Altitude deviation.

Attributes
ACN	206383
Time
Date	199203
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : alb
State Reference	NY
Altitude	msl bound lower : 24000 msl bound upper : 24400
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zbw tower : vny
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 175 flight time total : 18500 flight time type : 1500
ASRS Report	206383
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 15000 vertical : 1400
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

My flight was level at 240 -- a TCASII TA was received and almost immediately followed by a TCASII RA 'climb -- climb.' the intruder aircraft was not in sight so I initiated a climb and advised ZBW we were deviating from FL240 for a TCASII RA. I climbed 300-400 ft and the first officer called the traffic in sight. At that time we descended back to 240. This was probably a clear case of the TCASII equipment not knowing the intent of the intruder aircraft to level at 230. However, since the aircraft was not in sight visually, I followed the TCASII RA climb command maximum deviation from altitude was about 400 ft and the entire incident happened over 10-20 seconds.

Original NASA ASRS Text

Title: ALTDEV.

Narrative: MY FLT WAS LEVEL AT 240 -- A TCASII TA WAS RECEIVED AND ALMOST IMMEDIATELY FOLLOWED BY A TCASII RA 'CLB -- CLB.' THE INTRUDER ACFT WAS NOT IN SIGHT SO I INITIATED A CLB AND ADVISED ZBW WE WERE DEVIATING FROM FL240 FOR A TCASII RA. I CLBED 300-400 FT AND THE FO CALLED THE TFC IN SIGHT. AT THAT TIME WE DSNDED BACK TO 240. THIS WAS PROBABLY A CLR CASE OF THE TCASII EQUIP NOT KNOWING THE INTENT OF THE INTRUDER ACFT TO LEVEL AT 230. HOWEVER, SINCE THE ACFT WAS NOT IN SIGHT VISUALLY, I FOLLOWED THE TCASII RA CLB COMMAND MAX DEV FROM ALT WAS ABOUT 400 FT AND THE ENTIRE INCIDENT HAPPENED OVER 10-20 SECONDS.

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.