MODE
MAP WPT AUX NRST
VOLTS 28.1
SATZ AMPS 0
RUDDER TRIM
L R
ELECTRICAL
61.9
10.0
27.4
NA V1 108.00 113.00
NA V2 108.00 110.60
134.000 118.000 COM1
123.800 118.000 COM2
WPT _ _ _ _ _ _ DIS _ _ . _ NM DTK _ _ _° TRK 360°
Figure 3-51. Aircrafts MFD when using TIS.
ALERTS
MAP - TRAFFIC MAP
TRAFFIC MODE
OPERA TE
FLAPS
ELEV
TRIM
UP
DN T A OFF SCALE
HDG UP
12NM
6NM
+05 +05
-03
Figure 5-53. Multi-function display (MFD).
Receiver-transmitter (RT)
Radar altimeter indicator
Figure 5-51. Components of a radar altimeter.
3,500'
3,500'
7 NM
Figure 5-52. Coverage provided by a traffic information system.
OFF
ALT
ON GND TST
SBY
FLT ID
CRSR FLT ID BRT
IDT
VFR
XPDR KT 73 TSD
Mode S Transponder
Mode S Sensor
Data link control display unit
Figure 3-52. Traffic information system concept.
Figure 5-54. Concept of the traffic information system.
Figure 3-51A. Theory of a typical alert system.Figure 5-55. Theory of a typical alert system.
Figure 5-56. A Skywatch System.Figure 3-51C. TAS600
SEL
MENU
RNG DATA BRT VIEW
NORM 2700 ft
1013mb
20 nm
+02
0.0
-05
Figure 5-57. Alert System by Avidyne (Ryan).
Figure 3-52. TCAS II
RNG 5 1
.5
.5 4
12 -05
Figure 5-58. An example of a resolution advisory being provided
to the pilot. In this case, the pilot is requested to climb, with 1,750
feet being the appropriate rate of ascent to avoid traffic conflict.
This visual indication plus the audio warning provide the pilot with
excellent traffic awareness that augments see-and-avoid practices.
TCAS II is a more sophisticated system which provides the
same information of TCAS I. It also analyzes the projected
flightpath of approaching aircraft and issues resolution
advisories to the pilot to resolve potential mid-air collisions.
Additionally, if communicating with another TCAS II
equipped aircraft, the two systems coordinate the resolution
alerts provided to their respective flight crews. [Figure 5-58]
Terrain Alerting Systems
Ground Proximity Warning System (GPWS)
An early application of technology to reduce controlled
flight into terrain (CFIT) was the GPWS. In airline use
since the early 1970s, GPWS uses the radio altimeter, speed,
and barometric altitude to determine the aircraft’s position
relative to the ground. The system uses this information in
determining aircraft clearance above the Earth and provides
limited predictability about aircraft position relative to rising
terrain. It does this based upon algorithms within the system
and developed by the manufacturer for different airplanes or
helicopters. However, in mountainous areas the system is
unable to provide predictive information due to the unusual
slope encountered.
This inability to provide predictive information was evidenced
in 1999 when a DH-7 crashed in South America. The crew
had a GPWS onboard, but the sudden rise of the terrain
rendered it ineffective; the crew continued unintentionally
into a mountain with steep terrain. Another incident involved
Secretary of Commerce Brown who, along with all on board,
was lost when the crew flew over rapidly rising terrain where
the GPWS capability is offset by terrain gradient. However,
the GPWS is tied into and considers landing gear status, flap
position, and ILS glideslope deviation to detect unsafe aircraft
operation with respect to terrain, excessive descent rate,
excessive closure rate to terrain, unsafe terrain clearance while
not in a landing configuration, excessive deviation below an
ILS glideslope. It also provides advisory callouts.
Generally, the GPWS is tied into the hot bus bar of the electrical
system to prevent inadvertent switch off. This was demonstrated
in an accident involving a large four-engine turboprop airplane.
While on final for landing with the landing gear inadvertently
up, the crew failed to heed the GPWS warning as the aircraft
crossed a large berm close to the threshold. In fact, the crew
attempted without success to shut the system down and attributed
the signal to a malfunction. Only after the mishap did the crew
realize the importance of the GPWS warning.
Terrain Awareness and Warning System (TAWS)
A TAWS uses GPS positioning and a database of terrain and
obstructions to provide true predictability of the upcoming
terrain and obstacles. The warnings it provides pilots are
both aural and visual, instructing the pilot to take specific
action. Because TAWS relies on GPS and a database of
terrain/obstacle information, predictability is based upon
aircraft location and projected location. The system is time
based and therefore compensates for the performance of the
aircraft and its speed. [Figure 5-59]
Head-Up Display (HUD)
The HUD is a display system that provides a projection of
navigation and air data (airspeed in relation to approach
reference speed, altitude, left/right and up/down glideslope)
on a transparent screen between the pilot and the windshield.
The concept of a HUD is to diminish the shift between
looking at the instrument panel and outside. Virtually any
Figure 5-59. A six-frame sequence illustrating the manner in which TAWS operates. A TAWS installation is aircraft specific and provides
warnings and cautions based upon time to potential impact with terrain rather than distance. The TAWS is illustrated in an upper left
window while aircrew view is provided out of the windscreen.
illustrates the aircraft in relation to the outside terrain while
and
illustrate the manner in which the TAWS system displays the terrain.
is providing a caution of terrain to be traversed, while
provides an illustration of a warning with an aural and textural advisory (red) to pull up.
also illustrates a pilot taking appropriate
action (climb in this case) while
illustrates that a hazard is no longer a factor.
Figure 5-60. A head-up display (HUD).
5 5
5 5
10 10
24 25 26 W
6 3
CRS
HDG
VOR2
- - . - NM
GSPD
59 KTS
VOR1
- - -
TRACK
29.89 IN
KDVT 25L
ON RWY 36L
Figure 3-54. A Head Up Display on a Gulfstream.
information desired can be displayed on the HUD if it is
available in the aircraft’s flight computer. The display for
the HUD can be projected on a separate panel near the
windscreen or as shown in Figure 5-60 on an eye piece. Other
information may be displayed, including a runway target in
relation to the nose of the aircraft, which allows the pilot to
see the information necessary to make the approach while
also being able to see out the windshield.
Required Navigation Instrument System
Inspection
Systems Preflight Procedures
Inspecting the instrument system requires a relatively small
part of the total time required for preflight activities, but its
importance cannot be overemphasized. Before any flight
involving aircraft control by instrument reference, the pilot
should check all instruments and their sources of power for
proper operation.
NOTE: The following procedures are appropriate for
conventional aircraft instrument systems. Aircraft equipped
with electronic instrument systems utilize different
procedures.
Before Engine Start
1. Walk-around inspection: Check the condition of all
antennas and check the pitot tube for the presence
of any obstructions and remove the cover. Check
the static ports to be sure they are free from dirt
and obstructions, and ensure there is nothing on the
structure near the ports that would disturb the air
flowing over them.
2. Aircraft records: Confirm that the altimeter and static
system have been checked and found within approved
limits within the past 24 calendar months. Check the
replacement date for the emergency locator transmitter
(ELT) batteries noted in the maintenance record, and
be sure they have been replaced within this time
interval.
3. Preflight paperwork: Check the Airport/Facility
Directory (A/FD) and all NOTAMs for the condition
and frequencies of all the navigation aid (NAVAIDs)
that are used on the flight. Handbooks, en route charts,
approach charts, computer and flight log should be
appropriate for the departure, en route, destination,
and alternate airports.
4. Radio equipment: Switches OFF.
5. Suction gauge: Proper markings as applicable if
electronic flight instrumentation is installed.
6. ASI: Proper reading, as applicable. If electronic
flight instrumentation is installed, check emergency
instrument.
7. Attitude indicator: Uncaged, if applicable. If electronic
flight instrumentation is installed, check emergency
system to include its battery as appropriate.
8. Altimeter: Set the current altimeter setting and ensure
that the pointers indicate the elevation of the airport.
9. VSI: Zero indication, as applicable (if electronic flight
instrumentation is installed).
10. Heading indicator: Uncaged, if applicable.
11. Turn coordinator: If applicable, miniature aircraft
level, ball approximately centered (level terrain).
12. Magnetic compass: Full of fluid and the correction
card is in place and current.
13. Clock: Set to the correct time and running.
14. Engine instruments: Proper markings and readings,
as applicable if electronic flight instrumentation is
installed.
15. Deicing and anti-icing equipment: Check availability
and fluid quantity.
16. Alternate static-source valve: Be sure it can be opened
if needed, and that it is fully closed.
17. Pitot tube heater: Check by watching the ammeter
when it is turned on, or by using the method specified
in the POH/AFM.
After Engine Start
1. When the master switch is turned on, listen to the
gyros as they spin up. Any hesitation or unusual noises
should be investigated before flight.
2. Suction gauge or electrical indicators: Check the
source of power for the gyro instruments. The suction
developed should be appropriate for the instruments
in that particular aircraft. If the gyros are electrically
driven, check the generators and inverters for proper
operation.
3. Magnetic compass: Check the card for freedom of
movement and confirm the bowl is full of fluid.
Determine compass accuracy by comparing the
indicated heading against a known heading (runway
heading) while the airplane is stopped or taxiing
straight. Remote indicating compasses should also be
checked against known headings. Note the compass
card correction for the takeoff runway heading.
4. Heading indicator: Allow 5 minutes after starting
engines for the gyro to spin up. Before taxiing, or
while taxiing straight, set the heading indicator to
correspond with the magnetic compass heading. A
slaved gyrocompass should be checked for slaving
action and its indications compared with those of the
magnetic compass. If an electronic flight instrument
system is installed, consult the flight manual for proper
procedures.
5. Attitude indicator: Allow the same time as noted
above for gyros to spin up. If the horizon bar erects
to the horizontal position and remains at the correct
position for the attitude of the airplane, or if it begins
to vibrate after this attitude is reached and then slowly
stops vibrating altogether, the instrument is operating
properly. If an electronic flight instrument system
is installed, consult the flight manual for proper
procedures.
6. Altimeter: With the altimeter set to the current reported
altimeter setting, note any variation between the
known field elevation and the altimeter indication. If
the indication is not within 75 feet of field elevation,
the accuracy of the altimeter is questionable and
the problem should be referred to a repair station
for evaluation and possible correction. Because the
elevation of the ramp or hangar area might differ
significantly from field elevation, recheck when in
the run-up area if the error exceeds 75 feet. When
no altimeter setting is available, set the altimeter
to the published field elevation during the preflight
instrument check.
7. VSI: The instrument should read zero. If it does not,
tap the panel gently. If an electronic flight instrument
system is installed, consult the flight manual for proper
procedures.
8. Engine instruments: Check for proper readings.
9. Radio equipment: Check for proper operation and set
as desired.
10. Deicing and anti-icing equipment: Check operation.
Taxiing and Takeoff
Ensuring the functionality of the turn coordinator, heading
indicator, magnetic compass, and attitude indicator prior
to taxiing and takeoff is essential to flight safety. Runway
incursion is an incident at an airport that adversely affects
runway safety and pilots must mitigate this risk by ensuring
that all of the directional flight instruments are checked
properly before taxiing or taking off so that the position
of the aircraft in relation to the runway and other traffic is
always known.
1. Turn coordinator: During taxi turns, check the
miniature aircraft for proper turn indications. The ball
or slip/skid should move freely. The ball or slip/skid
indicator should move opposite to the direction of
turns. The turn instrument should indicate the direction
of the turn. While taxiing straight, the miniature
aircraft (as appropriate) should be level.
2. Heading indicator: Before takeoff, recheck the heading
indicator. If the magnetic compass and deviation card
are accurate, the heading indicator should show the
known taxiway or runway direction when the airplane
is aligned with them (within 5°).
3. Attitude indicator: If the horizon bar fails to remain
in the horizontal position during straight taxiing, or
tips in excess of 5° during taxi turns, the instrument is
unreliable. Adjust the miniature aircraft with reference
to the horizon bar for the particular airplane while on
the ground. For some tricycle-gear airplanes, a slightly
nose-low attitude on the ground gives a level flight
attitude at normal cruising speed.
Engine Shut Down
When shutting down the engine, note any abnormal
instrument indications.