<< >> NASA ASRS Report 289491, October 1994

TCASII RA.

Attributes
ACN	289491
Time
Date	199410
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : oma
State Reference	NE
Altitude	msl bound lower : 34500 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zkc
Operator	common carrier : air carrier
Make Model Name	DC-10 10
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other cruise other
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	other : unknown
Flight Phase	cruise other cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 20000 flight time type : 1000
ASRS Report	289491
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action other
Consequence	Other
Miss Distance	horizontal : 1500 vertical : 400
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

ZKC had wbound traffic our altitude that resulted in a head-on loss of separation. Captain was aft using lavatory, first officer was on oxygen and flying on autoplt and tracking INS 30 NM south of oma at FL350 eastbound direct bfd. First officer noticed traffic on TCASII at our altitude, and asked ZKC about traffic. Center issued an immediate right 30 degree right turn followed by a request to continue to 40 degrees. TCASII sounded a TA followed immediately by a descending RA, resulting in a descent to 34500 ft until clear of traffic. The miss was 500 ft and approximately 1/4 mi horizontal. Summary: thank god for TCASII! At XA00 am one might be tempted to believe in the 'big sky theory.' no one could possibly be up here this time of night! Even though both aircraft were at their assigned altitude of FL350, we were wrong altitude for direction, something I will be careful about in the future.

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Original NASA ASRS Text

Title: TCASII RA.

Narrative: ZKC HAD WBOUND TFC OUR ALT THAT RESULTED IN A HEAD-ON LOSS OF SEPARATION. CAPT WAS AFT USING LAVATORY, FO WAS ON OXYGEN AND FLYING ON AUTOPLT AND TRACKING INS 30 NM S OF OMA AT FL350 EBOUND DIRECT BFD. FO NOTICED TFC ON TCASII AT OUR ALT, AND ASKED ZKC ABOUT TFC. CTR ISSUED AN IMMEDIATE R 30 DEG R TURN FOLLOWED BY A REQUEST TO CONTINUE TO 40 DEGS. TCASII SOUNDED A TA FOLLOWED IMMEDIATELY BY A DSNDING RA, RESULTING IN A DSCNT TO 34500 FT UNTIL CLR OF TFC. THE MISS WAS 500 FT AND APPROX 1/4 MI HORIZ. SUMMARY: THANK GOD FOR TCASII! AT XA00 AM ONE MIGHT BE TEMPTED TO BELIEVE IN THE 'BIG SKY THEORY.' NO ONE COULD POSSIBLY BE UP HERE THIS TIME OF NIGHT! EVEN THOUGH BOTH ACFT WERE AT THEIR ASSIGNED ALT OF FL350, WE WERE WRONG ALT FOR DIRECTION, SOMETHING I WILL BE CAREFUL ABOUT IN THE FUTURE.

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.