static system static system system pressure sensitive instruments aviation determine aircraft number altitude altitude trend static system generally consists tube static port static instruments equipment measure forces acting vehicle function temperature density pressure fluid operating instruments connected air data computers flight data altitude cabin controllers switches errors static system readings extremely dangerous information obtained static system altitude potentially safety critical commercial airline disasters traced failure static system static pressure static system instruments uses principle air pressure gradient works measuring pressures pressure differences values assess speed altitude pressures measured static port static pressure tube pressure static pressure measurements pressure determine pressure pressure obtained tube pressure measure ram air pressure air pressure created vehicle motion air tube ideal conditions equal pressure called total pressure tube located wing section aircraft facing forward opening exposed relative wind tube location ram air pressure accurately measured distorted aircraft structure increases ram air pressure increased translated indicator static pressure static pressure obtained static port static port flush mounted hole fuselage aircraft located access air flow relatively area aircraft single static port situations aircraft static port usually located fuselage positioning average pressure taken allows accurate readings specific flight situations alternative static port located inside cabin aircraft backup external static port blocked static tube effectively static ports probe incorporates second tube tubes pressure sampling holes sides probe outside direct measure static pressure aircraft climbs static pressure decrease multiple pressure static systems incorporate single contain multiple pressure ports allow sensing air pressure angle attack angle data depending design air data referred hole hole air data differential pressure sensing techniques produce angle attack angle indications static instrument static system pressures interpretation static instruments explanations explain traditional mechanical instruments modern aircraft use air data computer rate climb altitude number aircraft receive total static pressure independent tubes static ports aircraft flight data computer compares information computers checks standby instruments instruments employed case problems primary instruments indicator indicator connected static pressure sources difference pressure static pressure called dynamic pressure greater dynamic pressure higher reported traditional mechanical indicator contains pressure connected tube case static port higher speed higher ram pressure pressure exerted larger needle movement mechanical pressure known barometric determine changes air pressure occur aircraft altitude changes pressure prior flight register pressure altitude sea level instrument case vent static port inside instrument sealed pressure case decreases internal expands translated determination altitude reverse true descending higher lower altitudes main errors produced error error instruments error position error temperature error barometric error jump aircraft designed operate speeds incorporate ratio true relation speed sound aircraft limited maximum number fly known limit number displayed fraction vertical speed indicator known vertical speed indicator vertical velocity indicator static instrument determine aircraft flying level flight vertical speed specifically shows rate climb rate descent measured feet minute meters second vertical speed measured mechanical located instrument area surrounding static port leak known restricted aircraft begins increase altitude begin contract rate faster leak causing needle positive vertical speed reverse situation true aircraft descending leak varies model model average time pressure seconds static errors situations affect accuracy static instruments involve failures static system classified system result faulty instrument placement environmental factors classified inherent errors system blocked tube blocked tube static problem affect blocked tube cause indicator register increase aircraft climbs actual constant caused pressure system remaining constant atmospheric pressure static pressure decreasing reverse indicator decrease aircraft descends tube susceptible ice water insects reason aviation regulatory agencies recommend tube checked prior flight prevent tubes equipped heating element heated tube required aircraft instrument flight aircraft experimental amateur built blocked static port blocked static port situation affects static instruments common causes blocked static port airframe blocked static port cause freeze constant value altitude static port blocked vertical speed indicator frozen zero change vertical speed increases decreases indicator reverse error occurs tube cause read actually aircraft climbs aircraft descending reported aircraft alternative static source available selected cockpit inherent errors inherent errors fall categories affecting different instruments density errors affect instruments altitude type error caused variations pressure temperature atmosphere error arise impact pressure cause air tube standard sea level pressure altitude equation correctly accounts compression error sea level higher altitudes compression correctly accounted cause instrument read greater equivalent correction obtained chart error significant altitudes feet greater knots error caused mechanical properties located instruments determine pressure differences physical properties resist change retaining given shape external forces changed reversal errors caused false static pressure reading false reading caused large changes aircraft pitch large change pitch cause showing movement opposite direction reversal errors primarily affect vertical speed position errors class inherent errors position error position error produced aircraft static pressure different air pressure remote aircraft error caused air flowing past static port speed different aircraft true position errors provide positive negative errors depending factors factors include angle attack aircraft weight acceleration aircraft configuration case helicopters categories position errors fixed errors variable errors fixed errors defined errors specific particular model aircraft variable errors caused external factors deformed panels flow air particular situations aircraft errors errors caused fact changes static dynamic pressure outside aircraft require finite time way affect type error depends length diameter volume inside error significant time altitude changing concern steady level flight static related disasters december flight boeing crashed northwest international airport climb route buffalo international airport tubes atmospheric february flight crashed sea shortly takeoff incorrect readings indicator suspected cause blocked tube confirmed airplane wreck recovered october flight crashed static ports static ports left aircraft taped aircraft cleaned job tape removed february bomber crash guam caused moisture sensors june french air safety authority said tube contributing factor crash flight
Pitot-static system