Cpr X had less than standard separation from air carrier Z. Pilot deviation. System error.

Attributes
ACN	172337
Time
Date	199103
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mlg
State Reference	UT
Altitude	msl bound lower : 26000 msl bound upper : 26000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zlc tower : cle
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
ASRS Report	172337
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : required legal separation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated
Miss Distance	horizontal : 24000 vertical : 0
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Operational Error Pilot Deviation

Narrative:

Cpr X check on level FL230, I then climbed cpr Y to FL260 cpr X said 'cpr X climbing to FL350.' this occurred because both pilot and controller missed restriction to altitude/readback. Air carrier Z was westbound FL260. Cpr X was nwbnd, climbing extremely fast, cpr X broke altitude of FL250. At FL256 controller said verify assigned altitude FL250, cpr X said I thought it was FL350. Controller said cpr X turn 90 degree left immediately. I then said air carrier Z turn right heading 300 immediately. Controller then observed cpr X at FL261 climbing so controller said expedite climb to FL350, traffic at 2 O'clock 4 mi wnwbound FL260. Cpr X said roger we're out of FL270. Closest proximity was same altitude 4 mi.

Original NASA ASRS Text

Title: CPR X HAD LESS THAN STANDARD SEPARATION FROM ACR Z. PLTDEV. SYSTEM ERROR.

Narrative: CPR X CHK ON LEVEL FL230, I THEN CLBED CPR Y TO FL260 CPR X SAID 'CPR X CLBING TO FL350.' THIS OCCURRED BECAUSE BOTH PLT AND CTLR MISSED RESTRICTION TO ALT/READBACK. ACR Z WAS WBND FL260. CPR X WAS NWBND, CLBING EXTREMELY FAST, CPR X BROKE ALT OF FL250. AT FL256 CTLR SAID VERIFY ASSIGNED ALT FL250, CPR X SAID I THOUGHT IT WAS FL350. CTLR SAID CPR X TURN 90 DEG L IMMEDIATELY. I THEN SAID ACR Z TURN R HDG 300 IMMEDIATELY. CTLR THEN OBSERVED CPR X AT FL261 CLBING SO CTLR SAID EXPEDITE CLB TO FL350, TFC AT 2 O'CLOCK 4 MI WNWBOUND FL260. CPR X SAID ROGER WE'RE OUT OF FL270. CLOSEST PROX WAS SAME ALT 4 MI.

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.