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DH8A on vectors to phl at 9000 ft experienced moderate to severe turbulence, descends below assigned altitude, after an ATC suggested heading to avoid WX.
| Attributes | |
| ACN | 641799 |
| Time | |
| Date | 200412 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : phl.airport |
| State Reference | PA |
| Altitude | msl single value : 9000 |
| Environment | |
| Flight Conditions | IMC |
| Weather Elements | Thunderstorm Rain Turbulence |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : phl.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | Dash 8-300 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : approach descent : intermediate altitude |
| Route In Use | arrival : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Experience | flight time last 90 days : 480 flight time total : 21000 flight time type : 15000 |
| ASRS Report | 641799 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : multi engine pilot : instrument pilot : commercial pilot : cfi |
| Experience | flight time last 90 days : 200 flight time total : 850 flight time type : 200 |
| ASRS Report | 641798 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : turbulence inflight encounter : weather non adherence : clearance |
| Independent Detector | other flight crewa other flight crewb |
| Resolutory Action | controller : issued new clearance controller : issued advisory |
| Supplementary | |
| Problem Areas | Weather Navigational Facility |
| Primary Problem | Weather |
Narrative:
We were on a vector of 320 degrees. (We asked for a 270 degree heading to get around a line of WX.) the controller said that it looked lighter on the 320 degree heading. I asked the controller for a heading to get around the WX. He said that he had traffic and indicated that he wanted us on that heading. On the back side of the rain, we encountered a strong downdraft and couldn't hold altitude. We dropped to 8500 ft before we could correct our descent. This lasted for approximately 2 mins. I told the controller that we couldn't maintain altitude due to moderate to severe turbulence. I don't understand why a facility like phl with doppler radar would send any airplanes through significant WX. I trusted his judgement when he described the WX in front of us as lighter. I will have to consider using emergency authority/authorized next time.
Original NASA ASRS Text
Title: DH8A ON VECTORS TO PHL AT 9000 FT EXPERIENCED MODERATE TO SEVERE TURB, DSNDS BELOW ASSIGNED ALT, AFTER AN ATC SUGGESTED HDG TO AVOID WX.
Narrative: WE WERE ON A VECTOR OF 320 DEGS. (WE ASKED FOR A 270 DEG HDG TO GET AROUND A LINE OF WX.) THE CTLR SAID THAT IT LOOKED LIGHTER ON THE 320 DEG HDG. I ASKED THE CTLR FOR A HDG TO GET AROUND THE WX. HE SAID THAT HE HAD TFC AND INDICATED THAT HE WANTED US ON THAT HDG. ON THE BACK SIDE OF THE RAIN, WE ENCOUNTERED A STRONG DOWNDRAFT AND COULDN'T HOLD ALT. WE DROPPED TO 8500 FT BEFORE WE COULD CORRECT OUR DSCNT. THIS LASTED FOR APPROX 2 MINS. I TOLD THE CTLR THAT WE COULDN'T MAINTAIN ALT DUE TO MODERATE TO SEVERE TURB. I DON'T UNDERSTAND WHY A FACILITY LIKE PHL WITH DOPPLER RADAR WOULD SEND ANY AIRPLANES THROUGH SIGNIFICANT WX. I TRUSTED HIS JUDGEMENT WHEN HE DESCRIBED THE WX IN FRONT OF US AS LIGHTER. I WILL HAVE TO CONSIDER USING EMER AUTH NEXT TIME.
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.