Narrative:

I was cleared for immediate departure from teb. I pulled onto runway 1, and went through the final checklist ('tits': time, INS, transponder, strobe). When checking the dg, with the compass and runway heading, I noticed it was 20 degrees off and made a mental note to keep track of precession. Precession had been noted on the inbound flight. After passing through about 500', I was told to contact departure. I acknowledged and hit the FLIP-flop button on the #1 communication and called. I got no response so I tuned the #2 communication to departure to try again. In my small aircraft the radios are located beneath the yokes, with the #2 on the bottom. This requires a large movement of the head in 2 axes. When I raised my head I noted the attitude indicator was way off to the right and I started to follow it. It became clear almost immediately that something was wrong, as the airspeed was building and the rate-of-climb was descending. I caught a glimpse of the approaching ground before I got back under control with the turn-and-bank and started to resume climb. The dg was turning at this point and the ai was tilted to the right. I simultaneously called departure and declared a no gyro emergency. The time elapsed from tuning the radio until stabilization was only a few seconds, although it seemed like eternity. Because the aft had not been close to stabilized, the compass reading was ambiguous, but I realized that I was significantly off my correct heading. The controllers acted with aplomb and reassurance and a successful no gyro ILS was accomplished. What happened? The ai had a leak in the case (discovered by the INS shop the next week), causing it to slow down and tilt and the dg to precess. The rapid head movement of retuning the radio caused vertigo and I started to follow the tumbling ai INS xchk located the defective gyros in time to prevent disaster, partial panel ability with excellent assistance from ATC assured a successful landing. How to prevent similar occurrences? Personally, I had raised my personal minimums for INS takeoff in controled airspace. I would also support the FAA in requiring redundant, or instantaneous vacuum backup systems for part 91 operators in TCA's and arsa's who takeoff with low IFR conditions. I am also going to have a backup system added to the viking. Human performance? It had been a long and tiring day, but the WX at my destination was for VFR with good visibility. I would not have launched if the approach at west 10 was IFR. In fact, in 10/89, I stayed in teb overnight when a night departure would have led to a low IFR approach. It has been my experience that the safety criteria of each decision is balanced by other factors. Hence the need for a personal set of rigid minimum (maximum) criteria that cannot be altered by current factors unrelated to safety. My minimums just went up!

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Original NASA ASRS Text

Title: PLT DEPARTING TEB AT NIGHT IN IMC EXPERIENCES VERTIGO AND DISORIENTATION DUE TO LOWERING HEAD TO CHANGE RADIO FREQS, AND SIMULTANEOUS FAILURE OF ATTITUDE INDICATOR DUE TO VACUUM LEAK.

Narrative: I WAS CLRED FOR IMMEDIATE DEP FROM TEB. I PULLED ONTO RWY 1, AND WENT THROUGH THE FINAL CHKLIST ('TITS': TIME, INS, XPONDER, STROBE). WHEN CHKING THE DG, WITH THE COMPASS AND RWY HDG, I NOTICED IT WAS 20 DEGS OFF AND MADE A MENTAL NOTE TO KEEP TRACK OF PRECESSION. PRECESSION HAD BEEN NOTED ON THE INBND FLT. AFTER PASSING THROUGH ABOUT 500', I WAS TOLD TO CONTACT DEP. I ACKNOWLEDGED AND HIT THE FLIP-FLOP BUTTON ON THE #1 COM AND CALLED. I GOT NO RESPONSE SO I TUNED THE #2 COM TO DEP TO TRY AGAIN. IN MY SMA THE RADIOS ARE LOCATED BENEATH THE YOKES, WITH THE #2 ON THE BOTTOM. THIS REQUIRES A LARGE MOVEMENT OF THE HEAD IN 2 AXES. WHEN I RAISED MY HEAD I NOTED THE ATTITUDE INDICATOR WAS WAY OFF TO THE RIGHT AND I STARTED TO FOLLOW IT. IT BECAME CLEAR ALMOST IMMEDIATELY THAT SOMETHING WAS WRONG, AS THE AIRSPD WAS BUILDING AND THE RATE-OF-CLIMB WAS DSNDING. I CAUGHT A GLIMPSE OF THE APCHING GND BEFORE I GOT BACK UNDER CONTROL WITH THE TURN-AND-BANK AND STARTED TO RESUME CLB. THE DG WAS TURNING AT THIS POINT AND THE AI WAS TILTED TO THE RIGHT. I SIMULTANEOUSLY CALLED DEP AND DECLARED A NO GYRO EMER. THE TIME ELAPSED FROM TUNING THE RADIO UNTIL STABILIZATION WAS ONLY A FEW SECS, ALTHOUGH IT SEEMED LIKE ETERNITY. BECAUSE THE AFT HAD NOT BEEN CLOSE TO STABILIZED, THE COMPASS READING WAS AMBIGUOUS, BUT I REALIZED THAT I WAS SIGNIFICANTLY OFF MY CORRECT HDG. THE CTLRS ACTED WITH APLOMB AND REASSURANCE AND A SUCCESSFUL NO GYRO ILS WAS ACCOMPLISHED. WHAT HAPPENED? THE AI HAD A LEAK IN THE CASE (DISCOVERED BY THE INS SHOP THE NEXT WK), CAUSING IT TO SLOW DOWN AND TILT AND THE DG TO PRECESS. THE RAPID HEAD MOVEMENT OF RETUNING THE RADIO CAUSED VERTIGO AND I STARTED TO FOLLOW THE TUMBLING AI INS XCHK LOCATED THE DEFECTIVE GYROS IN TIME TO PREVENT DISASTER, PARTIAL PANEL ABILITY WITH EXCELLENT ASSISTANCE FROM ATC ASSURED A SUCCESSFUL LNDG. HOW TO PREVENT SIMILAR OCCURRENCES? PERSONALLY, I HAD RAISED MY PERSONAL MINIMUMS FOR INS TKOF IN CTLED AIRSPACE. I WOULD ALSO SUPPORT THE FAA IN REQUIRING REDUNDANT, OR INSTANTANEOUS VACUUM BACKUP SYSTEMS FOR PART 91 OPERATORS IN TCA'S AND ARSA'S WHO TKOF WITH LOW IFR CONDITIONS. I AM ALSO GOING TO HAVE A BACKUP SYS ADDED TO THE VIKING. HUMAN PERFORMANCE? IT HAD BEEN A LONG AND TIRING DAY, BUT THE WX AT MY DEST WAS FOR VFR WITH GOOD VISIBILITY. I WOULD NOT HAVE LAUNCHED IF THE APCH AT W 10 WAS IFR. IN FACT, IN 10/89, I STAYED IN TEB OVERNIGHT WHEN A NIGHT DEP WOULD HAVE LED TO A LOW IFR APCH. IT HAS BEEN MY EXPERIENCE THAT THE SAFETY CRITERIA OF EACH DECISION IS BALANCED BY OTHER FACTORS. HENCE THE NEED FOR A PERSONAL SET OF RIGID MINIMUM (MAX) CRITERIA THAT CANNOT BE ALTERED BY CURRENT FACTORS UNRELATED TO SAFETY. MY MINIMUMS JUST WENT UP!

Data retrieved from NASA's ASRS site as of July 2007 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.