Falcon 50 flight crew experienced an intermittently fluctuating first officer's pitot static system.

Attributes
ACN	839108
Time
Date	200906
Local Time Of Day	0601-1200
Place
Locale Reference	DTW.Airport
State Reference	MI
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	Light Transport
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	SID ACO 2
Flight Plan	IFR
Component
Aircraft Component	Pitot-Static System
Person 1
Function	First Officer
Qualification	Flight Crew Multiengine Flight Crew Sea Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Engineer Flight Crew Instrument
Experience	Flight Crew Last 90 Days 240 Flight Crew Total 7300 Flight Crew Type 180
Events
Anomaly	Aircraft Equipment Problem Less Severe

Narrative:

At 15000 MSL the first officer's altitude and vsi began acting erratically; displaying altitudes in excess of plus one thousand and minus one thousand feet. The vsi indicated the same; one to two thousand plus and minus FPM. The captain's instrument remained constant at 15000 ft and zero vertical speed. ATC then asked what altitude we were maintaining. We replied that we were at 15000 MSL. The erratic indications lasted about 30 seconds and then returned to normal. The system remained normal for the remainder of the flight.

Original NASA ASRS Text

Title: Falcon 50 flight crew experienced an intermittently fluctuating First Officer's pitot static system.

Narrative: At 15000 MSL the First Officer's altitude and VSI began acting erratically; displaying altitudes in excess of plus one thousand and minus one thousand feet. The VSI indicated the same; one to two thousand plus and minus FPM. The Captain's instrument remained constant at 15000 FT and zero vertical speed. ATC then asked what altitude we were maintaining. We replied that we were at 15000 MSL. The erratic indications lasted about 30 seconds and then returned to normal. The system remained normal for the remainder of the flight.

Data retrieved from NASA's ASRS site as of April 2012 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.