Narrative:

This flight involved my first actual experience with spatial disorientation and compromise of aircraft control; leading to significant altitude loss and deviation from our IFR clearance. What makes this exceptional is that I've been IFR qualified for almost 34 years; and have about 14;000 hours of IFR experience logged; including almost 800 hours of hard; actual instrument flight; (most of it during approaches under far part 121). I'm actively instructing instrument students in both aircraft and simulator and I regularly get into the sim to do my own full and partial panel proficiency training. In short: I'm not supposed to get disoriented and have control issues! (Yeah; I know that's a conceit. For decades I've been teaching pilots that no one's immune; and now I've proven the point personally.) our difficulties began shortly after takeoff. The student I'm instructing is finishing his instrument rating training; and we were intercepting the radial to execute the VOR approach. As we were proceeding at 2000 ft towards the VOR; approach began to query us about our heading. At this time both VOR's and the GPS showed us 'on course;' but there was a significant east wind and the student had let the heading drift to about 035 degrees. ATC kept asking about our heading and we were beginning to doubt our vacuum gyros. The student was beginning to fixate on the heading indicator; to the omission of the attitude indicator and turn coordinator. I issued corrective instruction; but the student was becoming more fixated and overloaded. We began to start losing altitude while experiencing heading control deviations; all the while ATC kept asking our heading. The student was beginning to significantly over control the aircraft; and could no longer respond fast enough to my instructions. Even though the vacuum annunciator light and gauge still indicated normal operation; we were suspecting the accuracy of the vacuum gyros; and the student asked if I had something to cover the ai. I covered the ai; (I never fly in IMC without something to isolate a malfunctioning or suspect instrument); and took control of the aircraft. I stabilized the aircraft; climbed back up to our assigned altitude; advised mcguire we were changing our destination to our home base; and requested a no-gyro vector to the VOR-a approach course. The aircraft has some instrument 'glitches.' the compass has significant deviation on some headings and is unlit; requiring the use of a flashlight to check heading. The heading indicator processes very quickly during any amount of maneuvering; and the attitude indicator is about 1-2 degrees off of true; in addition to being very slow to erect occasionally. I've long suspected this is probably not the best aircraft for flight in actual IMC; this event convinced me. I shot one approach to 200 ft above MDA; but even though we were in clear conditions under the ceiling; we were unable to locate the airport prior to the map. (The airport has pilot controlled lighting; but we were unable to see the field; so we weren't certain if the lighting was responding.) I went missed and asked for vectors back for another approach. (I had decided if the second approach didn't permit us to land that we would divert for an ILS at a controlled airport.) on the second VOR-a; I had the student attempt to bring the lights up. About one mile from the map; I finally could identify the REIL; and then see the runway lights and other identifying references. (The lights had probably been on since the first approach; but weren't visible due to the trees along the east side of the airport.) we circled to land; and contacted approach via phone to cancel on the ground. While this was an extremely valuable lesson for the student on the ugly reality of spatial disorientation; and what can lead to it. I'm still appalled at how easily I could get sucked into it. Once I took over at pilot flying; it became relatively easy to reestablish aircraft control although I didn'treally begin to believe our heading information until I incorporated the 'track' information from the GPS into the instrument scan to corroborate the gyro and compass readings. While none of the instrument 'glitches' were outright 'no go' items; this event did underscore how a number of light issues can merge to create more serious problems. The use of this aircraft involved a last minute equipment switch; and frankly; I had forgotten about some of the issues in the haste of the switch.

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Original NASA ASRS Text

Title: C172 instructor experienced spatial disorientation and compromise of aircraft control while training in IMC with a student at the controls. Control was regained by the instructor and the flight returned to home base with the Attitude Indicator covered.

Narrative: This flight involved my first actual experience with spatial disorientation and compromise of aircraft control; leading to significant altitude loss and deviation from our IFR clearance. What makes this exceptional is that I've been IFR qualified for almost 34 years; and have about 14;000 hours of IFR experience logged; including almost 800 hours of hard; actual instrument flight; (most of it during approaches under FAR part 121). I'm actively instructing instrument students in both aircraft and simulator and I regularly get into the sim to do my own full and partial panel proficiency training. In short: I'm not supposed to get disoriented and have control issues! (Yeah; I know that's a conceit. For decades I've been teaching pilots that no one's immune; and now I've proven the point personally.) Our difficulties began shortly after takeoff. The student I'm instructing is finishing his instrument rating training; and we were intercepting the radial to execute the VOR Approach. As we were proceeding at 2000 FT towards the VOR; Approach began to query us about our heading. At this time both VOR's and the GPS showed us 'on course;' but there was a significant East wind and the student had let the heading drift to about 035 degrees. ATC kept asking about our heading and we were beginning to doubt our vacuum gyros. The student was beginning to fixate on the heading indicator; to the omission of the Attitude Indicator and Turn Coordinator. I issued corrective instruction; but the student was becoming more fixated and overloaded. We began to start losing altitude while experiencing heading control deviations; all the while ATC kept asking our heading. The student was beginning to significantly over control the aircraft; and could no longer respond fast enough to my instructions. Even though the vacuum annunciator light and gauge still indicated normal operation; we were suspecting the accuracy of the vacuum gyros; and the student asked if I had something to cover the AI. I covered the AI; (I never fly in IMC without something to isolate a malfunctioning or suspect instrument); and took control of the aircraft. I stabilized the aircraft; climbed back up to our assigned altitude; advised McGuire we were changing our destination to our home base; and requested a no-gyro vector to the VOR-A approach course. The aircraft has some instrument 'glitches.' The compass has significant deviation on some headings and is unlit; requiring the use of a flashlight to check heading. The Heading Indicator processes very quickly during any amount of maneuvering; and the Attitude Indicator is about 1-2 degrees off of true; in addition to being very slow to erect occasionally. I've long suspected this is probably not the best aircraft for flight in actual IMC; this event convinced me. I shot one approach to 200 FT above MDA; but even though we were in clear conditions under the ceiling; we were unable to locate the airport prior to the MAP. (The airport has pilot controlled lighting; but we were unable to see the field; so we weren't certain if the lighting was responding.) I went missed and asked for vectors back for another approach. (I had decided if the second approach didn't permit us to land that we would divert for an ILS at a controlled airport.) On the second VOR-A; I had the student attempt to bring the lights up. About one mile from the MAP; I finally could identify the REIL; and then see the runway lights and other identifying references. (The lights had probably been on since the first approach; but weren't visible due to the trees along the East side of the airport.) We circled to land; and contacted Approach via phone to cancel on the ground. While this was an extremely valuable lesson for the student on the ugly reality of spatial disorientation; and what can lead to it. I'm still appalled at how easily I could get sucked into it. Once I took over at pilot flying; it became relatively easy to reestablish aircraft control although I didn'treally begin to believe our heading information until I incorporated the 'track' information from the GPS into the instrument scan to corroborate the gyro and compass readings. While none of the instrument 'glitches' were outright 'no go' items; this event did underscore how a number of light issues can merge to create more serious problems. The use of this aircraft involved a last minute equipment switch; and frankly; I had forgotten about some of the issues in the haste of the switch.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.