331:
130:
is set to an agreed baseline pressure under certain circumstances in which the aircraft’s altimeter would be unable to give a useful altitude readout. Examples would be landing at a high altitude or near sea level under conditions of exceptionally high air pressure. Old altimeters were typically
1001:
737:
126:, pressure altitude is the height above a standard datum plane (SDP), which is a theoretical level where the weight of the atmosphere is 29.921 inches of mercury (1,013.2 mbar; 14.696 psi) as measured by a barometer. It indicates altitude obtained when an
806:
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limited to displaying the altitude when set between 950 mb and 1030 mb. Standard pressure, the baseline used universally, is 1013.25
996:{\displaystyle {\begin{aligned}{\text{PA}}&=500+1000\times (29.92-29.32)\\&=500+1000\times 0.6\\&=500+600\\&=1100.\end{aligned}}}
1009:
report the pressure altitude to air traffic control; corrections for atmospheric pressure variations are applied by the recipient of the data.
732:{\displaystyle {\begin{aligned}{\text{PA}}&=500+30\times (1013-993)\\&=500+30\times 20\\&=500+600\\&=1100.\end{aligned}}}
143:(MSL) in the ISA. Pressure altitude is primarily used in aircraft-performance calculations and in high-altitude flight (i.e., above the
352:
378:
32:
1098:
356:
481:
exams describe a process for finding the pressure altitude (in feet) using one of the following rule of thumb formulae.
53:
341:
360:
345:
801:{\displaystyle {\text{Pressure altitude (PA)}}={\text{Elevation}}+1000\times (29.92-{\text{Altimeter setting}}).}
392:
478:
1012:
The relationship between static pressure and pressure altitude is defined in terms of properties of the ISA.
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539:{\displaystyle {\text{Pressure altitude (PA)}}={\text{Elevation}}+30\times (1013-{\text{QNH}}).}
219:{\displaystyle p=1013.25\left(1-{\frac {h}{44307.694{\text{ m}}}}\right)^{5.25530}{\text{ hPa}}}
136:
1036:
239:
743:
1031:
140:
42:(NOAA) published the following formula for directly converting atmospheric pressure in
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302:{\displaystyle p=1013.25\exp \left({\frac {-h}{8431{\text{ m}}}}\right){\text{ hPa}}}
235:
132:
746:, as common in the United States, Canada, and Japan, the following formula is used:
1082:
Pilot’s
Handbook of Aeronautical Knowledge (FAA-H-8083-25B), 2016, Chapter 4, p 4-4
1026:
144:
398:. The term refers to the indicated altitude at the landing runway threshold when
330:
47:
43:
467:
127:
123:
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35:(ISA) model predicts to have the same pressure as the observed value.
470:
window. It is the pressure altitude at the landing runway threshold.
395:
139:(inHg). This setting is equivalent to the atmospheric pressure at
1021:
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135:(hPa), which is equivalent to 1013.25 mb or 29.92
484:
Internationally, pressure altitude is approximated as:
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238:. This may be interpreted as the lowest terms of the
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Altitude at which atmosphere has a specified pressure
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1042:Standard conditions for temperature and pressure
40:National Oceanic and Atmospheric Administration
8:
155:Solving the equation for the pressure gives
359:. Unsourced material may be challenged and
811:For example, if the airfield elevation is
549:For example, if the airfield elevation is
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379:Learn how and when to remove this message
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872:{\displaystyle 29.32~\mathrm {inHg} }
459:{\displaystyle 29.92~\mathrm {inHg} }
422:{\displaystyle 1013.25~\mathrm {mb} }
7:
357:adding citations to reliable sources
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835:{\displaystyle 500~\mathrm {ft} }
608:{\displaystyle 993~\mathrm {mb} }
573:{\displaystyle 500~\mathrm {ft} }
113:{\displaystyle h=145366.45\left.}
33:International Standard Atmosphere
329:
1007:Aircraft Mode “C” transponders
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1:
842:and the altimeter setting is
85:Station pressure in millibars
46:(mb) to pressure altitude in
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473:Most aviation texts for
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758:Pressure altitude (PA)
742:If the altimeter uses
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496:Pressure altitude (PA)
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1099:Altitudes in aviation
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468:altimeter's Kollsman
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353:improve this section
315:exponential function
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21:atmospheric pressure
1067:"Pressure Altitude"
145:transition altitude
1047:Barometric formula
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789:Altimeter setting
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744:inches of mercury
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393:aeronautical code
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137:inches of mercury
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25:pressure altitude
23:measurement, the
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1037:Density altitude
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240:Taylor expansion
234:refers to hecto-
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151:Inverse equation
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27:is the imputed
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1032:Cabin altitude
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466:is set in the
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141:mean sea level
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338:This section
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1027:Flight level
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390:
375:
369:January 2024
366:
351:Please help
339:
154:
133:hectopascals
121:
37:
24:
18:
1053:References
391:QNE is an
952:×
924:−
915:×
785:−
776:×
766:Elevation
688:×
660:−
651:×
523:−
514:×
504:Elevation
340:does not
296: hPa
272:−
262:
213: hPa
190:44307.694
181:−
128:altimeter
75:−
64:145366.45
44:millibars
31:that the
19:Given an
1093:Category
1016:See also
580:and the
124:aviation
98:0.190284
29:altitude
879:, then
615:, then
406:1013.25
361:removed
346:sources
313:is the
284: m
256:1013.25
207:5.25530
194: m
169:1013.25
88:1013.25
853:
822:
595:
560:
440:
409:
396:Q code
309:where
236:Pascal
226:where
50:(ft):
1070:(PDF)
987:1100.
927:29.32
921:29.92
850:29.32
782:29.92
723:1100.
437:29.92
949:1000
912:1000
773:1000
657:1013
520:1013
477:and
344:any
342:cite
280:8431
48:feet
38:The
1022:QNH
974:600
968:500
955:0.6
943:500
906:500
819:500
710:600
704:500
679:500
663:993
642:500
592:993
584:is
582:QNH
557:500
527:QNH
479:CPL
475:PPL
429:or
355:by
321:QNE
311:exp
259:exp
242:of
232:hPa
147:).
122:In
1095::
895:PA
691:20
685:30
648:30
631:PA
511:30
317:.
1072:.
984:=
971:+
965:=
946:+
940:=
930:)
918:(
909:+
903:=
866:g
863:H
860:n
857:i
829:t
826:f
796:.
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779:(
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762:=
720:=
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701:=
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676:=
666:)
654:(
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639:=
602:b
599:m
567:t
564:f
534:.
531:)
517:(
508:+
500:=
453:g
450:H
447:n
444:i
416:b
413:m
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376:(
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367:(
363:.
349:.
291:)
275:h
266:(
253:=
250:p
228:m
202:)
186:h
178:1
174:(
166:=
163:p
108:.
104:]
93:)
80:(
72:1
68:[
61:=
58:h
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