Air carrier X had less than standard separation from small aircraft Y. System error.

Attributes
ACN	185364
Time
Date	199108
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : pit
State Reference	PA
Altitude	msl bound lower : 4500 msl bound upper : 4500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : pit
Operator	common carrier : air carrier
Make Model Name	Medium Large 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 : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Route In Use	enroute : direct
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 8500 flight time type : 5000
ASRS Report	185364
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 180 flight time total : 10000 flight time type : 180
ASRS Report	185356
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	other flight crewa
Resolutory Action	none taken : insufficient time
Consequence	Other
Miss Distance	horizontal : 3000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X received departure clearance from tower to climb and maintain 4000 ft. (Normal for pit is 5000 ft). After airborne we were told to contact departure control (119.35). On initial contact with departure control, we were told to climb to 5000 ft; and were issued VFR traffic advisory for small aircraft Y at 4500 ft. This clearance would have us climbing through his altitude but controller had us both in radar contact and we light (ferry flight) and climbing very fast. I assumed the controller thought we would be level at 5000 ft before the traffic became a factor. The 5000 ft altitude assignment was read back by first officer on radio and he set 5000 ft in altitude alerter. I confirmed '5000 ft'. As we climbed through 4500 ft I spotted the small aircraft Y off my left shoulder at approximately 1/2 mi. Controller simultaneously said 'maintain assigned altitude 4000 ft.' we were level at 5000 ft and told controller he had assigned us 5000 ft. He said he was saving tape to check. A couple mins later he confirmed on the radio that it was his mistake. Small aircraft Y stated that 'was too close.'

Original NASA ASRS Text

Title: ACR X HAD LTSS FROM SMA Y. SYS ERROR.

Narrative: ACR X RECEIVED DEP CLRNC FROM TWR TO CLB AND MAINTAIN 4000 FT. (NORMAL FOR PIT IS 5000 FT). AFTER AIRBORNE WE WERE TOLD TO CONTACT DEP CTL (119.35). ON INITIAL CONTACT WITH DEP CTL, WE WERE TOLD TO CLB TO 5000 FT; AND WERE ISSUED VFR TFC ADVISORY FOR SMA Y AT 4500 FT. THIS CLRNC WOULD HAVE US CLBING THROUGH HIS ALT BUT CTLR HAD US BOTH IN RADAR CONTACT AND WE LIGHT (FERRY FLT) AND CLBING VERY FAST. I ASSUMED THE CTLR THOUGHT WE WOULD BE LEVEL AT 5000 FT BEFORE THE TFC BECAME A FACTOR. THE 5000 FT ALT ASSIGNMENT WAS READ BACK BY FO ON RADIO AND HE SET 5000 FT IN ALT ALERTER. I CONFIRMED '5000 FT'. AS WE CLBED THROUGH 4500 FT I SPOTTED THE SMA Y OFF MY L SHOULDER AT APPROX 1/2 MI. CTLR SIMULTANEOUSLY SAID 'MAINTAIN ASSIGNED ALT 4000 FT.' WE WERE LEVEL AT 5000 FT AND TOLD CTLR HE HAD ASSIGNED US 5000 FT. HE SAID HE WAS SAVING TAPE TO CHK. A COUPLE MINS LATER HE CONFIRMED ON THE RADIO THAT IT WAS HIS MISTAKE. SMA Y STATED THAT 'WAS TOO CLOSE.'

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.