A bonanza pilot encountered wake turbulence behind a B737 while climbing out in IMC.

Attributes
ACN	336830
Time
Date	199605
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : dal airport : ads
State Reference	TX
Altitude	msl bound lower : 3000 msl bound upper : 3400
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dal
Operator	general aviation : personal
Make Model Name	Bonanza 33
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent other
Route In Use	arrival other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Experience	flight time last 90 days : 15 flight time total : 400 flight time type : 15
ASRS Report	336830
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude inflight encounter other other anomaly other
Independent Detector	atc equipment other atc equipment : unspecified other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

I departed ads on heading 100 degrees and 2000 ft altitude. Controller issued right turn to heading 190 degrees and climb to 3000 ft behind passing B737 traffic. After entering clouds, my airplane encountered wake turbulence at approximately 3000 ft. My altitude changed by approximately 100-200 ft causing mode C alert at ATC for altitude display of 3400 ft. Controller asked for altitude verification. I verified at that time 3100 ft. He stated mode C was indicating 3400 ft. Even after returning to 3000 ft, controller issued statement of mode C still indicating 3400 ft and issued 'stop mode C squawk.' prevention: controllers should provide more separation between light and heavy aircraft prior to issuing vectors for intersecting paths. Also, I feel that wake turbulence caused mode C pressure problem causing inaccurate mode C output.

Original NASA ASRS Text

Title: A BONANZA PLT ENCOUNTERED WAKE TURB BEHIND A B737 WHILE CLBING OUT IN IMC.

Narrative: I DEPARTED ADS ON HDG 100 DEGS AND 2000 FT ALT. CTLR ISSUED R TURN TO HDG 190 DEGS AND CLB TO 3000 FT BEHIND PASSING B737 TFC. AFTER ENTERING CLOUDS, MY AIRPLANE ENCOUNTERED WAKE TURB AT APPROX 3000 FT. MY ALT CHANGED BY APPROX 100-200 FT CAUSING MODE C ALERT AT ATC FOR ALT DISPLAY OF 3400 FT. CTLR ASKED FOR ALT VERIFICATION. I VERIFIED AT THAT TIME 3100 FT. HE STATED MODE C WAS INDICATING 3400 FT. EVEN AFTER RETURNING TO 3000 FT, CTLR ISSUED STATEMENT OF MODE C STILL INDICATING 3400 FT AND ISSUED 'STOP MODE C SQUAWK.' PREVENTION: CTLRS SHOULD PROVIDE MORE SEPARATION BTWN LIGHT AND HVY ACFT PRIOR TO ISSUING VECTORS FOR INTERSECTING PATHS. ALSO, I FEEL THAT WAKE TURB CAUSED MODE C PRESSURE PROB CAUSING INACCURATE MODE C OUTPUT.

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.