Turbulence from other aircraft wake produces strong effect during air races.

Attributes
ACN	316126
Time
Date	199509
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : 4sd
State Reference	NV
Altitude	msl bound lower : 5000 msl bound upper : 5000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Experimental
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 70 flight time total : 10500 flight time type : 10
ASRS Report	316126
Person 2
Affiliation	Other
Function	oversight : airport manager
Qualification	other other : other
Events
Anomaly	inflight encounter other
Independent Detector	other flight crewa
Resolutory Action	flight crew : regained aircraft control
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

Participating in biplane class race at airshow. On third pylon of 4TH or 5TH lap encountered strong vortices from other aircraft at race. While recovering, with other aircraft above, inadvertently may have gone below ht of top of pylon. Did not think so at time. In fact could see into top of pylon prior to turbulence encounter, but officials at pylon reported low pass by. While some turbulence had been anticipated, 2 other aircraft had just passed from above (out of my view) and turbulence was much stronger than encountered prior, a real learning experience!

Original NASA ASRS Text

Title: TURB FROM OTHER ACFT WAKE PRODUCES STRONG EFFECT DURING AIR RACES.

Narrative: PARTICIPATING IN BIPLANE CLASS RACE AT AIRSHOW. ON THIRD PYLON OF 4TH OR 5TH LAP ENCOUNTERED STRONG VORTICES FROM OTHER ACFT AT RACE. WHILE RECOVERING, WITH OTHER ACFT ABOVE, INADVERTENTLY MAY HAVE GONE BELOW HT OF TOP OF PYLON. DID NOT THINK SO AT TIME. IN FACT COULD SEE INTO TOP OF PYLON PRIOR TO TURB ENCOUNTER, BUT OFFICIALS AT PYLON RPTED LOW PASS BY. WHILE SOME TURB HAD BEEN ANTICIPATED, 2 OTHER ACFT HAD JUST PASSED FROM ABOVE (OUT OF MY VIEW) AND TURB WAS MUCH STRONGER THAN ENCOUNTERED PRIOR, A REAL LEARNING EXPERIENCE!

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.