{"id":14486,"date":"2025-06-07T16:20:42","date_gmt":"2025-06-07T10:50:42","guid":{"rendered":"https:\/\/ibexaviation.com\/pilot-training\/?p=14486"},"modified":"2025-06-09T19:21:18","modified_gmt":"2025-06-09T13:51:18","slug":"artificial-horizon","status":"publish","type":"post","link":"https:\/\/ibexaviation.com\/pilot-training\/artificial-horizon\/","title":{"rendered":"Artificial Horizon (AH)"},"content":{"rendered":"\n<h2>Artificial Horizon<\/h2>\n\n\n\n<h3>Display of an Artificial Horizon<\/h3>\n\n\n\n<ul><li>Artificial horizon provides attitude of aircraft using a vertical axis gyro<\/li><li>The gyro spin axis is maintained vertical to earth surface by gravity<\/li><li>Gull wing etched on the outer glass moves with aircraft in pitch and roll<\/li><li>The horizon image attached to an earth gyro maintains its orientation<\/li><li>Nose up indication shows gull wing above the horizon<\/li><li>Gull wing attached to outer gimbal moves down by a guide pin system<\/li><li>Horizon bar attached to the inner gimbal retains its vertical position<\/li><li>Artificial horizon indications are limited to 60 and 110 degrees in pitch and roll<\/li><\/ul>\n\n\n\n<h3>Principle of Artificial Horizon<\/h3>\n\n\n\n<ul><li>Pitch-up indication is shown by gull wing above the horizon<\/li><li>Nose-up movement rotates the case and attached outer gimbal up<\/li><li>Guide pin protruding from the inner gimbal maintains the horizon bar down<\/li><li>Horizon bar is now below the gull-wing producing the nose-up indication<\/li><li>Pitch-down indication is shown by gull wing below the horizon<\/li><li>Nose-down movement rotates the case and attached outer gimbal down<\/li><li>Guide pin protruding from the inner gimbal maintains the horizon bar up<\/li><li>Horizon bar is now above the gull-wing producing the nose-down indication<\/li><\/ul>\n\n\n\n<h3>Self Correction in Air Driven Artificial Horizon<\/h3>\n\n\n\n<ul><li>Vertical gyro in artificial horizon cannot drift but can topple<\/li><li>Two pairs of pendulous vanes are designed to auto correct gyro topple<\/li><li>Topple of spin axis opens one wane and closes its opposite one<\/li><li>Imbalanced pressure of exiting air creates an external force<\/li><li>This force is precesses through 90 degrees to self correct topple<\/li><\/ul>\n\n\n\n<h3>Acceleration Errors Due to Self Correction<\/h3>\n\n\n\n<ul><li>Acceleration in level attitude induces errors due to self correct mechanism<\/li><li>Artificial horizon will indicate a false nose up attitude<\/li><li>Pitch error is due to the effect of acceleration on the pendulous vanes<\/li><li>Right wing will appear to be down on the instrument<\/li><li>Roll error is due to the inertia of the bottom-heavy rotor housing<\/li><li>Acceleration and deceleration will therefore result in false information<\/li><li>Pitch up with right bank during acceleration<\/li><li>Pitch down with left bank during deceleration<\/li><\/ul>\n\n\n\n<h3>Turning Errors Due to Self Correction<\/h3>\n\n\n\n<ul><li>Turns induce errors due to centripetal force on the artificial horizon<\/li><li>Turn through 90 deg &#8211; under-reads bank-angle &#8211; pitch up indication<\/li><li>Turns through 180 deg &#8211; correct bank-angle &#8211; pitch up indication<\/li><li>Turns through 270 deg &#8211; over-reads bank-angle &#8211; pitch up indication<\/li><li>Turns through 360 deg &#8211; correct bank-angle &#8211; correct indication<\/li><\/ul>\n\n\n\n<h3>Electrical Artificial Horizon<\/h3>\n\n\n\n<ul><li>Electrically driven artificial horizon uses electrical motor<\/li><li>The rotor rotates clockwise and is tied to gravity by two mercury switches<\/li><li>The switches correct for pitch and roll axis on base of rotor<\/li><li>Spin axis is retained vertical to the earth surface<\/li><li>Mercury switches are connected to torque motors<\/li><li>Switch for rolling plane is paired with torque motor on inner gimbal<\/li><li>Switch for pitching plane is paired with torque motor on outer gimbal<\/li><\/ul>\n\n\n\n<h3>Advantages of Electrical Artificial Horizon<\/h3>\n\n\n\n<ul><li>Electrically driven artificial horizon has some advantages<\/li><li>Powerful electric motor provides high spin rate<\/li><li>Artificial horizon has high rigidity and low precession<\/li><li>Instrument is more accurate and sticks more to earth reference<\/li><li>Fast erect system erects gyro at 120 deg per minute<\/li><li>Reduced acceleration and turn errors as compared to air driven gyro<\/li><li>Does not have a heavy erection chamber or pendulous vanes<\/li><\/ul>\n\n\n\n<h3>Errors of Electrical Artificial Horizon<\/h3>\n\n\n\n<ul><li>Errors are a result of inertia effect on mercury switch<\/li><li>Mercury switch falsely initiates precession of pitch torque motor<\/li><li>The error is corrected by use of a cut-off switch<\/li><li>Pitch cut-off activates on acceleration of 0.18 g<\/li><li>Roll cut-off activates at bank angle of 10 deg<\/li><\/ul>\n\n\n\n<h3>Remote Vertical Gyro<\/h3>\n\n\n\n<ul><li>Remote vertical gyro is also called as vertical axis data generation unit<\/li><li>Vertical gyro unit is located far away from flight deck in remote location<\/li><li>Remote gyro operates a synchro mechanism for multiple purposes<\/li><li>Vertical gyro unit is large and heavy with high spin rate due to powerful motor<\/li><li>Remote gyros have higher accuracy due to high rigidity and less precession<\/li><\/ul>\n\n\n\n<h3>Advantage of Remote Vertical Gyro<\/h3>\n\n\n\n<ul><li>Vertical gyro unit is large and heavy with high spin rate due to powerful motor<\/li><li>Remote gyros have higher accuracy due to high rigidity and less precession<\/li><li>One vertical gyro synchro system sends attitude signals to multiple systems<\/li><li>Steering computer and amplifier unit<\/li><li>Servo units within Attitude director indicator<\/li><li>Auto flight control system<\/li><\/ul>\n\n\n\n<h2>Share this Page<\/h2>\n","protected":false},"excerpt":{"rendered":"<p>Artificial Horizon Display of an Artificial Horizon Artificial horizon provides attitude of aircraft using a vertical axis gyro The gyro spin axis is maintained vertical to earth surface by gravity Gull wing etched on the outer glass moves with aircraft in pitch and roll The horizon image attached to an earth gyro maintains its orientation Nose up indication shows gull wing above the horizon Gull wing attached to outer gimbal moves down by a guide pin system Horizon bar attached to the inner gimbal retains its vertical position Artificial horizon&hellip;<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"disable_featured_image":false},"categories":[345],"tags":[],"_links":{"self":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/posts\/14486"}],"collection":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/comments?post=14486"}],"version-history":[{"count":0,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/posts\/14486\/revisions"}],"wp:attachment":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/media?parent=14486"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/categories?post=14486"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/tags?post=14486"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}