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DC9 flight crew descends past their cleared to altitude when they misunderstand the altitude in their clearance. ATC controller fails to catch their mistake during the readback hearback. Reporter cites static electrical interference.
| Attributes | |
| ACN | 380860 |
| Time | |
| Date | 199709 |
| Day | Tue |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : mem |
| State Reference | TN |
| Altitude | msl bound lower : 14000 msl bound upper : 16000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zme tower : atl |
| Operator | common carrier : air carrier |
| Make Model Name | DC-9 50 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent other |
| Route In Use | enroute : on vectors enroute other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 350 flight time total : 11500 flight time type : 350 |
| ASRS Report | 380860 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance none taken : detected after the fact other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
We were flight from phl to mem. Arrival sequence, cleared to cross on the mem 046 degrees 40 mi north at 10000 ft. Time AB20 am local. At AB35 am local, reclred to hold northeast on 046 degrees and 50 DME mem VOR, descend to 6000 ft. Clearance was read back as written. Descending through 14800 ft, center asked us our altitude. We responded 14800 ft. Then the controller reclred us to maintain 14000 ft. Controller advised us of original clearance of 16000 ft. We both copied 6000 ft and read back 6000 ft with no correction from controller. On original contact with this controller we complained of loud background noise and static on frequency. We believed this was due to thunderstorm in area.
Original NASA ASRS Text
Title: DC9 FLC DSNDS PAST THEIR CLRED TO ALT WHEN THEY MISUNDERSTAND THE ALT IN THEIR CLRNC. ATC CTLR FAILS TO CATCH THEIR MISTAKE DURING THE READBACK HEARBACK. RPTR CITES STATIC ELECTRICAL INTERFERENCE.
Narrative: WE WERE FLT FROM PHL TO MEM. ARR SEQUENCE, CLRED TO CROSS ON THE MEM 046 DEGS 40 MI N AT 10000 FT. TIME AB20 AM LCL. AT AB35 AM LCL, RECLRED TO HOLD NE ON 046 DEGS AND 50 DME MEM VOR, DSND TO 6000 FT. CLRNC WAS READ BACK AS WRITTEN. DSNDING THROUGH 14800 FT, CTR ASKED US OUR ALT. WE RESPONDED 14800 FT. THEN THE CTLR RECLRED US TO MAINTAIN 14000 FT. CTLR ADVISED US OF ORIGINAL CLRNC OF 16000 FT. WE BOTH COPIED 6000 FT AND READ BACK 6000 FT WITH NO CORRECTION FROM CTLR. ON ORIGINAL CONTACT WITH THIS CTLR WE COMPLAINED OF LOUD BACKGROUND NOISE AND STATIC ON FREQ. WE BELIEVED THIS WAS DUE TO TSTM IN AREA.
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.