Twin engine turboprop light transport lost 400 ft while looking for traffic.

Attributes
ACN	366750
Time
Date	199704
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : cll
State Reference	TX
Altitude	msl bound lower : 3600 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zhu
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 6500 flight time type : 1500
ASRS Report	366750
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Was asked to slow 40 DME from cll to allow a T37 to land in front of us. The air traffic controller seemed agitated that we called this traffic in sight. As we neared the airport I lost approximately 400 ft as I searched for the aircraft to follow. No conflict arose. When the controller mentioned 4000 ft I realized I had deviated and returned to my altitude.

Original NASA ASRS Text

Title: TWIN ENG TURBOPROP LTT LOST 400 FT WHILE LOOKING FOR TFC.

Narrative: WAS ASKED TO SLOW 40 DME FROM CLL TO ALLOW A T37 TO LAND IN FRONT OF US. THE AIR TFC CTLR SEEMED AGITATED THAT WE CALLED THIS TFC IN SIGHT. AS WE NEARED THE ARPT I LOST APPROX 400 FT AS I SEARCHED FOR THE ACFT TO FOLLOW. NO CONFLICT AROSE. WHEN THE CTLR MENTIONED 4000 FT I REALIZED I HAD DEVIATED AND RETURNED TO MY ALT.

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.