Narrative:

Violated R2501 airspace. Was returning from formation clinic at igm. Was flying wing in flight of 2. Had agreed with lead that 10 mi southeast of the tnp VOR I would leave element to head to home airport (I7A) and lead would head home to san diego. Had previously determined heading from break-up point B I7A would keep me south of R2501. As agreed, broke with lead 10 mi southeast of tnp and turned to 270 degrees, the heading operations showed for I7A. Called ZLA for advisories and input transponder code. Center could not find me, and had me recycle transponder. This went on for 5 mins until center said since he could not see me he could not provide service. Meanwhile, something did not feel right with navigation, terrain looked unfamiliar. CDI for HSI would not stay centered (GPS was coupled to HSI). GPS/HSI was commanding massive course corrections, xchking with vors suggested I was way off course. The setting sun and haze made it impossible to see the 2 large landmarks in the area (mt san gorgonio and mt san jacinto). It finally dawned on me to xchk the HSI to the compass. The HSI was 50-60 degrees off to the south. (I had checked compass and HSI on the ground before takeoff and they aligned.) the HSI error resulted in me turning to a true heading of 320-330 degrees even though 270 degrees was indicated. This took me into the restr airspace. At almost 4 mi per min it does not take long to get pretty far off course. I think when I made my 60 degree break, it precessed the HSI. Since I had been flying wing, I had not been calibrating my navigation, so I had no reference except the HSI. I did a pretty good job of planning to stay out of R2501, and would have used ZLA as back-up, but the combination of HSI error, ZLA not seeing me, low sun obscuring known landmarked conspired to put me in R2501. Clearly, had I crosschecked the HSI to the company sooner, I might have stayed out. This was a tough one because in normal circumstances I would have noticed navigation instrument problems early on, but since I was flying formation, I was not even navigating. The only thing I can think of to avoid this situation in the future is to check the HSI against the compass sooner.

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Original NASA ASRS Text

Title: T28 PLT ACCIDENTALLY ENTERED RESTR AIRSPACE AFTER HAVING HIS DIRECTIONAL GYRO TUMBLE.

Narrative: VIOLATED R2501 AIRSPACE. WAS RETURNING FROM FORMATION CLINIC AT IGM. WAS FLYING WING IN FLT OF 2. HAD AGREED WITH LEAD THAT 10 MI SE OF THE TNP VOR I WOULD LEAVE ELEMENT TO HEAD TO HOME ARPT (I7A) AND LEAD WOULD HEAD HOME TO SAN DIEGO. HAD PREVIOUSLY DETERMINED HDG FROM BREAK-UP POINT B I7A WOULD KEEP ME S OF R2501. AS AGREED, BROKE WITH LEAD 10 MI SE OF TNP AND TURNED TO 270 DEGS, THE HDG OPS SHOWED FOR I7A. CALLED ZLA FOR ADVISORIES AND INPUT XPONDER CODE. CTR COULD NOT FIND ME, AND HAD ME RECYCLE XPONDER. THIS WENT ON FOR 5 MINS UNTIL CTR SAID SINCE HE COULD NOT SEE ME HE COULD NOT PROVIDE SVC. MEANWHILE, SOMETHING DID NOT FEEL RIGHT WITH NAV, TERRAIN LOOKED UNFAMILIAR. CDI FOR HSI WOULD NOT STAY CTRED (GPS WAS COUPLED TO HSI). GPS/HSI WAS COMMANDING MASSIVE COURSE CORRECTIONS, XCHKING WITH VORS SUGGESTED I WAS WAY OFF COURSE. THE SETTING SUN AND HAZE MADE IT IMPOSSIBLE TO SEE THE 2 LARGE LANDMARKS IN THE AREA (MT SAN GORGONIO AND MT SAN JACINTO). IT FINALLY DAWNED ON ME TO XCHK THE HSI TO THE COMPASS. THE HSI WAS 50-60 DEGS OFF TO THE S. (I HAD CHKED COMPASS AND HSI ON THE GND BEFORE TKOF AND THEY ALIGNED.) THE HSI ERROR RESULTED IN ME TURNING TO A TRUE HDG OF 320-330 DEGS EVEN THOUGH 270 DEGS WAS INDICATED. THIS TOOK ME INTO THE RESTR AIRSPACE. AT ALMOST 4 MI PER MIN IT DOES NOT TAKE LONG TO GET PRETTY FAR OFF COURSE. I THINK WHEN I MADE MY 60 DEG BREAK, IT PRECESSED THE HSI. SINCE I HAD BEEN FLYING WING, I HAD NOT BEEN CALIBRATING MY NAV, SO I HAD NO REF EXCEPT THE HSI. I DID A PRETTY GOOD JOB OF PLANNING TO STAY OUT OF R2501, AND WOULD HAVE USED ZLA AS BACK-UP, BUT THE COMBINATION OF HSI ERROR, ZLA NOT SEEING ME, LOW SUN OBSCURING KNOWN LANDMARKED CONSPIRED TO PUT ME IN R2501. CLRLY, HAD I XCHKED THE HSI TO THE COMPANY SOONER, I MIGHT HAVE STAYED OUT. THIS WAS A TOUGH ONE BECAUSE IN NORMAL CIRCUMSTANCES I WOULD HAVE NOTICED NAV INST PROBS EARLY ON, BUT SINCE I WAS FLYING FORMATION, I WAS NOT EVEN NAVING. THE ONLY THING I CAN THINK OF TO AVOID THIS SIT IN THE FUTURE IS TO CHK THE HSI AGAINST THE COMPASS SOONER.

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.