Pilot looks for reported traffic and deviates from assigned altitude.

Attributes
ACN	448295
Time
Date	199909
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : hfd.airport
State Reference	CT
Altitude	msl bound lower : 3600 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : y90.tracon
Operator	general aviation : personal
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	cruise : level
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : y90.tracon
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Experience	flight time last 90 days : 100 flight time total : 2050 flight time type : 550
ASRS Report	448295
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance
Independent Detector	atc equipment other atc equipment : radar other controllera other flight crewa
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I received a call from bdl approach about traffic with 'no altitude' in front of me. I also saw the traffic on my skywatch system (also with no altitude block). The traffic became a threat in my opinion and bdl approach continued to have no altitude. I disengaged the autoplt to allow me to maneuver more easily. I couldn't see traffic, despite threat, so I pushed over nose to look below. In the process of searching below (I thought most likely if traffic with no altitude), I momentarily descended to 3600 ft. ATC advised me of this. I explained that I was searching for traffic and immediately returned to 4000 ft. ATC said 'no problem.' I continued without further event. I was concerned that I deviated from my altitude momentarily while maneuvering for traffic.

Original NASA ASRS Text

Title: PLT LOOKS FOR RPTED TFC AND DEVIATES FROM ASSIGNED ALT.

Narrative: I RECEIVED A CALL FROM BDL APCH ABOUT TFC WITH 'NO ALT' IN FRONT OF ME. I ALSO SAW THE TFC ON MY SKYWATCH SYS (ALSO WITH NO ALT BLOCK). THE TFC BECAME A THREAT IN MY OPINION AND BDL APCH CONTINUED TO HAVE NO ALT. I DISENGAGED THE AUTOPLT TO ALLOW ME TO MANEUVER MORE EASILY. I COULDN'T SEE TFC, DESPITE THREAT, SO I PUSHED OVER NOSE TO LOOK BELOW. IN THE PROCESS OF SEARCHING BELOW (I THOUGHT MOST LIKELY IF TFC WITH NO ALT), I MOMENTARILY DSNDED TO 3600 FT. ATC ADVISED ME OF THIS. I EXPLAINED THAT I WAS SEARCHING FOR TFC AND IMMEDIATELY RETURNED TO 4000 FT. ATC SAID 'NO PROB.' I CONTINUED WITHOUT FURTHER EVENT. I WAS CONCERNED THAT I DEVIATED FROM MY ALT MOMENTARILY WHILE MANEUVERING FOR TFC.

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.