Air carrier large transport altitude deviation excursion from clearance altitude in response to TCAS...

Attributes
ACN	190099
Time
Date	199109
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ptw airport : phl
State Reference	PA
Altitude	msl bound lower : 10000 msl bound upper : 10500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : gum
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute airway : zny
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	descent other
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 5000 flight time type : 700
ASRS Report	190099
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance
Consequence	Other
Miss Distance	horizontal : 6000 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

We were level at 10000 ft. The controller called out traffic at 12 O'clock. TCASII indicated 2 targets and we could see both in front of us. The TCASII issued an RA on the nearer target, it was a small light aircraft in a rapid descent, crossing our nose from left to right and coming towards us. Since I could see the aircraft visually and I didn't perceive it as a threat, a delayed complying with the TCASII RA. We tried to inform the controller of the situation but he was very busy on the radio and we couldn't get a word in. We then initiated a climb without ATC clearance to comply with the TCASII RA. As soon as possible we advised the controller of our actions and he cleared us to 11000 ft. Remedy: reduce the controller's workload so he can better control the traffic in his sector.

Original NASA ASRS Text

Title: ACR LGT ALTDEV EXCURSION FROM CLRNC ALT IN RESPONSE TO TCASII RA.

Narrative: WE WERE LEVEL AT 10000 FT. THE CTLR CALLED OUT TFC AT 12 O'CLOCK. TCASII INDICATED 2 TARGETS AND WE COULD SEE BOTH IN FRONT OF US. THE TCASII ISSUED AN RA ON THE NEARER TARGET, IT WAS A SMALL LIGHT ACFT IN A RAPID DSCNT, XING OUR NOSE FROM L TO R AND COMING TOWARDS US. SINCE I COULD SEE THE ACFT VISUALLY AND I DIDN'T PERCEIVE IT AS A THREAT, A DELAYED COMPLYING WITH THE TCASII RA. WE TRIED TO INFORM THE CTLR OF THE SITUATION BUT HE WAS VERY BUSY ON THE RADIO AND WE COULDN'T GET A WORD IN. WE THEN INITIATED A CLB WITHOUT ATC CLRNC TO COMPLY WITH THE TCASII RA. AS SOON AS POSSIBLE WE ADVISED THE CTLR OF OUR ACTIONS AND HE CLRED US TO 11000 FT. REMEDY: REDUCE THE CTLR'S WORKLOAD SO HE CAN BETTER CTL THE TFC IN HIS SECTOR.

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.

Air carrier large transport altitude deviation excursion from clearance altitude in response to TCASII RA.