Narrative:

We departed airport 'a' for an instrument competency check. I was acting as instrument instructor and safety pilot and therefore was the PNF. We contacted the tower at airport 'B' as we would be in and out of their class D airspace. I had the pilot put on his view limiting device and we proceeded outbound on a connecting radial from the VOR to intercept the DME arc which would take us directly to the final approach course for the ILS runway 22 at airport 'B' making several position reports to the tower as we proceeded. Since we were below radar coverage, I was monitoring the center frequency on the second radio. At some point prior to intercepting the ILS, I heard center clear a gulfstream gii for a visual approach. I was having a problem clearly hearing everything on both frequencys as the PF was keeping up a constant chatter about what he was doing, but I heard the gii cancel IFR. I did not hear his initial call to the tower. As we became established on the ILS, I called the tower, informing him of our position and asked him where the gii was. The tower replied that he was my 10 O'clock position on a left base for runway 22. After a short time I told the tower I had no contact with the gii. Once again they said he was 10 O'clock on base. As we reported the marker inbound I again called no contact and was told he was turning base to final at my 10 O'clock. As we proceeded inbound I became increasingly concerned about my failure to see the gii. When we were about 2 mi inside the marker, I was just ready to assume command and break off the approach to the right when the gii flashed by our right side, descending through our altitude at an estimated distance of less than 50 ft horizontal. Due to wake turbulence we then broke off the approach. I have searched my mind to try to determine what I should have done differently. The problem arose when the gii entered a descending base leg 10 or more mi from the airport. The tower's perspective due to size difference caused them to believe the gii was in front of us when in fact he was substantially behind us. The gii pilot was complacent since he thought he was in front of us due to the tower callouts. He did not see us until he was passing. We were beneath his wing and he was above and behind us precluding any chance of a visual contact. If I had turned right to avoid the unseen threat, I would have turned right into the gii. This area cries for radar coverage. While this tower has very recently been activated, the operators are very experienced. All participants are very thankful to be alive. Tower procedures should be reviewed to prevent future such occurrences.

Related reports:

Google
 

Original NASA ASRS Text

Title: NMAC OCCURRED WHEN A CPR GII PASSED A C206 TRAINING FLT ON FINAL APCH FOR THE SAME RWY. THE GII CAME FROM BEHIND THE CESSNA WHEN IT WAS THOUGHT TO BE ON A BASE LEG TURNING IN AHEAD OF IT BASED ON TFC INFO FROM THE LCL CTLR.

Narrative: WE DEPARTED ARPT 'A' FOR AN INST COMPETENCY CHK. I WAS ACTING AS INST INSTRUCTOR AND SAFETY PLT AND THEREFORE WAS THE PNF. WE CONTACTED THE TWR AT ARPT 'B' AS WE WOULD BE IN AND OUT OF THEIR CLASS D AIRSPACE. I HAD THE PLT PUT ON HIS VIEW LIMITING DEVICE AND WE PROCEEDED OUTBOUND ON A CONNECTING RADIAL FROM THE VOR TO INTERCEPT THE DME ARC WHICH WOULD TAKE US DIRECTLY TO THE FINAL APCH COURSE FOR THE ILS RWY 22 AT ARPT 'B' MAKING SEVERAL POS RPTS TO THE TWR AS WE PROCEEDED. SINCE WE WERE BELOW RADAR COVERAGE, I WAS MONITORING THE CTR FREQ ON THE SECOND RADIO. AT SOME POINT PRIOR TO INTERCEPTING THE ILS, I HEARD CTR CLR A GULFSTREAM GII FOR A VISUAL APCH. I WAS HAVING A PROB CLRLY HEARING EVERYTHING ON BOTH FREQS AS THE PF WAS KEEPING UP A CONSTANT CHATTER ABOUT WHAT HE WAS DOING, BUT I HEARD THE GII CANCEL IFR. I DID NOT HEAR HIS INITIAL CALL TO THE TWR. AS WE BECAME ESTABLISHED ON THE ILS, I CALLED THE TWR, INFORMING HIM OF OUR POS AND ASKED HIM WHERE THE GII WAS. THE TWR REPLIED THAT HE WAS MY 10 O'CLOCK POS ON A L BASE FOR RWY 22. AFTER A SHORT TIME I TOLD THE TWR I HAD NO CONTACT WITH THE GII. ONCE AGAIN THEY SAID HE WAS 10 O'CLOCK ON BASE. AS WE RPTED THE MARKER INBOUND I AGAIN CALLED NO CONTACT AND WAS TOLD HE WAS TURNING BASE TO FINAL AT MY 10 O'CLOCK. AS WE PROCEEDED INBOUND I BECAME INCREASINGLY CONCERNED ABOUT MY FAILURE TO SEE THE GII. WHEN WE WERE ABOUT 2 MI INSIDE THE MARKER, I WAS JUST READY TO ASSUME COMMAND AND BREAK OFF THE APCH TO THE R WHEN THE GII FLASHED BY OUR R SIDE, DSNDING THROUGH OUR ALT AT AN ESTIMATED DISTANCE OF LESS THAN 50 FT HORIZ. DUE TO WAKE TURB WE THEN BROKE OFF THE APCH. I HAVE SEARCHED MY MIND TO TRY TO DETERMINE WHAT I SHOULD HAVE DONE DIFFERENTLY. THE PROB AROSE WHEN THE GII ENTERED A DSNDING BASE LEG 10 OR MORE MI FROM THE ARPT. THE TWR'S PERSPECTIVE DUE TO SIZE DIFFERENCE CAUSED THEM TO BELIEVE THE GII WAS IN FRONT OF US WHEN IN FACT HE WAS SUBSTANTIALLY BEHIND US. THE GII PLT WAS COMPLACENT SINCE HE THOUGHT HE WAS IN FRONT OF US DUE TO THE TWR CALLOUTS. HE DID NOT SEE US UNTIL HE WAS PASSING. WE WERE BENEATH HIS WING AND HE WAS ABOVE AND BEHIND US PRECLUDING ANY CHANCE OF A VISUAL CONTACT. IF I HAD TURNED R TO AVOID THE UNSEEN THREAT, I WOULD HAVE TURNED RIGHT INTO THE GII. THIS AREA CRIES FOR RADAR COVERAGE. WHILE THIS TWR HAS VERY RECENTLY BEEN ACTIVATED, THE OPERATORS ARE VERY EXPERIENCED. ALL PARTICIPANTS ARE VERY THANKFUL TO BE ALIVE. TWR PROCS SHOULD BE REVIEWED TO PREVENT FUTURE SUCH OCCURRENCES.

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.