Small aircraft Y had near midair collision less than standard separation with air carrier Y in dca T...

Attributes
ACN	177433
Time
Date	199103
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : dca
State Reference	DC
Altitude	msl bound lower : 4100 msl bound upper : 4500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dca
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other descent other
Route In Use	enroute : direct
Flight Plan	None
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Transport
Flight Phase	cruise other
Route In Use	enroute : direct
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 8 flight time total : 85 flight time type : 40
ASRS Report	177433
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : nmac non adherence : published procedure non adherence : required legal separation
Independent Detector	other controllera
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 0 vertical : 400
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Small aircraft X was cruising at 6500' on V170 when cleared into the TCA for landing at dca. After swann turned on V123 to dca, baltimore approach ordered a descent to 4500'. We were then handed off to dca approach. After leveling off at 4500' and cruising for about 5 mins, approach called out, 'small aircraft X traffic at 12 O'clock.' at that instant I saw an aircraft at the sam altitude (4500'), headed straight for me. It looked like a 4 engine turbo propeller air carrier Y. I immediately cut power and went into a steep dive. When the other aircraft passed over I was at 4150'. The other aircraft appeared to take no evasive action. He may not have even seen us until it was too late. My descent rate was approximately 1500 FPM, so the warning time was very short. We would have hit nose to nose!

Original NASA ASRS Text

Title: SMA Y HAD NMAC LESS THAN STANDARD SEPARATION WITH ACR Y IN DCA TCA. SYSTEM ERROR.

Narrative: SMA X WAS CRUISING AT 6500' ON V170 WHEN CLRED INTO THE TCA FOR LNDG AT DCA. AFTER SWANN TURNED ON V123 TO DCA, BALTIMORE APCH ORDERED A DSNT TO 4500'. WE WERE THEN HANDED OFF TO DCA APCH. AFTER LEVELING OFF AT 4500' AND CRUISING FOR ABOUT 5 MINS, APCH CALLED OUT, 'SMA X TFC AT 12 O'CLOCK.' AT THAT INSTANT I SAW AN ACFT AT THE SAM ALT (4500'), HEADED STRAIGHT FOR ME. IT LOOKED LIKE A 4 ENG TURBO PROP ACR Y. I IMMEDIATELY CUT PWR AND WENT INTO A STEEP DIVE. WHEN THE OTHER ACFT PASSED OVER I WAS AT 4150'. THE OTHER ACFT APPEARED TO TAKE NO EVASIVE ACTION. HE MAY NOT HAVE EVEN SEEN US UNTIL IT WAS TOO LATE. MY DSNT RATE WAS APPROX 1500 FPM, SO THE WARNING TIME WAS VERY SHORT. WE WOULD HAVE HIT NOSE TO NOSE!

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.

Small aircraft Y had near midair collision less than standard separation with air carrier Y in dca TCA. System error.