 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
WX interference and frequency congestion resulted in the flight crew having to declare an emergency to descend and escape severe turbulence while unable to gain a clearance from ATC.
| Attributes | |
| ACN | 334747 |
| Time | |
| Date | 199604 |
| Day | Sun |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | atc facility : mrb |
| State Reference | WV |
| Altitude | msl bound lower : 37000 msl bound upper : 37000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Dawn |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | cruise 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 : 100 flight time total : 16000 flight time type : 800 |
| ASRS Report | 334747 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : flight engineer pilot : commercial pilot : atp pilot : cfi |
| Experience | flight time last 90 days : 100 flight time total : 7000 flight time type : 200 |
| ASRS Report | 334897 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : weather |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : declared emergency flight crew : took evasive action flight crew : exited adverse environment |
| Consequence | Other |
Narrative:
A very large WX system had tops above FL390 for 200 mi. St elmos was very heavy and radio communication was poor. Turbulence was light/occasional moderate. Radio frequency 128.77 (I think) was crowded and controller transmission was 2 X 2. We came out of the clouds into clear air and began requesting lower altitude. We were unable to reach ATC and could not get a relay from other aircraft. We then encountered 3 consecutive mountain waves followed by moderate to occasionally severe turbulence. We squawked 7700 and began descent, then changed to 7600. The first officer found iad ATC and we resumed a normal profile.
Original NASA ASRS Text
Title: WX INTERFERENCE AND FREQ CONGESTION RESULTED IN THE FLC HAVING TO DECLARE AN EMER TO DSND AND ESCAPE SEVERE TURB WHILE UNABLE TO GAIN A CLRNC FROM ATC.
Narrative: A VERY LARGE WX SYS HAD TOPS ABOVE FL390 FOR 200 MI. ST ELMOS WAS VERY HVY AND RADIO COM WAS POOR. TURB WAS LIGHT/OCCASIONAL MODERATE. RADIO FREQ 128.77 (I THINK) WAS CROWDED AND CTLR XMISSION WAS 2 X 2. WE CAME OUT OF THE CLOUDS INTO CLR AIR AND BEGAN REQUESTING LOWER ALT. WE WERE UNABLE TO REACH ATC AND COULD NOT GET A RELAY FROM OTHER ACFT. WE THEN ENCOUNTERED 3 CONSECUTIVE MOUNTAIN WAVES FOLLOWED BY MODERATE TO OCCASIONALLY SEVERE TURB. WE SQUAWKED 7700 AND BEGAN DSCNT, THEN CHANGED TO 7600. THE FO FOUND IAD ATC AND WE RESUMED A NORMAL PROFILE.
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.