CL604 flight crew encounters severe turbulence during cruise.

Attributes
ACN	553327
Time
Date	200207
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : zfw.artcc
State Reference	TX
Altitude	msl bound lower : 36000 msl bound upper : 38200
Environment
Flight Conditions	IMC
Weather Elements	Thunderstorm Turbulence other
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw.artcc
Operator	general aviation : corporate
Make Model Name	Challenger CL604
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	cruise : level
Route In Use	enroute airway : j29.airway
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 300 flight time total : 7500 flight time type : 1200
ASRS Report	553327
Person 2
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 3700 flight time type : 1500
ASRS Report	553324
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude inflight encounter : turbulence inflight encounter : weather
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : took precautionary avoidance action flight crew : exited adverse environment
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Weather Flight Crew Human Performance Environmental Factor Aircraft
Primary Problem	Aircraft

Narrative:

Prior to departure, the captain and I discussed a possible radar issue where the aircraft was having difficulty depicting WX. On the ground, we were able to depict a cell off the end of runway 15L, which was the departure runway. After departure, we noted that the radar was not depicting precipitation and we visually circumnaved several isolated thunderstorms. While on J29, we entered into a high altitude haze layer and shortly thereafter I noted a large thunderstorm directly in front of us and promptly noted it to the PF. Since our visibility was very low and we had very little time to react, the captain hit the sync button and made a hard right turn for WX avoidance. We entered the cell as its smallest point through well above our cruise attitude. We immediately experienced severe turbulence and heavy rain yet at no point was WX depicted on the radar. As a result of the turbulence, we climbed as high as FL382 and descended as low as FL360. ATC noted the altitude deviation and I briefly told him what happened. In my opinion, this incident was strictly because of a bad radar system in the aircraft.

Original NASA ASRS Text

Title: CL604 FLC ENCOUNTERS SEVERE TURB DURING CRUISE.

Narrative: PRIOR TO DEP, THE CAPT AND I DISCUSSED A POSSIBLE RADAR ISSUE WHERE THE ACFT WAS HAVING DIFFICULTY DEPICTING WX. ON THE GND, WE WERE ABLE TO DEPICT A CELL OFF THE END OF RWY 15L, WHICH WAS THE DEP RWY. AFTER DEP, WE NOTED THAT THE RADAR WAS NOT DEPICTING PRECIPITATION AND WE VISUALLY CIRCUMNAVED SEVERAL ISOLATED TSTMS. WHILE ON J29, WE ENTERED INTO A HIGH ALT HAZE LAYER AND SHORTLY THEREAFTER I NOTED A LARGE TSTM DIRECTLY IN FRONT OF US AND PROMPTLY NOTED IT TO THE PF. SINCE OUR VISIBILITY WAS VERY LOW AND WE HAD VERY LITTLE TIME TO REACT, THE CAPT HIT THE SYNC BUTTON AND MADE A HARD R TURN FOR WX AVOIDANCE. WE ENTERED THE CELL AS ITS SMALLEST POINT THROUGH WELL ABOVE OUR CRUISE ATTITUDE. WE IMMEDIATELY EXPERIENCED SEVERE TURB AND HVY RAIN YET AT NO POINT WAS WX DEPICTED ON THE RADAR. AS A RESULT OF THE TURB, WE CLBED AS HIGH AS FL382 AND DSNDED AS LOW AS FL360. ATC NOTED THE ALTDEV AND I BRIEFLY TOLD HIM WHAT HAPPENED. IN MY OPINION, THIS INCIDENT WAS STRICTLY BECAUSE OF A BAD RADAR SYS IN THE ACFT.

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.