TRACON controller described an altitude excursion causing an loss of separation; the aircraft in que...

Attributes
ACN	973504
Time
Date	201110
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Aircraft 1
Make Model Name	Citation II S2/Bravo (C550)
Flight Phase	Climb
Flight Plan	IFR
Person 1
Function	Approach Departure
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Captain
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Commercial
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Overshoot Deviation - Procedural Clearance

Narrative:

Aircraft X departed northwest bound; IFR; and was instructed to climb and maintain 3000 feet. I issued traffic to aircraft X on aircraft Y; southwest bound level at 4000 feet; IFR; 6 miles northeast. I observed aircraft X altitude climb to 3300 feet. I instructed aircraft X to maintain 3000 feet and issued traffic again on the aircraft Y; who was still level at 4000 feet southwest bound. When aircraft X replied; and advised he was correcting; the altitude indicated 3400 feet. Aircraft Y passed behind aircraft X; and as I advised aircraft X that traffic was no longer a factor; I observed aircraft X in a decent back to 3000 feet.

Original NASA ASRS Text

Title: TRACON Controller described an altitude excursion causing an loss of separation; the aircraft in questions reported equipment problems as the primary contributing factor.

Narrative: Aircraft X departed Northwest bound; IFR; and was instructed to climb and maintain 3000 feet. I issued traffic to Aircraft X on Aircraft Y; Southwest bound level at 4000 feet; IFR; 6 miles Northeast. I observed Aircraft X altitude climb to 3300 feet. I instructed Aircraft X to maintain 3000 feet and issued traffic again on the Aircraft Y; who was still level at 4000 feet Southwest bound. When Aircraft X replied; and advised he was correcting; the altitude indicated 3400 feet. Aircraft Y passed behind Aircraft X; and as I advised Aircraft X that traffic was no longer a factor; I observed Aircraft X in a decent back to 3000 feet.

Data retrieved from NASA's ASRS site as of April 2012 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.

TRACON controller described an altitude excursion causing an loss of separation; the aircraft in questions reported equipment problems as the primary contributing factor.