Flight crew of an mdt air carrier aircraft descended below assigned altitude in response to a TCASII...

Attributes
ACN	255607
Time
Date	199310
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mad
State Reference	CT
Altitude	msl bound lower : 8600 msl bound upper : 9000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Transport, High Wing, 2 Turboprop Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute airway : n90
Flight Plan	IFR
Aircraft 2
Operator	other
Make Model Name	Fighter
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 6500 flight time type : 4300
ASRS Report	255607
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 230 flight time total : 6500 flight time type : 1600
ASRS Report	256489
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 0 vertical : 2000
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Scheduled flight from jfk to bos at 9000 ft over mad VOR. Crew received a descend command from the TCASII. First officer (PF) disengaged the autoplt and started a descent. About 5 seconds later increased descent from the TCASII. At approximately 8600 ft was accomplished before 'monitor vertical speed' command was received. As first officer initiated leveloff and climb back to altitude, PNF informed ATC controller of deviation. 2 fgt's were seen passing northbound directly above aircraft. ATC controller indicated that the fgt's were at 11000 ft as they came into view.

Original NASA ASRS Text

Title: FLC OF AN MDT ACR ACFT DSNDED BELOW ASSIGNED ALT IN RESPONSE TO A TCASII RA.

Narrative: SCHEDULED FLT FROM JFK TO BOS AT 9000 FT OVER MAD VOR. CREW RECEIVED A DSND COMMAND FROM THE TCASII. FO (PF) DISENGAGED THE AUTOPLT AND STARTED A DSCNT. ABOUT 5 SECONDS LATER INCREASED DSCNT FROM THE TCASII. AT APPROX 8600 FT WAS ACCOMPLISHED BEFORE 'MONITOR VERT SPD' COMMAND WAS RECEIVED. AS FO INITIATED LEVELOFF AND CLB BACK TO ALT, PNF INFORMED ATC CTLR OF DEV. 2 FGT'S WERE SEEN PASSING NBOUND DIRECTLY ABOVE ACFT. ATC CTLR INDICATED THAT THE FGT'S WERE AT 11000 FT AS THEY CAME INTO VIEW.

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 an mdt air carrier aircraft descended below assigned altitude in response to a TCASII RA.