An air carrier large transport on final approach to runway 25L at las has an near midair collision with an unknown aircraft while at 3000 ft. Traffic 'popped up' on the large transport's TCASII, but ATCT local controller had no knowledge of any traffic in that area.

Home

Browse by month

Random

Latest

About

Contact

Attributes
ACN	386137
Time
Date	199711
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : las
State Reference	NV
Altitude	msl bound lower : 3000 msl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tower : las
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent : approach landing : go around
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 200 flight time total : 17000 flight time type : 3500
ASRS Report	386137
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : nmac non adherence : published procedure non adherence : far other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action other
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 0 vertical : 100
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

Landing las runway 25L -- clear. Las approach pointed out cessna on runway 25R localizer, abeam of us. Position agreed on TCASII. First officer saw cessna called out to us and watched him fall behind as we passed him and noted that he was well clear behind us. Below 3000 ft MSL, on tower frequency, we got a TCASII 'traffic,' then 'climb' advisory. TCASII traffic showed immediately below us, TCASII showed 200 ft then 100 ft below us, and exactly below our aircraft. Climbed and went around. Traffic popped up -- had a working transponder since it showed altitude on our TCASII. Teleconference with tower and they were confused and claimed to know nothing of any traffic. Tower supervisor assumed that clearance to watch for known traffic now behind us also meant traffic in front of us that was never called out, even though we were within 100 ft vertically and no clearance horizontally. This traffic popped up below us -- we first saw it indicating 200 ft below us, don't know if TCASII indicated if it was level or descending.

Original NASA ASRS Text

Title: AN ACR LGT ON FINAL APCH TO RWY 25L AT LAS HAS AN NMAC WITH AN UNKNOWN ACFT WHILE AT 3000 FT. TFC 'POPPED UP' ON THE LGT'S TCASII, BUT ATCT LCL CTLR HAD NO KNOWLEDGE OF ANY TFC IN THAT AREA.

Narrative: LNDG LAS RWY 25L -- CLR. LAS APCH POINTED OUT CESSNA ON RWY 25R LOC, ABEAM OF US. POS AGREED ON TCASII. FO SAW CESSNA CALLED OUT TO US AND WATCHED HIM FALL BEHIND AS WE PASSED HIM AND NOTED THAT HE WAS WELL CLR BEHIND US. BELOW 3000 FT MSL, ON TWR FREQ, WE GOT A TCASII 'TFC,' THEN 'CLB' ADVISORY. TCASII TFC SHOWED IMMEDIATELY BELOW US, TCASII SHOWED 200 FT THEN 100 FT BELOW US, AND EXACTLY BELOW OUR ACFT. CLBED AND WENT AROUND. TFC POPPED UP -- HAD A WORKING XPONDER SINCE IT SHOWED ALT ON OUR TCASII. TELECONFERENCE WITH TWR AND THEY WERE CONFUSED AND CLAIMED TO KNOW NOTHING OF ANY TFC. TWR SUPVR ASSUMED THAT CLRNC TO WATCH FOR KNOWN TFC NOW BEHIND US ALSO MEANT TFC IN FRONT OF US THAT WAS NEVER CALLED OUT, EVEN THOUGH WE WERE WITHIN 100 FT VERTLY AND NO CLRNC HORIZLY. THIS TFC POPPED UP BELOW US -- WE FIRST SAW IT INDICATING 200 FT BELOW US, DON'T KNOW IF TCASII INDICATED IF IT WAS LEVEL OR DSNDING.

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.