C550 flight depart assigned altitude after assuming ZOB transmission was for them.

Attributes
ACN	500520
Time
Date	200102
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : lan.vor
State Reference	MI
Altitude	msl bound lower : 25000 msl bound upper : 27000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob.artcc
Operator	general aviation : corporate
Make Model Name	Citation II S2/Bravo
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	cruise : enroute altitude change
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : coordinator
Qualification	pilot : cfi pilot : atp pilot : multi engine
Experience	flight time last 90 days : 60 flight time total : 17000 flight time type : 4000
ASRS Report	500520
Person 2
Affiliation	company : corporate
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : multi engine
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	atc equipment other atc equipment : radar other controllera
Resolutory Action	controller : issued advisory controller : issued new clearance
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I filed a flight plan from grr to ilg. I filed for FL330. Received my clearance (maintain 4000 ft, expect FL330 10 mins after departure). Started out on flight and was leveled several times prior to cruise altitude. At the time of the altitude bust, I was just checking on with the next controller as 'citation with you climbing to FL250 (or level FL250) -- I honestly don't remember which one it was. ATC answered right away saying 'roger, FL250' -- 1 or 2 microphone clicks followed immediately by 'climb and maintain FL330' (my filed, expected and appropriate time frame for expecting to receive those instructions). I answered immediately, 'roger, climb and maintain FL330.' I reset my altitude alerter, checked my TCASII and initiated a 2000 FPM climb towards FL330, power up. There was no other aircraft I could hear responding to the clearance and the frequency was quiet. At approximately FL270, ATC came on and said 'I show you climbing through FL270, maintain FL270, you were only cleared to FL250.' I leveled off at FL270 and said 'I thought you cleared me to FL330.' there was no answer and no further dialog concerning it, between me and the controller. I was switched a short time later to the next cleveland controller and went on with the flight. I think it was a classic case of 2 planes blocking the frequency simultaneously -- twice!

Original NASA ASRS Text

Title: C550 FLT DEPART ASSIGNED ALT AFTER ASSUMING ZOB TRANSMISSION WAS FOR THEM.

Narrative: I FILED A FLT PLAN FROM GRR TO ILG. I FILED FOR FL330. RECEIVED MY CLRNC (MAINTAIN 4000 FT, EXPECT FL330 10 MINS AFTER DEP). STARTED OUT ON FLT AND WAS LEVELED SEVERAL TIMES PRIOR TO CRUISE ALT. AT THE TIME OF THE ALT BUST, I WAS JUST CHKING ON WITH THE NEXT CTLR AS 'CITATION WITH YOU CLBING TO FL250 (OR LEVEL FL250) -- I HONESTLY DON'T REMEMBER WHICH ONE IT WAS. ATC ANSWERED RIGHT AWAY SAYING 'ROGER, FL250' -- 1 OR 2 MIKE CLICKS FOLLOWED IMMEDIATELY BY 'CLB AND MAINTAIN FL330' (MY FILED, EXPECTED AND APPROPRIATE TIME FRAME FOR EXPECTING TO RECEIVE THOSE INSTRUCTIONS). I ANSWERED IMMEDIATELY, 'ROGER, CLB AND MAINTAIN FL330.' I RESET MY ALT ALERTER, CHKED MY TCASII AND INITIATED A 2000 FPM CLB TOWARDS FL330, PWR UP. THERE WAS NO OTHER ACFT I COULD HEAR RESPONDING TO THE CLRNC AND THE FREQ WAS QUIET. AT APPROX FL270, ATC CAME ON AND SAID 'I SHOW YOU CLBING THROUGH FL270, MAINTAIN FL270, YOU WERE ONLY CLRED TO FL250.' I LEVELED OFF AT FL270 AND SAID 'I THOUGHT YOU CLRED ME TO FL330.' THERE WAS NO ANSWER AND NO FURTHER DIALOG CONCERNING IT, BTWN ME AND THE CTLR. I WAS SWITCHED A SHORT TIME LATER TO THE NEXT CLEVELAND CTLR AND WENT ON WITH THE FLT. I THINK IT WAS A CLASSIC CASE OF 2 PLANES BLOCKING THE FREQ SIMULTANEOUSLY -- TWICE!

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.