Flight crew of air carrier cleared descend down through known VFR traffic.

Attributes
ACN	176102
Time
Date	199104
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : orh
State Reference	MA
Altitude	msl bound lower : 4800 msl bound upper : 4800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : bdl
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other descent other
Route In Use	arrival other
Flight Plan	IFR
Aircraft 2
Operator	other
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 180 flight time total : 7000 flight time type : 4500
ASRS Report	176102
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : airborne less severe other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 2000 vertical : 300
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Approximately 3-4 mins before the incident, we were handed off to bdl approach on frequency 119.0. We had previously been assigned a heading of 090 degrees. Bdl approach assigned us 4000' and a 'further left 10 degrees' heading. They also advised us of a VFR small aircraft under their control, at 10 O'clock and 4500'. At we descended through 4800'[ to our assigned altitude, bdl told us to stop our descent at 5000'. We replied that we were unable to do so, having already passed through 5000'. We stopped our descent at 4800' as bdl told us, 'stop descent, traffic alert.' we also spotted the small aircraft and turned right to a heading of approximately 110 degrees to avoid the traffic.

Original NASA ASRS Text

Title: FLT CREW OF ACR CLEARED DESCEND DOWN THROUGH KNOWN VFR TRAFFIC.

Narrative: APPROX 3-4 MINS BEFORE THE INCIDENT, WE WERE HANDED OFF TO BDL APCH ON FREQ 119.0. WE HAD PREVIOUSLY BEEN ASSIGNED A HDG OF 090 DEGS. BDL APCH ASSIGNED US 4000' AND A 'FURTHER LEFT 10 DEGS' HDG. THEY ALSO ADVISED US OF A VFR SMA UNDER THEIR CTL, AT 10 O'CLOCK AND 4500'. AT WE DSNDED THROUGH 4800'[ TO OUR ASSIGNED ALT, BDL TOLD US TO STOP OUR DSNT AT 5000'. WE REPLIED THAT WE WERE UNABLE TO DO SO, HAVING ALREADY PASSED THROUGH 5000'. WE STOPPED OUR DSNT AT 4800' AS BDL TOLD US, 'STOP DSNT, TFC ALERT.' WE ALSO SPOTTED THE SMA AND TURNED RIGHT TO A HDG OF APPROX 110 DEGS TO AVOID THE TFC.

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.