<< >> NASA ASRS Report 201508, February 1992

Air carrier X TCASII RA evasive action taken unauthorized climb had less than standard separation from light transport Y. Pilot deviation.

Attributes
ACN	201508
Time
Date	199202
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : ord
State Reference	IL
Altitude	msl bound lower : 4000 msl bound upper : 5500
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : ord
Operator	common carrier : air carrier
Make Model Name	Medium Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Light Transport, High Wing, 2 Turboprop Eng
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
ASRS Report	201508
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : required legal separation other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 9000 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was vectoring to the 'high side' (runway 27L) on simultaneous ILS approachs. Air carrier X was level at 5000 ft on a left base. A company light transport was on a left downwind at 6000 ft when the air carrier X was approximately 3 mi from the 27L localizer, he received TCASII RA instructing him to climb. The RA was initiated due to traffic level at 4000 ft on the parallel runway. When air carrier X climbed, the light transport was approximately 1.5 mi behind him. Air carrier X climbed 500 ft to 5500 ft before he descended back down. Air carrier X never received an RA for the light transport that was now only 500 ft above him. All of this occurred during the middle of a heavy arrival rush into O'hare. Not only did it divert my attention, it also caused undue frequency congestion. TCASII is a dangerous tool when operating in a high density area. The above shows that it is not flawless. Air carrier X received an RA (for traffic he was already above) to climb into another aircraft that was above him. Suspend the RA mode or at least parallel approachs to avoid this situation from recurring.

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Original NASA ASRS Text

Title: ACR X TCASII RA EVASIVE ACTION TAKEN UNAUTH CLB HAD LTSS FROM LTT Y. PLTDEV.

Narrative: I WAS VECTORING TO THE 'HIGH SIDE' (RWY 27L) ON SIMULTANEOUS ILS APCHS. ACR X WAS LEVEL AT 5000 FT ON A L BASE. A COMPANY LTT WAS ON A L DOWNWIND AT 6000 FT WHEN THE ACR X WAS APPROX 3 MI FROM THE 27L LOC, HE RECEIVED TCASII RA INSTRUCTING HIM TO CLB. THE RA WAS INITIATED DUE TO TFC LEVEL AT 4000 FT ON THE PARALLEL RWY. WHEN ACR X CLBED, THE LTT WAS APPROX 1.5 MI BEHIND HIM. ACR X CLBED 500 FT TO 5500 FT BEFORE HE DSNDED BACK DOWN. ACR X NEVER RECEIVED AN RA FOR THE LTT THAT WAS NOW ONLY 500 FT ABOVE HIM. ALL OF THIS OCCURRED DURING THE MIDDLE OF A HVY ARR RUSH INTO O'HARE. NOT ONLY DID IT DIVERT MY ATTN, IT ALSO CAUSED UNDUE FREQ CONGESTION. TCASII IS A DANGEROUS TOOL WHEN OPERATING IN A HIGH DENSITY AREA. THE ABOVE SHOWS THAT IT IS NOT FLAWLESS. ACR X RECEIVED AN RA (FOR TFC HE WAS ALREADY ABOVE) TO CLB INTO ANOTHER ACFT THAT WAS ABOVE HIM. SUSPEND THE RA MODE OR AT LEAST PARALLEL APCHS TO AVOID THIS SITUATION FROM RECURRING.

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.