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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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ZZZ controller described loss of separation when LR35 experienced aircraft pressure emergency and descended through occupied altitude.
| Attributes | |
| ACN | 766308 |
| Time | |
| Date | 200712 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | msl single value : 37000 |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zzz.artcc tower : hnl.tower |
| Operator | common carrier : air carrier |
| Make Model Name | Learjet 35 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | cruise : level cruise : enroute altitude change |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zzz.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller limited radar : 23 controller non radar : 23 controller radar : 23 |
| ASRS Report | 766308 |
| Person 2 | |
| Affiliation | company : corporate |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : required legal separation other anomaly other |
| Independent Detector | atc equipment : conflict alert other controllera |
| Resolutory Action | controller : issued new clearance flight crew : took evasive action flight crew : declared emergency |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
An LR35; started a rapid descent from 43000 ft and started squawking 'emrg.' aircraft was directly below the lear at 38000 ft. I turned aircraft Y runway xxr and descended them to 37000 ft. I was unable to communicate with the lear until they were through 36000 ft. Once communication was established the lear advised he had lost pressurization and needed to keep descending. I cleared the lear to 24000 ft followed shortly by a descent to 11000 ft. I changed the lear to another controller's frequency and cleared aircraft Y back on course. The 2 targets were merged through the entire incident; and as far as I know; TCAS was never activated. The conflict alert was activated with the closest proximity of 2.6 mi and 100 ft.
Original NASA ASRS Text
Title: ZZZ CTLR DESCRIBED LOSS OF SEPARATION WHEN LR35 EXPERIENCED ACFT PRESSURE EMER AND DESCENDED THROUGH OCCUPIED ALT.
Narrative: AN LR35; STARTED A RAPID DSCNT FROM 43000 FT AND STARTED SQUAWKING 'EMRG.' ACFT WAS DIRECTLY BELOW THE LEAR AT 38000 FT. I TURNED ACFT Y RWY XXR AND DSNDED THEM TO 37000 FT. I WAS UNABLE TO COMMUNICATE WITH THE LEAR UNTIL THEY WERE THROUGH 36000 FT. ONCE COM WAS ESTABLISHED THE LEAR ADVISED HE HAD LOST PRESSURIZATION AND NEEDED TO KEEP DSNDING. I CLRED THE LEAR TO 24000 FT FOLLOWED SHORTLY BY A DSCNT TO 11000 FT. I CHANGED THE LEAR TO ANOTHER CTLR'S FREQ AND CLRED ACFT Y BACK ON COURSE. THE 2 TARGETS WERE MERGED THROUGH THE ENTIRE INCIDENT; AND AS FAR AS I KNOW; TCAS WAS NEVER ACTIVATED. THE CONFLICT ALERT WAS ACTIVATED WITH THE CLOSEST PROX OF 2.6 MI AND 100 FT.
Data retrieved from NASA's ASRS site as of January 2009 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.