Medium large transport climbs above assigned altitude causing conflict.

Attributes
ACN	247254
Time
Date	199307
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : tlh
State Reference	FL
Altitude	msl bound lower : 23000 msl bound upper : 27500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx tower : dfw
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 200 flight time total : 3900 flight time type : 230
ASRS Report	247254
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 220 flight time total : 9000 flight time type : 2500
ASRS Report	247132
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 7000 vertical : 1500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Took off and headed northwest. Initial climb clearance to 12000, restr to 250 KTS. Deviated slightly around small thunderstorms in vicinity, got and read back next clearance to 'FL230, normal speed after 180.' leveled FL230, got new climb clearance to 'FL290, traffic 3 O'clock, 20 mi, FL270.' I read back (on frequency 125.17) 'climbing to FL290, now receiving tlh, request direct.' controller responded, 'cleared direct' (and I believe he also said climb to FL290). I then read back, 'climbing FL290, direct tlh.' I saw traffic at approximately same time as TCASII advisory 'traffic, traffic.' no threat of collision as below and moving across the windscreen. Elected to stay above traffic, holding approximately 27600 ft as traffic passed. Controller immediately queried altitude and, upon hearing me report 'through 27500 for FL290, traffic in sight,' asked where we got such a clearance. Conflict resolved, and then asked and leveled at FL280. Subsequent climb to FL310, back on routing. Autoplt altitude arming/climb procedures all performed in accordance with flight manual, and all system worked as advertised. I believe this incident to be caused by incorrect climb clearance from controller, and then he didn't catch subsequent readbacks. There is a possibility of confusion due to '6' vs '9,' our early heading of '290 degrees' while deviating around WX, and our call sign of XXXX9. Both cockpit crewmembers believe FL290 was the altitude cleared to.

Original NASA ASRS Text

Title: MLG CLBS ABOVE ASSIGNED ALT CAUSING CONFLICT.

Narrative: TOOK OFF AND HEADED NW. INITIAL CLB CLRNC TO 12000, RESTR TO 250 KTS. DEVIATED SLIGHTLY AROUND SMALL TSTMS IN VICINITY, GOT AND READ BACK NEXT CLRNC TO 'FL230, NORMAL SPD AFTER 180.' LEVELED FL230, GOT NEW CLB CLRNC TO 'FL290, TFC 3 O'CLOCK, 20 MI, FL270.' I READ BACK (ON FREQ 125.17) 'CLBING TO FL290, NOW RECEIVING TLH, REQUEST DIRECT.' CTLR RESPONDED, 'CLRED DIRECT' (AND I BELIEVE HE ALSO SAID CLB TO FL290). I THEN READ BACK, 'CLBING FL290, DIRECT TLH.' I SAW TFC AT APPROX SAME TIME AS TCASII ADVISORY 'TFC, TFC.' NO THREAT OF COLLISION AS BELOW AND MOVING ACROSS THE WINDSCREEN. ELECTED TO STAY ABOVE TFC, HOLDING APPROX 27600 FT AS TFC PASSED. CTLR IMMEDIATELY QUERIED ALT AND, UPON HEARING ME RPT 'THROUGH 27500 FOR FL290, TFC IN SIGHT,' ASKED WHERE WE GOT SUCH A CLRNC. CONFLICT RESOLVED, AND THEN ASKED AND LEVELED AT FL280. SUBSEQUENT CLB TO FL310, BACK ON RTING. AUTOPLT ALT ARMING/CLB PROCS ALL PERFORMED IN ACCORDANCE WITH FLT MANUAL, AND ALL SYS WORKED AS ADVERTISED. I BELIEVE THIS INCIDENT TO BE CAUSED BY INCORRECT CLB CLRNC FROM CTLR, AND THEN HE DIDN'T CATCH SUBSEQUENT READBACKS. THERE IS A POSSIBILITY OF CONFUSION DUE TO '6' VS '9,' OUR EARLY HDG OF '290 DEGS' WHILE DEVIATING AROUND WX, AND OUR CALL SIGN OF XXXX9. BOTH COCKPIT CREWMEMBERS BELIEVE FL290 WAS THE ALT CLRED TO.

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.