Small aircraft X had less than standard separation from air carrier Y. System error.

Attributes
ACN	141587
Time
Date	199004
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : pae
State Reference	WA
Altitude	msl bound lower : 7000 msl bound upper : 7500
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sea tracon : btr
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 25 flight time total : 300 flight time type : 200
ASRS Report	141587
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified other flight crewa
Resolutory Action	controller : issued new clearance
Consequence	Other
Miss Distance	horizontal : 4000 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Small aircraft X was cruising on IFR clearance, 7000' on V23 after leaving anacortes, wa. Flight started with whidbey NAS control, followed by handoff to seattle TRACON. Seattle TRACON was very busy, providing rapid-fire instructions to many aircraft. Over paine VOR they called with what was interpreted a 'climb 12000''. Both reporter (pilot) and non-licensed, but flight experienced passenger, heard or thought they heard 'climb 12000''. Because this would be somewhat of an unusual profile in this area, readback using aircraft full identification 'nxxxx climbing 12000' instead of the abbreviated 'small aircraft X' that had been used since initial call-up. Within 2 mins, air carrier Y, widebody transport appeared on a parallel path descent on our starboard side. This was not a near miss, but likely an IFR separation violation. When air carrier Y was directly off starboard wing, he was 4000-6000' horizontal and estimated less than 2000' vertical (above) in descent. Small aircraft X was about 7500' and climbing. Vertical separation became 0 as jet continued descent forward (ahead) of reporting aircraft. Controller must have also noticed conflict about the same time as we visually observed. He instructed 'small aircraft X, descent 7000', turn left 120 degree.' no other comments were made. Immediately after, a new controller took over, and flight continued normally.

Original NASA ASRS Text

Title: SMA X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR.

Narrative: SMA X WAS CRUISING ON IFR CLRNC, 7000' ON V23 AFTER LEAVING ANACORTES, WA. FLT STARTED WITH WHIDBEY NAS CTL, FOLLOWED BY HANDOFF TO SEATTLE TRACON. SEATTLE TRACON WAS VERY BUSY, PROVIDING RAPID-FIRE INSTRUCTIONS TO MANY ACFT. OVER PAINE VOR THEY CALLED WITH WHAT WAS INTERPRETED A 'CLIMB 12000''. BOTH RPTR (PLT) AND NON-LICENSED, BUT FLT EXPERIENCED PAX, HEARD OR THOUGHT THEY HEARD 'CLIMB 12000''. BECAUSE THIS WOULD BE SOMEWHAT OF AN UNUSUAL PROFILE IN THIS AREA, READBACK USING ACFT FULL ID 'NXXXX CLIMBING 12000' INSTEAD OF THE ABBREVIATED 'SMA X' THAT HAD BEEN USED SINCE INITIAL CALL-UP. WITHIN 2 MINS, ACR Y, WDB APPEARED ON A PARALLEL PATH DSNT ON OUR STARBOARD SIDE. THIS WAS NOT A NEAR MISS, BUT LIKELY AN IFR SEPARATION VIOLATION. WHEN ACR Y WAS DIRECTLY OFF STARBOARD WING, HE WAS 4000-6000' HORIZONTAL AND ESTIMATED LESS THAN 2000' VERTICAL (ABOVE) IN DSNT. SMA X WAS ABOUT 7500' AND CLIMBING. VERTICAL SEPARATION BECAME 0 AS JET CONTINUED DSNT FORWARD (AHEAD) OF REPORTING ACFT. CTLR MUST HAVE ALSO NOTICED CONFLICT ABOUT THE SAME TIME AS WE VISUALLY OBSERVED. HE INSTRUCTED 'SMA X, DSNT 7000', TURN LEFT 120 DEG.' NO OTHER COMMENTS WERE MADE. IMMEDIATELY AFTER, A NEW CTLR TOOK OVER, AND FLT CONTINUED NORMALLY.

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.