Instruments Flashcards
How does warm air affect indicated altitude?
Will cause indicated altitude to be > true altitude (warm air increases press) [altimeter does not correct for nonstandard temp]
“from hot to cold, look out below”
Press change with altitude?
Change with temp?
Decrease as increase elevation at 1’ per 1000 feet
More rapid in colder air
Field elevation should read XX feet when baro is set to ATIS
= or - 75 feet
Standard rate turn
How to calculate for gyro?
2 min to complete 360 deg (or 3 deg/sec)
For gyro:
drop zero, add 7
eg 100 –> 17 deg, 110 –> 18 deg, 120 –> 19 deg
Dip/compass errors
- acceleration
- northern turning error
ANDS: Acceleration (on West-East headings) :
accel –> shows turn to the North,
decel –> shows turn to the South
UNOS: North turning error Undershoots (lag) north Overshoots south (if you turn while heading south, compress will show faster rate) or UNOS (undershoot N, overshoot S)
Blocked pitot
Blocked pitot and drain
Airspeed = constant and dropping, all else OK. Airspeed = reads high if climbing, low in decent*, all else normal
*Trapped press is making air speed act like an altimeter
Blocked static
altimeter -stuck at altitude when blocked
and VSI - stuck
airspeed - reads low during climb and vice versa (expected)
If you use the Alternate Static, what do you see?
press in cockpit is lower, so performances “improves”
Altimeter - higher; Airspeed - greater; VSI- climbs
VOR check
VOT
Airborne
dual
VOT (at airport, see AFD): turn TO, then FROM, must be +-4 deg
airborne: +-6 degrees
dual: tune to same VOR, max is 4 degree
VOR scale and full deflection
each dot is 2 deg
“30 Mile Rule” Each dot = 1 mile at 30 miles
ILS contains 4 elements
Outer, middle, inner markets
Glideslope, localizer, marker beacons, approach lites
Outer: 3-7 miles out; blue, hear dashes
Middle: 0.5 mile, 200 feet; amber, dash/dots
Inner: white, fast dot sound
Cold air altimeter effects
Indicated can be much lower than actual because cold air is extremely dense. See Correction Chart in AIM (7-2-3)
How does an altimeter work?
aneroid wafers expand or contract with changing atmospheric conditions
Limitations of altimeter with temp and nonstandard pressure?
Low standard press (or cold day) - reads higher than actual
Remember: High to low, or hot to cold - look out below
Errors of an airspeed indicator?
1) static port affected by air flow
2) density error: (change in altitude or temp not compensated)
3) Compressibility error: air packs in static at speeds > 180 kts
Standard lapse rate is?
eg what is freezing level at airport that is 1200 AGL, 6deg C?
2 deg per 1000 feet
0 degrees is at 3000, so 3000+1200=4200 feet
Which instruments use a gyro?
attitude indicator
heading indicator
turn coordinator
Slip skid
Slip - ball inside turn, not enough rudder
Skid - ball outside turn, too much rudder
Types of compass errors
Deviation - demons inside
Variation - earth mag disturbance, corrected by isogonic lines
Oscillation - cause by turbulance
Dip errors
if you change heading 360 to 330, how long is this turn?
30 deg / 3 = 10 sec
How do you check VOR with a VOT (VOR test signal)?
remember cessna 182
turn to 108, should show 180 and TO
Emergency transponder codes?
7500 - hijack
7600 - comm
7700 - emergency
What altitude does Mode C transponder transmit?
not the one on your altimeter. it is preset to 29.92
Full deflection of VOR is
Full deflection of CDI for a localizer?
10 degrees
2.5 degree (4x greater than VOR)
What if you receive VOR code every 30 seconds
DME is operative, VOR is NOT.
VOR effective distances? What’s max distance if off an airway?
terminal - 25 miles
low - 40
high - 40 to 130
below 18000, no more that 80 NM
Elements of GPS
What is RAIM?
If RAIM is lost, can you continue IRF?
24 Navstar satellites, at least 5 in view
Receiver autonomous integrety monitoring - checks status and if corrupted info is present.
No, must have RAIM capability for accuracy.
Standard take off climb slope and distance
1:40 or 200 ft/nm
calculate by: GS/60 x 200 —> 120 kts GS = 400 FPM
If pitot block, only one instrument is affected?
Airspeed
if ram port blocked, drain open: slowly goes to 0
if both blocked: acts like an alterimeter
VSI basis?
has a “calibrated leak” that sensing pressure differential
block static shows?
airspeed: low in climb, hi in decent
altimeter & VSI: freeze
VOR distance off course
at 30 miles from VOR, each dot = 1 mile (at 60 miles, each is 2 miles)
WAAS full scale sensitivity
RNP
WAAS RNP (requd nav performance)
en route: 5 miles 2
terminal: 1 1
approach: 0.3 0.3
WAAS level of precision?
from 100 meters (non WAAS) to about 2 meters horizontal/vert
