On approach to dfw at 11000' MSL flight crew of medium large transport received TCAS ii RA and climb...

Attributes
ACN	173885
Time
Date	199103
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : dfw
State Reference	TX
Altitude	msl bound lower : 11000 msl bound upper : 11400
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dfw
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude cruise other descent other
Route In Use	arrival other arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 160 flight time total : 5700 flight time type : 105
ASRS Report	173885
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 145 flight time total : 5000 flight time type : 250
ASRS Report	173888
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	vertical : 1000
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was serving as first officer on a TCAS equipped aircraft on a flight from rdu to dfw. We were located on the sfw 117 right inbound, approximately 15 DME, at our assigned altitude of 11000', in contact with dfw approach, with the captain at the controls. Flight conditions were VMC between cloud layers, high overcast above, and overcast below with cloud tops at about 8000-9000'. Then the TCAS startled us with a 'traffic, traffic' aural warning. The radar and my vsi showed a yellow DOT with a -18 at our 2 O'clock position 3-4 mi climbing on a converging course. I immediately scanned outside for the traffic. Within 10 seconds the TCAS was giving us an aural 'climb', the traffic was now displayed in red with a -12, and the vsi now was showing a red arc from zero on down, and a green arc starting at about 1000 FPM rate of climb. The captain and I were not able to make visibility contact. The captain meanwhile had already disconnected the autoplt and started an immediate climb and directed me to notify ATC. This was almost immediately followed by a 'monitor vertical speed' and no red or green arc display. I advised approach that we were deviating for a TA. In fact we were deviating for a RA and I cannot recall if I told them we were climbing. By the time approach responded to confirm my radio transmission, we were level at 11400'. Approach advised us that the traffic was assigned 10000' (no mention was made if he was actually at 10000'). The captain descended back to 11000' and approach control made no further comment about the incident. As an afterthought, if an aircraft climbing or descending to an assigned altitude can set off a TCAS RA in another aircraft, it then becomes incumbent on ATC to advise pilots in both VMC and IMC of altitude assignments of potential 'conflict' aircraft (as if ATC doesn't have enough to do). In high density traffic areas equipped with a system that uses vertical only commands to resolve traffic conflicts, it is not too difficult to envision one aircraft complying with a RA becoming a RA for another. Much like falling dominos.

Original NASA ASRS Text

Title: ON APCH TO DFW AT 11000' MSL FLT CREW OF MLG RECEIVED TCAS II RA AND CLIMBED TO 11400' BEFORE ERASING THE RA. TRAFFIC WAS REPORTED AT 10000'.

Narrative: I WAS SERVING AS F/O ON A TCAS EQUIPPED ACFT ON A FLT FROM RDU TO DFW. WE WERE LOCATED ON THE SFW 117 R INBND, APPROX 15 DME, AT OUR ASSIGNED ALT OF 11000', IN CONTACT WITH DFW APCH, WITH THE CAPT AT THE CTLS. FLT CONDITIONS WERE VMC BTWN CLOUD LAYERS, HIGH OVCST ABOVE, AND OVCST BELOW WITH CLOUD TOPS AT ABOUT 8000-9000'. THEN THE TCAS STARTLED US WITH A 'TFC, TFC' AURAL WARNING. THE RADAR AND MY VSI SHOWED A YELLOW DOT WITH A -18 AT OUR 2 O'CLOCK POS 3-4 MI CLBING ON A CONVERGING COURSE. I IMMEDIATELY SCANNED OUTSIDE FOR THE TFC. WITHIN 10 SECS THE TCAS WAS GIVING US AN AURAL 'CLB', THE TFC WAS NOW DISPLAYED IN RED WITH A -12, AND THE VSI NOW WAS SHOWING A RED ARC FROM ZERO ON DOWN, AND A GREEN ARC STARTING AT ABOUT 1000 FPM RATE OF CLB. THE CAPT AND I WERE NOT ABLE TO MAKE VIS CONTACT. THE CAPT MEANWHILE HAD ALREADY DISCONNECTED THE AUTOPLT AND STARTED AN IMMEDIATE CLB AND DIRECTED ME TO NOTIFY ATC. THIS WAS ALMOST IMMEDIATELY FOLLOWED BY A 'MONITOR VERT SPD' AND NO RED OR GREEN ARC DISPLAY. I ADVISED APCH THAT WE WERE DEVIATING FOR A TA. IN FACT WE WERE DEVIATING FOR A RA AND I CANNOT RECALL IF I TOLD THEM WE WERE CLBING. BY THE TIME APCH RESPONDED TO CONFIRM MY RADIO XMISSION, WE WERE LEVEL AT 11400'. APCH ADVISED US THAT THE TFC WAS ASSIGNED 10000' (NO MENTION WAS MADE IF HE WAS ACTUALLY AT 10000'). THE CAPT DSNDED BACK TO 11000' AND APCH CTL MADE NO FURTHER COMMENT ABOUT THE INCIDENT. AS AN AFTERTHOUGHT, IF AN ACFT CLBING OR DSNDING TO AN ASSIGNED ALT CAN SET OFF A TCAS RA IN ANOTHER ACFT, IT THEN BECOMES INCUMBENT ON ATC TO ADVISE PLTS IN BOTH VMC AND IMC OF ALT ASSIGNMENTS OF POTENTIAL 'CONFLICT' ACFT (AS IF ATC DOESN'T HAVE ENOUGH TO DO). IN HIGH DENSITY TFC AREAS EQUIPPED WITH A SYS THAT USES VERT ONLY COMMANDS TO RESOLVE TFC CONFLICTS, IT IS NOT TOO DIFFICULT TO ENVISION ONE ACFT COMPLYING WITH A RA BECOMING A RA FOR ANOTHER. MUCH LIKE FALLING DOMINOS.

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.

On approach to dfw at 11000' MSL flight crew of medium large transport received TCAS ii RA and climbed to 11400' before erasing the RA. Traffic was reported at 10000'.