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Military pilot took descent clearance of another aircraft which resulted in less than standard separation.
| Attributes | |
| ACN | 146074 |
| Time | |
| Date | 199005 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : vhp |
| State Reference | IN |
| Altitude | msl bound lower : 26500 msl bound upper : 28000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zid tower : ord |
| Operator | other |
| Make Model Name | Fighter |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 8 |
| ASRS Report | 146074 |
| Person 2 | |
| Affiliation | government : military |
| Function | flight crew : single pilot |
| Qualification | pilot : military |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : required legal separation other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Miss Distance | horizontal : 9000 |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Traffic was moderate but complex. Fgt was handed off about 40 mi south of vhp at FL350. Fgt had to be low level by 25 north of vhp. Numerous traffic complicated fgt's descent. Hilltop MOA which overlies the fgt VFR entry point was active at the time, 10000'-FL340. Fgt was descended to FL310 so as to be level in 2 mins and turned right heading 360 degrees. Mdt was handed off at FL270 on radar vector 050 degrees. Shortly afterward, mdt was turned right heading 090 degrees to avoid hilltop. After verifying fgt's altitude of FL310, further clearance was issued to FL280. Fgt's readback was correct. Medium large transport checked in at FL310. Fgt was issued traffic on mdt at 10 O'clock, 5MI, eastbound at FL270. After waiting 2 seconds for a response, I issued descent clearance to medium large transport to FL240, 1800' rate of descent per min. After I unkeyed, I heard the words 'fgt,' then medium large transport transmitted his readback. The VHF was louder than the UHF. I heard. As did my d-man, the readback of medium large transport, but fgt was blocked out. I then gave 3 other control instructions to other aircraft. I assumed fgt was acknowledging the traffic. In essence, fgt took medium large transport's descent clearance. I returned to fgt only to notice passing 26500'. I issued traffic and had him continue descent. Fgt call sign (wind commander) sounds a lot like medium large transport call sign, doesn't it?
Original NASA ASRS Text
Title: MIL PLT TOOK DESCENT CLRNC OF ANOTHER ACFT WHICH RESULTED IN LESS THAN STANDARD SEPARATION.
Narrative: TFC WAS MODERATE BUT COMPLEX. FGT WAS HANDED OFF ABOUT 40 MI S OF VHP AT FL350. FGT HAD TO BE LOW LEVEL BY 25 N OF VHP. NUMEROUS TFC COMPLICATED FGT'S DSNT. HILLTOP MOA WHICH OVERLIES THE FGT VFR ENTRY POINT WAS ACTIVE AT THE TIME, 10000'-FL340. FGT WAS DSNDED TO FL310 SO AS TO BE LEVEL IN 2 MINS AND TURNED RIGHT HDG 360 DEGS. MDT WAS HANDED OFF AT FL270 ON RADAR VECTOR 050 DEGS. SHORTLY AFTERWARD, MDT WAS TURNED RIGHT HDG 090 DEGS TO AVOID HILLTOP. AFTER VERIFYING FGT'S ALT OF FL310, FURTHER CLRNC WAS ISSUED TO FL280. FGT'S READBACK WAS CORRECT. MLG CHKED IN AT FL310. FGT WAS ISSUED TFC ON MDT AT 10 O'CLOCK, 5MI, EBND AT FL270. AFTER WAITING 2 SECS FOR A RESPONSE, I ISSUED DSNT CLRNC TO MLG TO FL240, 1800' RATE OF DSNT PER MIN. AFTER I UNKEYED, I HEARD THE WORDS 'FGT,' THEN MLG XMITTED HIS READBACK. THE VHF WAS LOUDER THAN THE UHF. I HEARD. AS DID MY D-MAN, THE READBACK OF MLG, BUT FGT WAS BLOCKED OUT. I THEN GAVE 3 OTHER CTL INSTRUCTIONS TO OTHER ACFT. I ASSUMED FGT WAS ACKNOWLEDGING THE TFC. IN ESSENCE, FGT TOOK MLG'S DSNT CLRNC. I RETURNED TO FGT ONLY TO NOTICE PASSING 26500'. I ISSUED TFC AND HAD HIM CONTINUE DSNT. FGT CALL SIGN (WIND COMMANDER) SOUNDS A LOT LIKE MLG CALL SIGN, DOESN'T IT?
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.