Narrative:

My problem was caused by an small aircraft that had declared a medical emergency while on approach to sna airport on dec/xx/93 at approximately XA45Z. The pilot of the small aircraft was unable to maintain his assigned altitude of 3000 ft MSL coast approach had assigned him. The small aircraft pilot was not able to determine his altitude because his passenger had vomited across his instrument panel. Coast approach noticed the small aircraft mode C readout to be 3600 ft. The controller called the small aircraft and asked him to verify his altitude. He responded that he was at 2700 ft and would climb back to 3000 ft. Coast approach continued to confirm that small aircraft should maintain 3000 ft. By now, I was receiving a TCASII RA of climb, climb, climb. I immediately started to climb. At 4200 ft the RA stopped. Now I was able to notify coast approach of my altitude deviation, whereas before there was too much radio communication between coast approach and the small aircraft. I had to leave my assigned altitude of 4000 ft for approximately 5-7 seconds. I feel that the controller should have changed my course and/or altitude once he saw that small aircraft was having problems determining his correct altitude.

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Original NASA ASRS Text

Title: SMA UNABLE TO MAINTAIN ALT ACCOUNT INST OBSCURED. LGT DEVIATED ALT ACCOUNT TCASII RA.

Narrative: MY PROB WAS CAUSED BY AN SMA THAT HAD DECLARED A MEDICAL EMER WHILE ON APCH TO SNA ARPT ON DEC/XX/93 AT APPROX XA45Z. THE PLT OF THE SMA WAS UNABLE TO MAINTAIN HIS ASSIGNED ALT OF 3000 FT MSL COAST APCH HAD ASSIGNED HIM. THE SMA PLT WAS NOT ABLE TO DETERMINE HIS ALT BECAUSE HIS PAX HAD VOMITED ACROSS HIS INST PANEL. COAST APCH NOTICED THE SMA MODE C READOUT TO BE 3600 FT. THE CTLR CALLED THE SMA AND ASKED HIM TO VERIFY HIS ALT. HE RESPONDED THAT HE WAS AT 2700 FT AND WOULD CLB BACK TO 3000 FT. COAST APCH CONTINUED TO CONFIRM THAT SMA SHOULD MAINTAIN 3000 FT. BY NOW, I WAS RECEIVING A TCASII RA OF CLB, CLB, CLB. I IMMEDIATELY STARTED TO CLB. AT 4200 FT THE RA STOPPED. NOW I WAS ABLE TO NOTIFY COAST APCH OF MY ALTDEV, WHEREAS BEFORE THERE WAS TOO MUCH RADIO COM BTWN COAST APCH AND THE SMA. I HAD TO LEAVE MY ASSIGNED ALT OF 4000 FT FOR APPROX 5-7 SECONDS. I FEEL THAT THE CTLR SHOULD HAVE CHANGED MY COURSE AND/OR ALT ONCE HE SAW THAT SMA WAS HAVING PROBS DETERMINING HIS CORRECT ALT.

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.