<< >> NASA ASRS Report 403988, May 1998

2 aircraft at same altitude at day on crossing paths are noticed by controllers and at the last min action is taken to provide separation. The incident resulted in an operational error.

Attributes
ACN	403988
Time
Date	199805
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : rid
State Reference	OH
Altitude	msl bound lower : 8000 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : day
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
ASRS Report	403988
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance none taken : unable other
Consequence	Other
Miss Distance	horizontal : 3000 vertical : 200
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Two IFR en route aircraft were both at 8000 ft on crossing paths. Controller unaware of closure, warned at last moment by other controller. Collision avoidance system alert also at last moment (approximately 1 mi). Aircraft 'a,' nwbound, was given an immediate descent. Aircraft 'B,' swbound, was given a turn. Aircraft 'a' began descent but did not reply orally. Aircraft 'B' did not respond or acknowledge turn. Aircraft 'a' reported aircraft 'B' in sight. Aircraft 'B' called second time. Sees aircraft 'a' passing beneath. Aircraft pass less than 1/2 mi at approximately 200 ft. Aircraft 'a' was climbed back to en route altitude.

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Original NASA ASRS Text

Title: 2 ACFT AT SAME ALT AT DAY ON XING PATHS ARE NOTICED BY CTLRS AND AT THE LAST MIN ACTION IS TAKEN TO PROVIDE SEPARATION. THE INCIDENT RESULTED IN AN OPERROR.

Narrative: TWO IFR ENRTE ACFT WERE BOTH AT 8000 FT ON XING PATHS. CTLR UNAWARE OF CLOSURE, WARNED AT LAST MOMENT BY OTHER CTLR. COLLISION AVOIDANCE SYS ALERT ALSO AT LAST MOMENT (APPROX 1 MI). ACFT 'A,' NWBOUND, WAS GIVEN AN IMMEDIATE DSCNT. ACFT 'B,' SWBOUND, WAS GIVEN A TURN. ACFT 'A' BEGAN DSCNT BUT DID NOT REPLY ORALLY. ACFT 'B' DID NOT RESPOND OR ACKNOWLEDGE TURN. ACFT 'A' RPTED ACFT 'B' IN SIGHT. ACFT 'B' CALLED SECOND TIME. SEES ACFT 'A' PASSING BENEATH. ACFT PASS LESS THAN 1/2 MI AT APPROX 200 FT. ACFT 'A' WAS CLBED BACK TO ENRTE ALT.

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.