Air carrier X had less than standard separation from air carrier Y. System error. Air carrier Y TCASII RA unauthorized descent into air carrier X.

Home

Browse by month

Random

Latest

About

Contact

Attributes
ACN	202322
Time
Date	199202
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : phx
State Reference	AZ
Altitude	msl bound lower : 31000 msl bound upper : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zab
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : non radar
Qualification	controller : non radar
ASRS Report	202322
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : published procedure non adherence : required legal separation non adherence : clearance other anomaly other
Independent Detector	atc equipment other atc equipment : unspecified aircraft equipment other aircraft equipment : unspecified
Resolutory Action	none taken : insufficient time
Consequence	faa : investigated
Miss Distance	horizontal : 18000 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I was working as the manual controller on sector 39. Traffic was moderate. I marked the flight progress strip for air carrier X as appropriate and consistent with a common descent clearance into phx. A short time later I was relieved of my position and briefed the incoming controller accordingly. I did not observe any situations that required any immediate action of notification to the radar controller. Neither did my relief as he indicated everything looked good that he 'had it.' 5 mins later the separation was lost between air carrier X and air carrier Y as air carrier X descended through the altitude of air carrier Y overflt. I was asked to fill out a statement on the incident even though I had no knowledge of it. As an interesting side note: air carrier X was below air carrier Y and head on to him when the air carrier Y pilot said he had a TCASII resolution to descend and he did so. This action actually reduced what separation there was!

Original NASA ASRS Text

Title: ACR X HAD LTSS FROM ACR Y. SYS ERROR. ACR Y TCASII RA UNAUTHORIZED DSCNT INTO ACR X.

Narrative: I WAS WORKING AS THE MANUAL CTLR ON SECTOR 39. TFC WAS MODERATE. I MARKED THE FLT PROGRESS STRIP FOR ACR X AS APPROPRIATE AND CONSISTENT WITH A COMMON DSCNT CLRNC INTO PHX. A SHORT TIME LATER I WAS RELIEVED OF MY POS AND BRIEFED THE INCOMING CTLR ACCORDINGLY. I DID NOT OBSERVE ANY SITUATIONS THAT REQUIRED ANY IMMEDIATE ACTION OF NOTIFICATION TO THE RADAR CTLR. NEITHER DID MY RELIEF AS HE INDICATED EVERYTHING LOOKED GOOD THAT HE 'HAD IT.' 5 MINS LATER THE SEPARATION WAS LOST BTWN ACR X AND ACR Y AS ACR X DSNDED THROUGH THE ALT OF ACR Y OVERFLT. I WAS ASKED TO FILL OUT A STATEMENT ON THE INCIDENT EVEN THOUGH I HAD NO KNOWLEDGE OF IT. AS AN INTERESTING SIDE NOTE: ACR X WAS BELOW ACR Y AND HEAD ON TO HIM WHEN THE ACR Y PLT SAID HE HAD A TCASII RESOLUTION TO DSND AND HE DID SO. THIS ACTION ACTUALLY REDUCED WHAT SEPARATION THERE WAS!

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.