clearance
delivery position, that frequency is found in the A/FD and
on the instrument approach chart for the departure airport.
Where there is no clearance delivery position, the ground
controller performs this function. At the busiest airports, pre-
taxi clearance is required; the frequency for pie-taxi clearance
can be found in the A/FD. Taxi clearance should be requested
not more than 10 minutes before proposed taxi time.

It is recommended that pilots read their IFR clearance back to
the clearance delivery controller. Instrument clearances can
be overwhelming when attempting to copy them verbatim,
but they follow a format that allows a pilot to be prepared
when responding "Ready to copy." The format is: clearance
limit (usually the destination airport); route, including any
departure procedure; initial altitude; frequency (for departure

control); and transponder code. With the exception of the
transponder code, a pilot knows most of these items before
engine start. One technique for clearance copying is writing

Assume an IFR flight plan has been filed from Seattle,
Washington to Sacramento, California via V-23 at 7,000
feet. Traffic is taking off to the north from Seattle-Tacoma
(Sea-Tac) airport and, by monitoring the clearance delivery
frequency, a pilot can determine the departure procedure
being assigned to southbound flights. The clearance limit
is the destination airport, so write "SAC" after the letter C.
Write "SEATTLE TWO - V 23" after R for Route, because
departure control issued this departure to other flights. Write
"7" after the A, the departure control frequency printed on
the approach charts for Sea-Tac after F, and leave the space
after the letter T blank, the transponder code is generated by
computer and can seldom be determined in advance. Then,
call clearance delivery and report "Ready to copy."

As the controller reads the clearance, check it against what
is already written down; if there is a change, draw a line
through that item and write in the changed item. Chances
are the changes are minimal, and most of the clearance is
copied before keying the microphone. Still, it is worthwhile
to develop clearance shorthand to decrease the verbiage that
must be copied.

Pilots are required to have either the text of a departure
procedure (DP) or a graphic representation (if one is
available), and should review it before accepting a clearance.
This is another reason to find out ahead of time, which DP is
in use. If the DP includes an altitude or a departure control
frequency, those items are not. included in the clearance.

The last clearance received supersedes all previous clearances.
For example, if the DP says "Climb and maintain 2,000 feet,
expect, higher in 6 miles," but upon contacting the departure
controller a new clearance is received: "Climb and maintain
8,000 feet," the 2,000 feet restriction has been canceled. This
rule applies in both terminal and Center airspace.

Flight Strip.
Figure 9-6. Flight Strip.