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Altitude deviation altitude excursion by PIC of air carrier widebody transport after receiving 2 fluctuations from low level radar altimeter #1 and a pull up command from the ground proximity warning system.
| Attributes | |
| ACN | 184521 |
| Time | |
| Date | 199107 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : huo |
| State Reference | NY |
| Altitude | msl bound lower : 5000 msl bound upper : 6000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : n90 |
| Operator | common carrier : air carrier |
| Make Model Name | Widebody, Low Wing, 4 Turbojet Eng |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 240 flight time total : 24000 flight time type : 3000 |
| ASRS Report | 184521 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : flight engineer |
| Experience | flight time last 90 days : 220 flight time total : 12000 flight time type : 1000 |
| ASRS Report | 184705 |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified |
| Resolutory Action | controller : issued new clearance flight crew : exited adverse environment flight crew : took evasive action |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
While deviating around trw's line at approximately xy:45 Z in light to moderate rain showers at INS approximately position 4133. On 07542.iw at 5000 ft, indicating 250 IAS on a 220 degree radar heading. The captain's llra suddenly indicated, and was called out 1500 ft 2 times while the first officer's did not indicate. The captain/crew commented briefly 'it might be another aircraft,' as several were also deviating around trws. WX, lightning, and light hail. 1 min later the ground proximity 'pull up' lit/sounded, and the captain's llra again showed 1500 ft decreasing. An immediate pull up/climb was initiated to 6000 ft, with immediate ATC center notification and clearance to 6000 ft. The ground proximity warning terminated. The first officer llra never indicated. ATC was advised of suspicion of conflicting traffic and said 'he had no aircraft in the area on radar.' the llra and ground proximity warning were written up in maintenance log. Contributing factors: WX deviations around trws. Irregular rtings. Ama awareness. Changing terrain. Turbulence/icing/lightning.
Original NASA ASRS Text
Title: ALT DEV ALT EXCURSION BY PIC OF ACR WDB AFTER RECEIVING 2 FLUCTUATIONS FROM LOW LEVEL RADAR ALTIMETER #1 AND A PULL UP COMMAND FROM THE GND PROX WARNING SYS.
Narrative: WHILE DEVIATING AROUND TRW'S LINE AT APPROX XY:45 Z IN LIGHT TO MODERATE RAIN SHOWERS AT INS APPROX POS 4133. ON 07542.IW AT 5000 FT, INDICATING 250 IAS ON A 220 DEG RADAR HDG. THE CAPT'S LLRA SUDDENLY INDICATED, AND WAS CALLED OUT 1500 FT 2 TIMES WHILE THE FO'S DID NOT INDICATE. THE CAPT/CREW COMMENTED BRIEFLY 'IT MIGHT BE ANOTHER ACFT,' AS SEVERAL WERE ALSO DEVIATING AROUND TRWS. WX, LIGHTNING, AND LIGHT HAIL. 1 MIN LATER THE GND PROX 'PULL UP' LIT/SOUNDED, AND THE CAPT'S LLRA AGAIN SHOWED 1500 FT DECREASING. AN IMMEDIATE PULL UP/CLB WAS INITIATED TO 6000 FT, WITH IMMEDIATE ATC CENTER NOTIFICATION AND CLRNC TO 6000 FT. THE GND PROX WARNING TERMINATED. THE FO LLRA NEVER INDICATED. ATC WAS ADVISED OF SUSPICION OF CONFLICTING TFC AND SAID 'HE HAD NO ACFT IN THE AREA ON RADAR.' THE LLRA AND GND PROX WARNING WERE WRITTEN UP IN MAINT LOG. CONTRIBUTING FACTORS: WX DEVS AROUND TRWS. IRREGULAR RTINGS. AMA AWARENESS. CHANGING TERRAIN. TURB/ICING/LIGHTNING.
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.