<< >> NASA ASRS Report 186665, August 1991

Close proximity air carrier-medium large transport air carrier-medium large transport plus altitude deviation excursion from clearance altitude in response to TCASII RA.

Attributes
ACN	186665
Time
Date	199108
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : djb airport : cle
State Reference	OH
Altitude	msl bound lower : 10000 msl bound upper : 11000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : cle
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : atp pilot : instrument pilot : private pilot : flight engineer
Experience	flight time last 90 days : 195 flight time total : 15000 flight time type : 3200
ASRS Report	186665
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 750 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error other

Narrative:

While in a left turn at 10000 ft to djb VOR to hold, we emerged from the clouds into a small clear area and immediately received a 'TA' from TCASII followed in 2-3 seconds by an RA to climb. We initiated a climb and at the same instant I observed an air carrier medium large transport Y emerge from the clouds at our 1 O'clock position, level with us, approximately 1 mi away on a converging course. During this time, TCASII issued an 'increase climb' command showing approximately 3000 FPM rate of climb required. I told approach we were climbing due to TCASII RA and visual sighting. At this time, cleveland approach instructed us to climb to 11000 ft. I estimate we passed 400-500 ft above and slightly behind the medium large transport Y. After landing, I called the TRACON supervisor who advised me that we had 1000 ft vertical separation within 3 mi of each other. TCASII and our eyes disagree with that.

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Original NASA ASRS Text

Title: CLOSE PROX ACR-MLG ACR-MLG PLUS ALT DEV EXCURSION FROM CLRNC ALT IN RESPONSE TO TCASII RA.

Narrative: WHILE IN A L TURN AT 10000 FT TO DJB VOR TO HOLD, WE EMERGED FROM THE CLOUDS INTO A SMALL CLR AREA AND IMMEDIATELY RECEIVED A 'TA' FROM TCASII FOLLOWED IN 2-3 SECONDS BY AN RA TO CLB. WE INITIATED A CLB AND AT THE SAME INSTANT I OBSERVED AN ACR MLG Y EMERGE FROM THE CLOUDS AT OUR 1 O'CLOCK POS, LEVEL WITH US, APPROX 1 MI AWAY ON A CONVERGING COURSE. DURING THIS TIME, TCASII ISSUED AN 'INCREASE CLB' COMMAND SHOWING APPROX 3000 FPM RATE OF CLB REQUIRED. I TOLD APCH WE WERE CLBING DUE TO TCASII RA AND VISUAL SIGHTING. AT THIS TIME, CLEVELAND APCH INSTRUCTED US TO CLB TO 11000 FT. I ESTIMATE WE PASSED 400-500 FT ABOVE AND SLIGHTLY BEHIND THE MLG Y. AFTER LNDG, I CALLED THE TRACON SUPVR WHO ADVISED ME THAT WE HAD 1000 FT VERT SEPARATION WITHIN 3 MI OF EACH OTHER. TCASII AND OUR EYES DISAGREE WITH THAT.

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.