A TRACON controller questions the propriety of an air carrier mdt turning in response to a TCASII al...

Attributes
ACN	259688
Time
Date	199312
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : hfd
State Reference	CT
Altitude	msl bound lower : 6000 msl bound upper : 6400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : lga
Operator	common carrier : air carrier
Make Model Name	Medium Transport, High Wing, 2 Turboprop Eng
Navigation In Use	Other Other
Flight Phase	cruise other descent other
Route In Use	enroute airway : bdl
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 6
ASRS Report	259688
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : clearance non adherence : far non adherence : published procedure other anomaly other other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Air carrier mdt en route ewr on route V229, I issued descent from 8000 ft to 6000 ft and at same time issued traffic 10 O'clock, 8 mi nwbound, altitude unknown. At 6700 ft in descent, I reissued traffic 10 O'clock, 3 mi, nwbound, altitude unknown. Out of 6400 ft the crew notified me they were turning to heading 300 degrees to avoid traffic. I asked if he had traffic in sight and the altitude. He informed me they didn't see the traffic, they were turning based on the TCASII information. I thought this type of maneuver was prohibited with the TCASII program. This is the second time aircraft made lateral move based on TCASII information. Callback conversation with reporter revealed the following: the intruder traffic was a 1200 squawk with no mode C. The reporter was assured that he is correct, aircraft are not supposed to maneuver other than climb or descend in response to a TCASII command.

Original NASA ASRS Text

Title: A TRACON CTLR QUESTIONS THE PROPRIETY OF AN ACR MDT TURNING IN RESPONSE TO A TCASII ALERT.

Narrative: ACR MDT ENRTE EWR ON RTE V229, I ISSUED DSCNT FROM 8000 FT TO 6000 FT AND AT SAME TIME ISSUED TFC 10 O'CLOCK, 8 MI NWBOUND, ALT UNKNOWN. AT 6700 FT IN DSCNT, I REISSUED TFC 10 O'CLOCK, 3 MI, NWBOUND, ALT UNKNOWN. OUT OF 6400 FT THE CREW NOTIFIED ME THEY WERE TURNING TO HDG 300 DEGS TO AVOID TFC. I ASKED IF HE HAD TFC IN SIGHT AND THE ALT. HE INFORMED ME THEY DIDN'T SEE THE TFC, THEY WERE TURNING BASED ON THE TCASII INFO. I THOUGHT THIS TYPE OF MANEUVER WAS PROHIBITED WITH THE TCASII PROGRAM. THIS IS THE SECOND TIME ACFT MADE LATERAL MOVE BASED ON TCASII INFO. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: THE INTRUDER TFC WAS A 1200 SQUAWK WITH NO MODE C. THE RPTR WAS ASSURED THAT HE IS CORRECT, ACFT ARE NOT SUPPOSED TO MANEUVER OTHER THAN CLB OR DSND IN RESPONSE TO A TCASII COMMAND.

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.

A TRACON controller questions the propriety of an air carrier mdt turning in response to a TCASII alert.