Narrative:

After departing boulder city airport, mr X (the check airman, on the second flight it was mr Y) reached up and turned off the transponder and said 'we don't use these, no one can see us here anyway.' he was the owner/boss so I went along with what he said. After checking later, I found that we were under the TCA and within the mode C ring, also during unusual attitude recovery he put the aircraft in a bank altitude in excess of 90 degree bank. A condition which I thought was excessive, especially without parachutes. I feel that flying around with the transponder off created a potential hazard because we would have been invisible to an aircraft equipped with 'TCASII.' to conduct flts over the grand canyon without this equipment turned on is an operating procedure that should probably be changed.

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Original NASA ASRS Text

Title: CHK PLT ON TRAINING FLT TURNED OFF THE TRANSPONDER WITHIN 30 MI VEIL OF TCA.

Narrative: AFTER DEPARTING BOULDER CITY ARPT, MR X (THE CHK AIRMAN, ON THE SECOND FLT IT WAS MR Y) REACHED UP AND TURNED OFF THE TRANSPONDER AND SAID 'WE DON'T USE THESE, NO ONE CAN SEE US HERE ANYWAY.' HE WAS THE OWNER/BOSS SO I WENT ALONG WITH WHAT HE SAID. AFTER CHKING LATER, I FOUND THAT WE WERE UNDER THE TCA AND WITHIN THE MODE C RING, ALSO DURING UNUSUAL ATTITUDE RECOVERY HE PUT THE ACFT IN A BANK ALT IN EXCESS OF 90 DEG BANK. A CONDITION WHICH I THOUGHT WAS EXCESSIVE, ESPECIALLY WITHOUT PARACHUTES. I FEEL THAT FLYING AROUND WITH THE TRANSPONDER OFF CREATED A POTENTIAL HAZARD BECAUSE WE WOULD HAVE BEEN INVISIBLE TO AN ACFT EQUIPPED WITH 'TCASII.' TO CONDUCT FLTS OVER THE GRAND CANYON WITHOUT THIS EQUIP TURNED ON IS AN OPERATING PROC THAT SHOULD PROBABLY BE CHANGED.

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.