261:
247:, and the ASI pointer will drop to a zero reading. If both the opening and drain holes are blocked, the ASI will not indicate any change in airspeed. However, the ASI pointer will show altitude changes, as the associated static pressure changes. If both the pitot tube and the static system are blocked, the ASI pointer will read zero. If the static ports are blocked but the pitot tube remains open, the ASI will operate, but inaccurately.
270:
113:
224:
410:
401:
778:
752:
729:
462:
104:
453:
95:
239:
ground, and hence shows a reading of zero. When the aircraft is moving forward, air entering the pitot tube is at a greater pressure than the static line, which flexes the diaphragm, moving the pointer. The ASI is checked before takeoff for a zero reading, and during takeoff that it is increasing appropriately.
136:
The ASI has standard colour-coded markings to indicate safe operation within the limitations of the aircraft. At a glance, the pilot can determine a recommended speed (V speeds) or if speed adjustments are needed. Single and multi-engine aircraft have common markings. For instance, the green arc
238:
The ASI is the only flight instrument that uses both the static system and the pitot system. Static pressure enters the ASI case, while total pressure flexes the diaphragm, which is connected to the ASI pointer via mechanical linkage. The pressures are equal when the aircraft is stationary on the
286:(mph)). The pilot sets the pressure altitude and air temperature in the top window using the knob. Based on that, the white background scale in the lower left window moves to give true airspeed. Right – Airspeed indicator with Machmeter, including moveable pointers (
215:
242:
The pitot tube may become blocked, because of insects, dirt or failure to remove the pitot cover. A blockage will prevent ram air from entering the system. If the pitot opening is blocked, but the drain hole is open, the system pressure will drop to
782:
756:
733:
443:
Similarly, the Lift
Reserve Indicator (LRI) provides a measure of the amount of lift being generated. It uses a pressure differential system to provide the pilot with a visual representation of reserve lift available.
179:
The ASI in multi-engine aircraft includes two additional radial markings, one red and one blue, associated with potential engine failure. The radial red line near the bottom of green arc indicates
680:
707:
821:
628:
610:
506:
71:
1042:
169:, used for approaches and landings. The yellow arc cautions that flight should be conducted in this range only in smooth air, while the red line (
971:
428:(AOA) determines when an aircraft will stall. For a particular configuration, it is a constant independent of weight, bank angle, temperature,
486:
583:
473:
with the ASI in the form of "Airspeed Tape", including color coded ranges (left), and a combined ASI and
Machmeter for a jet aircraft (right)
440:
as a means for monitoring the onset of the critical AOA. The AOA indicator will show the current AOA and its proximity to the critical AOA.
304:), is read directly off the ASI. It has no correction for air density variations, installation or instrument errors. Calibrated airspeed (
991:
976:
646:
966:
814:
553:
433:
761:
694:
1037:
930:
889:
712:. U.S. Government Printing Office, Washington D.C.: U.S. Federal Aviation Administration. 2003. FAA AC 61-23C. Archived from
278:
Left – An airspeed indicator for an aeroplane. Indicated airspeed is displayed on the black background (in this case both in
328:. TAS increases as altitude increases, as air density decreases. TAS may be determined via a flight computer, such as the
685:. U.S. Government Printing Office, Washington D.C.: U.S. Federal Aviation Administration. 2004. FAA-8083-3A. Archived from
1027:
738:
686:
807:
787:
713:
702:. U.S. Government Printing Office, Washington D.C.: U.S. Federal Aviation Administration. 2005-11-25. FAA-H-8083-15.
935:
925:
496:
950:
793:
770:
744:
838:
125:
labelled, and Multi-engine ASI (centre) with blue and red radial lines, as well as (right) showing knots only
894:
79:
1047:
996:
470:
424:
An aeroplane can stall at any speed, so monitoring the ASI alone will not prevent a stall. The critical
74:, however knots (kt) is currently the most used unit. The ASI measures the pressure differential between
437:
945:
300:
There are four types of airspeed that can be remembered with the acronym ICE-T. Indicated airspeed (
313:
309:
176:) at the top of the yellow arc indicates damage or structural failure may result at higher speeds.
75:
55:
920:
879:
830:
501:
491:
152:
86:. This difference in pressure is registered with the ASI pointer on the face of the instrument.
1032:
884:
260:
67:
43:
654:
361:
like piston-engined aircraft, but instead have a maximum operating speed expressed in knots,
899:
429:
384:
244:
986:
425:
325:
291:
269:
198:
187:
383:, with appropriate red lines. An ASI will include a red-and-white striped pointer, or "
336:
is to add 2 percent to the CAS for every 1,000 ft (300 m) of altitude gained.
904:
722:
511:
283:
63:
17:
387:", that automatically moves to indicate the applicable speed limit at any given time.
1021:
981:
721:
Installing and flying the Lift
Reserve Indicator, article and photos by Sam Buchanan
333:
344:
186:, the minimum indicated airspeed at which the aircraft can be controlled with the
112:
516:
369:
317:
279:
214:
59:
1006:
861:
324:) is CAS corrected for altitude and nonstandard temperature. TAS is used for
83:
871:
856:
846:
409:
380:
379:. Thus, a pilot of a jet aeroplane needs both an airspeed indicator and a
223:
1001:
521:
122:
51:
47:
940:
400:
799:
461:
103:
507:
316:(CAS) corrected for the compressibility of air at a non-trivial
803:
452:
329:
94:
137:
indicates the normal operating range of the aircraft, from
308:) is corrected for installation and instrument errors.
723:
http://home.hiwaay.net/~sbuc/journal/liftreserve.htm
959:
913:
870:
837:
332:. Some ASIs have a TAS ring. Alternatively, a
591:. U.S. Dept. of Transportation, FAA. 2016. 12-2
561:. U.S. Dept. of Transportation, FAA. 2016. 8-8
815:
190:inoperative. The radial blue line indicates
8:
197:, the speed for best rate of climb with the
391:Angle of attack and Lift Reserve Indicators
822:
808:
800:
789:Pilot's Handbook of Aeronautical Knowledge
709:Pilot's Handbook of Aeronautical Knowledge
555:Pilot's Handbook of Aeronautical Knowledge
585:Airplane Flying Handbook, FAA-H-8083-3B
534:
651:Sonex Builders & Pilots Foundation
578:
576:
487:Acronyms and abbreviations in avionics
548:
546:
544:
542:
540:
538:
418:LRI (left) and AOA Indicators (right)
7:
992:Integrated standby instrument system
436:. An AOA indicator provides stall
653:. Sonex Foundation. Archived from
25:
967:Air data inertial reference unit
781: This article incorporates
776:
755: This article incorporates
750:
732: This article incorporates
727:
617:. March 1944. pp. 117, mid page.
460:
451:
434:center of gravity of an aircraft
408:
399:
268:
259:
222:
213:
111:
102:
93:
1043:Navigational flight instruments
629:"How Aircraft Instruments Work"
611:"How Aircraft Instruments Work"
151:. The white arc indicates the
931:Horizontal situation indicator
890:Horizontal situation indicator
132:Colour-coded speeds and ranges
121:Single-engine ASI (left) with
1:
70:(m/s). The recommendation by
471:Primary Flight Display (PFD)
1064:
936:Inertial navigation system
926:Course deviation indicator
763:Instrument Flying Handbook
696:Instrument Flying Handbook
78:from the static port, and
497:Global Positioning System
794:United States Government
771:United States Government
745:United States Government
740:Airplane Flying Handbook
682:Airplane Flying Handbook
647:"Lift Reserve Indicator"
895:Turn and slip indicator
18:True airspeed indicator
997:Primary flight display
783:public domain material
757:public domain material
734:public domain material
635:. March 1944. pp. 116.
1038:Measuring instruments
438:situational awareness
1028:Aircraft instruments
946:Satellite navigation
314:calibrated airspeed
310:Equivalent airspeed
72:ICAO is to use km/h
56:kilometres per hour
921:Aircraft periscope
880:Attitude indicator
852:Airspeed indicator
831:Flight instruments
657:on 11 October 2018
502:Indicated airspeed
492:Flight instruments
320:. True airspeed (
251:Types of airspeeds
32:airspeed indicator
1015:
1014:
885:Heading indicator
155:operating range,
68:metres per second
44:flight instrument
27:Flight instrument
16:(Redirected from
1055:
941:Magnetic compass
900:Turn coordinator
824:
817:
810:
801:
797:
780:
779:
774:
768:
754:
753:
748:
731:
730:
717:
703:
701:
690:
667:
666:
664:
662:
643:
637:
636:
625:
619:
618:
607:
601:
600:
598:
596:
590:
580:
571:
570:
568:
566:
560:
550:
464:
455:
430:density altitude
412:
403:
272:
263:
245:ambient pressure
226:
217:
115:
106:
97:
21:
1063:
1062:
1058:
1057:
1056:
1054:
1053:
1052:
1018:
1017:
1016:
1011:
987:Head-up display
955:
909:
866:
833:
828:
786:
777:
775:
766:
760:
751:
749:
737:
728:
706:
699:
693:
679:
676:
674:Further reading
671:
670:
660:
658:
645:
644:
640:
633:Popular Science
627:
626:
622:
615:Popular Science
609:
608:
604:
594:
592:
588:
582:
581:
574:
564:
562:
558:
552:
551:
536:
531:
526:
482:
477:
476:
475:
474:
467:
466:
465:
457:
456:
426:angle of attack
422:
421:
420:
419:
415:
414:
413:
405:
404:
393:
377:
366:
359:
352:
342:
326:flight planning
298:
297:
296:
295:
275:
274:
273:
265:
264:
253:
236:
235:
234:
233:
229:
228:
227:
219:
218:
207:
199:critical engine
196:
188:critical engine
185:
175:
168:
161:
150:
143:
134:
129:
128:
127:
126:
118:
117:
116:
108:
107:
99:
98:
76:static pressure
46:indicating the
28:
23:
22:
15:
12:
11:
5:
1061:
1059:
1051:
1050:
1045:
1040:
1035:
1030:
1020:
1019:
1013:
1012:
1010:
1009:
1004:
999:
994:
989:
984:
979:
974:
969:
963:
961:
960:Related topics
957:
956:
954:
953:
948:
943:
938:
933:
928:
923:
917:
915:
911:
910:
908:
907:
905:Turn indicator
902:
897:
892:
887:
882:
876:
874:
868:
867:
865:
864:
859:
854:
849:
843:
841:
835:
834:
829:
827:
826:
819:
812:
804:
719:
718:
716:on 2015-07-01.
704:
691:
689:on 2011-06-30.
675:
672:
669:
668:
638:
620:
602:
572:
533:
532:
530:
527:
525:
524:
519:
514:
512:Position error
509:
504:
499:
494:
489:
483:
481:
478:
469:
468:
459:
458:
450:
449:
448:
447:
446:
417:
416:
407:
406:
398:
397:
396:
395:
394:
392:
389:
375:
364:
357:
350:
341:
338:
284:miles per hour
277:
276:
267:
266:
258:
257:
256:
255:
254:
252:
249:
232:ASI components
231:
230:
221:
220:
212:
211:
210:
209:
208:
206:
203:
194:
183:
173:
166:
159:
148:
141:
133:
130:
120:
119:
110:
109:
101:
100:
92:
91:
90:
89:
88:
80:total pressure
64:miles per hour
40:airspeed gauge
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
1060:
1049:
1048:Speed sensors
1046:
1044:
1041:
1039:
1036:
1034:
1031:
1029:
1026:
1025:
1023:
1008:
1005:
1003:
1000:
998:
995:
993:
990:
988:
985:
983:
982:Glass cockpit
980:
978:
975:
973:
970:
968:
965:
964:
962:
958:
952:
949:
947:
944:
942:
939:
937:
934:
932:
929:
927:
924:
922:
919:
918:
916:
912:
906:
903:
901:
898:
896:
893:
891:
888:
886:
883:
881:
878:
877:
875:
873:
869:
863:
860:
858:
855:
853:
850:
848:
845:
844:
842:
840:
836:
832:
825:
820:
818:
813:
811:
806:
805:
802:
798:
795:
791:
790:
784:
772:
765:
764:
758:
746:
742:
741:
735:
725:
724:
715:
711:
710:
705:
698:
697:
692:
688:
684:
683:
678:
677:
673:
656:
652:
648:
642:
639:
634:
630:
624:
621:
616:
612:
606:
603:
587:
586:
579:
577:
573:
557:
556:
549:
547:
545:
543:
541:
539:
535:
528:
523:
520:
518:
515:
513:
510:
508:
505:
503:
500:
498:
495:
493:
490:
488:
485:
484:
479:
472:
463:
454:
445:
441:
439:
435:
431:
427:
411:
402:
390:
388:
386:
385:barber's pole
382:
378:
371:
367:
360:
353:
346:
339:
337:
335:
334:rule of thumb
331:
327:
323:
319:
315:
311:
307:
303:
293:
289:
285:
281:
271:
262:
250:
248:
246:
240:
225:
216:
204:
202:
201:inoperative.
200:
193:
189:
182:
177:
172:
165:
158:
154:
147:
140:
131:
124:
114:
105:
96:
87:
85:
81:
77:
73:
69:
66:(MPH) and/or
65:
61:
57:
53:
49:
45:
41:
37:
33:
19:
914:Navigational
851:
839:Pitot-static
788:
762:
739:
726:
720:
714:the original
708:
695:
687:the original
681:
659:. Retrieved
655:the original
650:
641:
632:
623:
614:
605:
593:. Retrieved
584:
563:. Retrieved
554:
442:
423:
373:
362:
355:
348:
347:do not have
345:Jet aircraft
343:
340:Jet aircraft
321:
305:
301:
299:
287:
241:
237:
191:
180:
178:
170:
163:
156:
145:
138:
135:
62:(kn or kt),
39:
35:
31:
29:
517:Speedometer
370:Mach number
318:Mach number
1022:Categories
1007:Yaw string
872:Gyroscopic
862:Variometer
661:10 October
595:10 October
565:10 October
529:References
432:, and the
84:pitot tube
857:Machmeter
847:Altimeter
381:Machmeter
312:(EAS) is
290:) at the
282:(kn) and
205:Operation
82:from the
1033:Airspeed
1002:V speeds
522:V speeds
480:See also
123:V speeds
58:(km/h),
52:aircraft
48:airspeed
50:of an
785:from
767:(PDF)
759:from
736:from
700:(PDF)
589:(PDF)
559:(PDF)
292:bezel
280:knots
60:knots
42:is a
38:) or
977:EFIS
972:ECAM
951:SIGI
663:2018
597:2018
567:2018
368:and
354:and
288:bugs
153:flap
30:The
330:E6B
322:TAS
306:CAS
302:IAS
195:YSE
162:to
144:to
54:in
36:ASI
1024::
792:.
769:.
743:.
649:.
631:.
613:.
575:^
537:^
376:MO
372:,
365:MO
358:NE
351:NO
184:mc
174:NE
167:FE
160:SO
149:NO
142:S1
823:e
816:t
809:v
796:.
773:.
747:.
665:.
599:.
569:.
374:M
363:V
356:V
349:V
294:.
192:V
181:V
171:V
164:V
157:V
146:V
139:V
34:(
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
