Air carrier change of altitude without clearance.

Attributes
ACN	108494
Time
Date	198904
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : elm
State Reference	NY
Altitude	msl bound lower : 20000 msl bound upper : 22000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
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 : 210 flight time total : 30000 flight time type : 5600
ASRS Report	108494
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

En route ewr-buf, ny issued descent to the usual 22000' into cle area. Changed to cle 133.35 and checked in, vicinity of elm. Cle talked to nearby traffic at 21000' giving us as traffic (5 mi or more). Cleared us to 20000'. We read back, wrote it down, entered in reminder. We descended after we arrived at 20000'. Cle asked our altitude. Reported 20000'. No conflict with other traffic, ATC advised, but denied giving us clearance. I believe a trnee was on ATC, with supervisor at station. We may have heard a transmission that wasn't meant to be broadcast or should have been to the next sector, but we definitely received clearance by airline and flight # to descend to 20000' which we read back. Traffic was very light. Maybe one other airplane being directed. I had a very qualified first officer who heard and responded exactly as I did, verifying my recall. After ATC advised he had not assigned 20000' I asked 3 times what assignment they had to solve the problem. Was advised there was no conflict, but still did not get an assignment that seemed appropriate. We will have mistakes in our systems. We must accept that and be prepared to prevent compounding the problem by letting a mistake throw us off our intended purpose or disrupting things too much. Imagination solves problems, not amazement. Thank you.

Original NASA ASRS Text

Title: ACR CHANGE OF ALT WITHOUT CLRNC.

Narrative: ENRTE EWR-BUF, NY ISSUED DSCNT TO THE USUAL 22000' INTO CLE AREA. CHANGED TO CLE 133.35 AND CHKED IN, VICINITY OF ELM. CLE TALKED TO NEARBY TFC AT 21000' GIVING US AS TFC (5 MI OR MORE). CLRED US TO 20000'. WE READ BACK, WROTE IT DOWN, ENTERED IN REMINDER. WE DSNDED AFTER WE ARRIVED AT 20000'. CLE ASKED OUR ALT. RPTED 20000'. NO CONFLICT WITH OTHER TFC, ATC ADVISED, BUT DENIED GIVING US CLRNC. I BELIEVE A TRNEE WAS ON ATC, WITH SUPVR AT STATION. WE MAY HAVE HEARD A XMISSION THAT WASN'T MEANT TO BE BROADCAST OR SHOULD HAVE BEEN TO THE NEXT SECTOR, BUT WE DEFINITELY RECEIVED CLRNC BY AIRLINE AND FLT # TO DSND TO 20000' WHICH WE READ BACK. TFC WAS VERY LIGHT. MAYBE ONE OTHER AIRPLANE BEING DIRECTED. I HAD A VERY QUALIFIED F/O WHO HEARD AND RESPONDED EXACTLY AS I DID, VERIFYING MY RECALL. AFTER ATC ADVISED HE HAD NOT ASSIGNED 20000' I ASKED 3 TIMES WHAT ASSIGNMENT THEY HAD TO SOLVE THE PROB. WAS ADVISED THERE WAS NO CONFLICT, BUT STILL DID NOT GET AN ASSIGNMENT THAT SEEMED APPROPRIATE. WE WILL HAVE MISTAKES IN OUR SYSTEMS. WE MUST ACCEPT THAT AND BE PREPARED TO PREVENT COMPOUNDING THE PROB BY LETTING A MISTAKE THROW US OFF OUR INTENDED PURPOSE OR DISRUPTING THINGS TOO MUCH. IMAGINATION SOLVES PROBS, NOT AMAZEMENT. THANK YOU.

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.