Flight crew of air carrier large transport aircraft deviation from assigned altitude in response to ...

Attributes
ACN	218241
Time
Date	199208
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : bos
State Reference	MA
Altitude	msl bound lower : 4500 msl bound upper : 5400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : bos
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach descent other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	climbout : intermediate altitude
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 200 flight time total : 9500 flight time type : 750
ASRS Report	218241
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 0 vertical : 300
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Bos approach advised us of traffic at 4500 ft and 2 mi 11 O'clock had us in sight. Several targets were noted on TCASII but no positive on our part. Several moments later, we saw the aircraft passing under our nose, it looked very close and had 'TCASII' alert climb oral message as well as vertical climb command on vvi. TCASII indicated traffic was under us on collision course climbing through 4700 ft. We made a slight left turn and climbed 400 ft to 5400 ft. This silenced the TCASII alert. We advised ATC. His response was 'if it was our company policy to deviate for this type of alert if we were advised by ATC of location of traffic, that 'they' had had us in sight?' we advised her that it was. We felt the action was necessary to avoid a collision. Recommend that ATC not allow climbing aircraft only 500 ft separation and vertical should be 1000 ft or more because of possible cockpit distrs during climb.

Original NASA ASRS Text

Title: FLC OF ACR LGT ACFT DEV FROM ASSIGNED ALT IN RESPONSE TO A TCASII RA.

Narrative: BOS APCH ADVISED US OF TFC AT 4500 FT AND 2 MI 11 O'CLOCK HAD US IN SIGHT. SEVERAL TARGETS WERE NOTED ON TCASII BUT NO POSITIVE ON OUR PART. SEVERAL MOMENTS LATER, WE SAW THE ACFT PASSING UNDER OUR NOSE, IT LOOKED VERY CLOSE AND HAD 'TCASII' ALERT CLB ORAL MESSAGE AS WELL AS VERT CLB COMMAND ON VVI. TCASII INDICATED TFC WAS UNDER US ON COLLISION COURSE CLBING THROUGH 4700 FT. WE MADE A SLIGHT L TURN AND CLBED 400 FT TO 5400 FT. THIS SILENCED THE TCASII ALERT. WE ADVISED ATC. HIS RESPONSE WAS 'IF IT WAS OUR COMPANY POLICY TO DEVIATE FOR THIS TYPE OF ALERT IF WE WERE ADVISED BY ATC OF LOCATION OF TFC, THAT 'THEY' HAD HAD US IN SIGHT?' WE ADVISED HER THAT IT WAS. WE FELT THE ACTION WAS NECESSARY TO AVOID A COLLISION. RECOMMEND THAT ATC NOT ALLOW CLBING ACFT ONLY 500 FT SEPARATION AND VERT SHOULD BE 1000 FT OR MORE BECAUSE OF POSSIBLE COCKPIT DISTRS DURING CLB.

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.

Flight crew of air carrier large transport aircraft deviation from assigned altitude in response to a TCASII RA.