<< >> NASA ASRS Report 408512, July 1998

A B727 is given descent clearance from las approach control down through an altitude occupied by a VFR cessna. TCASII has the B727 execute an evasive action. Near midair collision.

Attributes
ACN	408512
Time
Date	199807
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : las
State Reference	NV
Altitude	msl bound lower : 9700 msl bound upper : 9700
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : las
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival other enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Cessna Single Piston Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 9000 flight time type : 5000
ASRS Report	408512
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : nmac non adherence : published procedure
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 350 vertical : 250
Supplementary
Primary Problem	ATC Human Performance

Narrative:

On runway 25L las approach 30 DME out, cleared to 8000 ft by ATC. Descending out of 9700 ft got a TCASII TA with immediate RA to climb. Traffic depicted on TCASII about 1/2 mi ahead and 300 ft below us. Immediate evasive action taken to avoid VFR light cessna below, not in contact with ATC and not yet within the TCA. Eventual visual with the wbound traffic showed us about 300 ft above and at least 500 ft horizontal. Continued approach to uneventful landing. Traffic was never called out to us by ATC.

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Original NASA ASRS Text

Title: A B727 IS GIVEN DSCNT CLRNC FROM LAS APCH CTL DOWN THROUGH AN ALT OCCUPIED BY A VFR CESSNA. TCASII HAS THE B727 EXECUTE AN EVASIVE ACTION. NMAC.

Narrative: ON RWY 25L LAS APCH 30 DME OUT, CLRED TO 8000 FT BY ATC. DSNDING OUT OF 9700 FT GOT A TCASII TA WITH IMMEDIATE RA TO CLB. TFC DEPICTED ON TCASII ABOUT 1/2 MI AHEAD AND 300 FT BELOW US. IMMEDIATE EVASIVE ACTION TAKEN TO AVOID VFR LIGHT CESSNA BELOW, NOT IN CONTACT WITH ATC AND NOT YET WITHIN THE TCA. EVENTUAL VISUAL WITH THE WBOUND TFC SHOWED US ABOUT 300 FT ABOVE AND AT LEAST 500 FT HORIZ. CONTINUED APCH TO UNEVENTFUL LNDG. TFC WAS NEVER CALLED OUT TO US BY ATC.

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.