Altitude deviation altitude excursion from assigned. BE02 PIC answered clearance given to other airc...

Attributes
ACN	362071
Time
Date	199702
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : omn
State Reference	FL
Altitude	msl bound lower : 20500 msl bound upper : 21000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx
Operator	common carrier : air carrier
Make Model Name	Beech 1900
Operating Under FAR Part	Part 91
Navigation In Use	Other
Flight Phase	cruise other descent other
Route In Use	enroute other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Flight Phase	cruise other descent 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 : 225 flight time total : 7000 flight time type : 100
ASRS Report	362071
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 : published procedure non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Deviation Pilot Deviation

Narrative:

While cruising at FL220, ZJX issued a descent clearance to FL210. Before reaching FL210, I acknowledged a clearance to cross vrb at 10000 ft, expect the stoop intersection at 6000 ft. The controller did not issue an altimeter setting with this new clearance. I immediately asked for one. Descending through 20500 ft the controller asked my altitude. I reported a descent through 20500 ft for 10000 ft. According to the controller I was supposed to be at FL210. Upon landing at the destination (sua) I was instructed to contact ZJX supervisor. The subsequent review of the ATC tape revealed that myself and another aircraft read back the descent clearance at the same time, thus creating a 'squeel' over the controller's audio. The controller never verified which aircraft acknowledged the blocked clearance. The tape also revealed that the other aircraft unkeyed his microphone first, allowing the last 2 digits in my call sign to be heard, 'xy.' according to the supervisor, I read back a clearance for another aircraft. Also, the clearance acknowledged by myself was a relevant one, the same I would have received. After further review of the ATC tape, the supervisor advised me specifically that no pilot deviation had taken place and that this was being classified as an ATC operational error. Contributing factors include: 1) non compliance with established ATC procedures, 2) a busy ATC frequency, 3) the descent phase of flight.

Original NASA ASRS Text

Title: ALTDEV ALT EXCURSION FROM ASSIGNED. BE02 PIC ANSWERED CLRNC GIVEN TO OTHER ACFT.

Narrative: WHILE CRUISING AT FL220, ZJX ISSUED A DSCNT CLRNC TO FL210. BEFORE REACHING FL210, I ACKNOWLEDGED A CLRNC TO CROSS VRB AT 10000 FT, EXPECT THE STOOP INTXN AT 6000 FT. THE CTLR DID NOT ISSUE AN ALTIMETER SETTING WITH THIS NEW CLRNC. I IMMEDIATELY ASKED FOR ONE. DSNDING THROUGH 20500 FT THE CTLR ASKED MY ALT. I RPTED A DSCNT THROUGH 20500 FT FOR 10000 FT. ACCORDING TO THE CTLR I WAS SUPPOSED TO BE AT FL210. UPON LNDG AT THE DEST (SUA) I WAS INSTRUCTED TO CONTACT ZJX SUPVR. THE SUBSEQUENT REVIEW OF THE ATC TAPE REVEALED THAT MYSELF AND ANOTHER ACFT READ BACK THE DSCNT CLRNC AT THE SAME TIME, THUS CREATING A 'SQUEEL' OVER THE CTLR'S AUDIO. THE CTLR NEVER VERIFIED WHICH ACFT ACKNOWLEDGED THE BLOCKED CLRNC. THE TAPE ALSO REVEALED THAT THE OTHER ACFT UNKEYED HIS MIKE FIRST, ALLOWING THE LAST 2 DIGITS IN MY CALL SIGN TO BE HEARD, 'XY.' ACCORDING TO THE SUPVR, I READ BACK A CLRNC FOR ANOTHER ACFT. ALSO, THE CLRNC ACKNOWLEDGED BY MYSELF WAS A RELEVANT ONE, THE SAME I WOULD HAVE RECEIVED. AFTER FURTHER REVIEW OF THE ATC TAPE, THE SUPVR ADVISED ME SPECIFICALLY THAT NO PLTDEV HAD TAKEN PLACE AND THAT THIS WAS BEING CLASSIFIED AS AN ATC OPERROR. CONTRIBUTING FACTORS INCLUDE: 1) NON COMPLIANCE WITH ESTABLISHED ATC PROCS, 2) A BUSY ATC FREQ, 3) THE DSCNT PHASE OF FLT.

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.

Altitude deviation altitude excursion from assigned. BE02 PIC answered clearance given to other aircraft.