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Instrument Flying Handbook
Emergency Operations
Pitot/Static System Failure
Communication/Navigation System Malfunction

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Instrument Flying
Handbook

Preface

Table of Contents

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

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

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
Operations

Vacuum Failure.
Figure 11-8. Vacuum Failure.

Pitot/Static System Failure

A pitot or static system failure can also cause erratic and
unreliable instrument indications. When a static system
problem occurs, it affects the ASI, altimeter, and the VSI.
In most aircraft, provisions have been made for the pilot to
select an alternate static source. Check the POH/AFM for
the location and operation of the alternate static source. In
the absence of an alternate static source, in an unpressurized
aircraft, the pilot could break the glass on the VSI The VSI
is not required for instrument flight, and breaking the glass
provides the altimeter and the ASI a source of static pressure,
This procedure could cause additional instrument errors.

Communication/Navigation System Malfunction

Avionics equipment has become very reliable, and the
likelihood of a complete communications failure is remote.
However, each IFR flight should be planned and executed in
anticipation of a two-way radio failure. At any given point
during a flight, the pilot must know exactly what route to fly,
what altitude to fly, and when to continue beyond a clearance
limit, Title 14 of the Code of Federal Regulations (14 CFR)
part 91 describes the procedures to be followed in case of a
two-way radio communications failure. If operating in VFR
conditions at the time of the failure, the pilot should continue
the flight under VFR and land as soon as practicable. If the
failure occurs in IFR conditions, or if VFR conditions cannot
be maintained, the pilot must continue the flight:

1. Along the route assigned in the last ATC clearance
received:

2. If being radar vectored, by the direct route from the
point of radio failure to the fix, route, or airway specified
in the vector clearance;

3. In the absence of an assigned route, by the route
that ATC has advised may be expected in a further
clearance; or

4. In the absence of an assigned route or a route that ATC
has advised may be expected in a further clearance,
by the route filed in the flight plan.

The pilot should maintain the highest of the following
altitudes or flight levels for the route segment being flown:

1. The altitude or flight level assigned in the last ATC
clearance received;

2. The minimum altitude (converted, if appropriate, to
minimum flight level as prescribed in part 91 for IFR
operations); or

3. The altitude or flight level ATC has advised may be
expected in a further clearance.

In addition to route and altitude, the pilot must also plan the
progress of the flight to leave the clearance limit.

1. When the clearance limit is a fix from which an
approach begins, commence descent or descent
and approach as close as possible to the expect-
further-clearance time if one has been received. If an
expect-further-clearance time has not been received,
commence descent or descent and approach as close as
possible to the estimated time of arrival as calculated
from the filed or amended (with ATC) estimated time
en route.

 
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