Loss of separation near swl, md.

Attributes
ACN	477736
Time
Date	200006
Day	Thu
Place
Locale Reference	navaid : swl.vortac
State Reference	MD
Altitude	msl bound lower : 28500 msl bound upper : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc.artcc
Operator	common carrier : air carrier
Make Model Name	B717
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : enroute altitude change
Route In Use	enroute airway : j121.airway
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zdc.artcc
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
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 : 19000 flight time type : 16000
ASRS Report	477736
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Events
Anomaly	conflict : airborne critical non adherence : published procedure
Independent Detector	aircraft equipment : tcas other controllerb
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Miss Distance	horizontal : 6000 vertical : 800
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

We were cruising at FL290 at about XA10 EDT on a flight from fll to phl. ZDC cleared us to descend to FL260. We read back the clearance and started our descent. Center told us to stop descent at FL290. About the same time we got a TCASII RA and climbed back to FL290. Our lowest altitude was FL285. As I was climbing back up, I saw a B737 go under us about 1 mi to our east, at FL280.

Original NASA ASRS Text

Title: LOSS OF SEPARATION NEAR SWL, MD.

Narrative: WE WERE CRUISING AT FL290 AT ABOUT XA10 EDT ON A FLT FROM FLL TO PHL. ZDC CLRED US TO DSND TO FL260. WE READ BACK THE CLRNC AND STARTED OUR DSCNT. CTR TOLD US TO STOP DSCNT AT FL290. ABOUT THE SAME TIME WE GOT A TCASII RA AND CLBED BACK TO FL290. OUR LOWEST ALT WAS FL285. AS I WAS CLBING BACK UP, I SAW A B737 GO UNDER US ABOUT 1 MI TO OUR E, AT FL280.

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.