Small aircraft X pilot loses aircraft control on taxi due rotor downwash from hovering helicopter.

Attributes
ACN	178054
Time
Date	199105
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : sql
State Reference	CA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	ground other : taxi
Flight Plan	None
Aircraft 2
Make Model Name	Helicopter
Flight Phase	ground other : taxi other
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp pilot : flight engineer
Experience	flight time total : 3500
ASRS Report	178054
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	other anomaly other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Ground gave clearance to taxi to hangar and issued, 'caution wake turbulence from helicopter,' referring to a helicopter (small aircraft Y) hovering adjacent to taxiway. I was in a small experimental aircraft (small aircraft X) in wind conditions (approximately 15 KTS). My inexperience and inadequate knowledge caused me to lose control of the aircraft and scrape trailing edge of the wing tip. Only light abrasion--no other damage. The only helicopter I'm really familiar with is light with a very large rotor span and doesn't create a great deal of wash. Apparently the helicopter in this instance has a short rotor span with much more powerful downwash. This coupled with its hovering confign made my decision to taxi very unsafe.

Original NASA ASRS Text

Title: SMA X PLT LOSES ACFT CTL ON TAXI DUE ROTOR DOWNWASH FROM HOVERING HELICOPTER.

Narrative: GND GAVE CLRNC TO TAXI TO HANGAR AND ISSUED, 'CAUTION WAKE TURB FROM HELI,' REFERRING TO A HELI (SMA Y) HOVERING ADJACENT TO TXWY. I WAS IN A SMALL EXPERIMENTAL ACFT (SMA X) IN WIND CONDITIONS (APPROX 15 KTS). MY INEXPERIENCE AND INADEQUATE KNOWLEDGE CAUSED ME TO LOSE CTL OF THE ACFT AND SCRAPE TRAILING EDGE OF THE WING TIP. ONLY LIGHT ABRASION--NO OTHER DAMAGE. THE ONLY HELI I'M REALLY FAMILIAR WITH IS LIGHT WITH A VERY LARGE ROTOR SPAN AND DOESN'T CREATE A GREAT DEAL OF WASH. APPARENTLY THE HELI IN THIS INSTANCE HAS A SHORT ROTOR SPAN WITH MUCH MORE POWERFUL DOWNWASH. THIS COUPLED WITH ITS HOVERING CONFIGN MADE MY DECISION TO TAXI VERY UNSAFE.

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.