Unauthorized climb to occupied altitude resulting in less than standard separation. Pilot deviation.

Attributes
ACN	118859
Time
Date	198908
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : bgm
State Reference	NY
Altitude	msl bound lower : 9000 msl bound upper : 10000
Environment
Light	Night
Aircraft 1
Controlling Facilities	tracon : bgm
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct enroute airway : zny
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 1
ASRS Report	118859
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated
Miss Distance	vertical : 600
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Aircraft cleared off of bgm approach to 9000'. Aircraft checked on the frequency climbing to 10,000'. As radar controller, I thought I heard the pilot saying he was climbing to 9000'. Subsequently a loss of separation occurred when this aircraft broke through nine for ten thousand feet. I immediately descended the aircraft back down to nine thousand feet to regain separation. Somewhere along the line the pilot thought he was assigned ten thousand feet. Neither approach control nor center ATC cleared the aircraft to ten thousand feet.

Original NASA ASRS Text

Title: UNAUTH CLIMB TO OCCUPIED ALT RESULTING IN LESS THAN STANDARD SEPARATION. PLT DEVIATION.

Narrative: ACFT CLRED OFF OF BGM APCH TO 9000'. ACFT CHECKED ON THE FREQ CLIMBING TO 10,000'. AS RADAR CTLR, I THOUGHT I HEARD THE PLT SAYING HE WAS CLIMBING TO 9000'. SUBSEQUENTLY A LOSS OF SEPARATION OCCURRED WHEN THIS ACFT BROKE THROUGH NINE FOR TEN THOUSAND FEET. I IMMEDIATELY DESCENDED THE ACFT BACK DOWN TO NINE THOUSAND FEET TO REGAIN SEPARATION. SOMEWHERE ALONG THE LINE THE PLT THOUGHT HE WAS ASSIGNED TEN THOUSAND FEET. NEITHER APCH CTL NOR CENTER ATC CLRED THE ACFT TO TEN THOUSAND FEET.

Data retrieved from NASA's ASRS site as of August 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.