Narrative:

Air carrier X was in a holding pattern at cetus intersection (djb 310 degrees/36) and cleared to continue descent to 14000'. Due to deteriorating WX at cetus, air carrier X was reclred to sandusky VOR and instructed to hold west on V6. Approaching sandusky VOR we received xmissions re: lightning strikes at detroit metropolitan airport and the company ramp control tower being evacked due to a tornado. Our fuel was approaching the point where we were making the divert to grand rapids, our landing alternate. This was the point in time when we entered holding at sandusky. With numerous aircraft entering holding patterns, diverting to alternates, the uncertain status of the company ramp operation, the fuel situation on air carrier X and the considerable congestion on ZOB frequency as well as the workload on our #2 radio, the cockpit in air carrier X was very busy! We believed we had a clearance to 10000', as that altitude was indicated on my scratchpad and set in the altitude alerter. Consequently I reported entering the hold at sandusky and reported 14000 for 10000' and then began a descent after a female controller's voice responded, 'air carrier X, roger.' an air carrier Z flight also in the pattern at 12000' queried ZOB about our descent. At that time, air carrier X queried ATC if we were cleared to 10000' and ATC responded 'negative,' at which time we immediately initiated a climb from 13600 back to 14000'. Shortly thereafter, air carrier X departed to our landing alternate at grand rapids, and en route, ZOB advised us to contact them re: the incident. Callback conversation with reporter revealed the following: reporter was contacted about his callback to ATC supervisor about altitude deviation. Reporter stated there were several company aircraft on the frequency, some with similar a/north. The ARTCC supervisor informed the reporter an altitude deviation violation was going to be processed because the tape playback did not show any altitude change issued to air carrier X. Analyst suspects air carrier heard clearance for another company aircraft. Reporter stated he was not informed he conflicted with another aircraft. Analyst suspects less than standard separation with an aircraft holding at 13000'. Error detection program computer detected error. ATC supervisor second call to reporter indicated that the reporter reported with callsign leaving 14000 for 10000', and the controller acknowledged with air carrier X call sign. ATC supervisor stated that an operational error was being filed against the controller and a pilot deviation because air carrier X was never issued a descent clearance. Supplemental information from acn 156079: flight specifics: air carrier X from norfolk to detroit, detroit WX was severe thunderstorms and low visibility. Contributing factors: 1) hazardous WX, severe thunderstorms throughout the area, heavy turbulence, rain and lightning. 2) heavy radio chatter, numerous aircraft in holding, call signs were being cutoff, lots of requests for different airspace. 3) our fuel state was rapidly approaching divert level. 4) human factors: stress, fatigue, frustration brought on by WX delays. The captain was trying to talk to our company and both radios were jammed up. We heard a clearance to 10000' that we thought was for us. The captain called air carrier X descending from 14000 to 10000', and we got an 'air carrier X, roger,' and I began a slow descent. An air carrier Z in the pattern below us at 12000' asked center if she had cleared us through their altitude. She said negative. I immediately asked if we were cleared to 10000'. She said negative. So I started an abrupt climb from 13600' back to 14000'. Total time away form 14000' was approximately 30-40 seconds. Corrective action: none required. A minor mistake was made--ours and the controllers--and we took positive and professional corrective action immediately to fix the problem. Factors affecting human performance: to the above human factors add fear. With lightning whirling around the aircraft and thunder so loud it could block out radio xmissions, yes I was little scared. I wish I was as perfect and as fearless as the ATC computer.

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Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION WITH ACFT Y. SYSTEM ERROR. ACR X UNAUTH ALT CHANGE. PLT DEVIATION.

Narrative: ACR X WAS IN A HOLDING PATTERN AT CETUS INTXN (DJB 310 DEGS/36) AND CLRED TO CONTINUE DSNT TO 14000'. DUE TO DETERIORATING WX AT CETUS, ACR X WAS RECLRED TO SANDUSKY VOR AND INSTRUCTED TO HOLD W ON V6. APCHING SANDUSKY VOR WE RECEIVED XMISSIONS RE: LIGHTNING STRIKES AT DETROIT METRO ARPT AND THE COMPANY RAMP CTL TWR BEING EVACKED DUE TO A TORNADO. OUR FUEL WAS APCHING THE POINT WHERE WE WERE MAKING THE DIVERT TO GRAND RAPIDS, OUR LNDG ALTERNATE. THIS WAS THE POINT IN TIME WHEN WE ENTERED HOLDING AT SANDUSKY. WITH NUMEROUS ACFT ENTERING HOLDING PATTERNS, DIVERTING TO ALTERNATES, THE UNCERTAIN STATUS OF THE COMPANY RAMP OPERATION, THE FUEL SITUATION ON ACR X AND THE CONSIDERABLE CONGESTION ON ZOB FREQ AS WELL AS THE WORKLOAD ON OUR #2 RADIO, THE COCKPIT IN ACR X WAS VERY BUSY! WE BELIEVED WE HAD A CLRNC TO 10000', AS THAT ALT WAS INDICATED ON MY SCRATCHPAD AND SET IN THE ALT ALERTER. CONSEQUENTLY I RPTED ENTERING THE HOLD AT SANDUSKY AND RPTED 14000 FOR 10000' AND THEN BEGAN A DSNT AFTER A FEMALE CTLR'S VOICE RESPONDED, 'ACR X, ROGER.' AN ACR Z FLT ALSO IN THE PATTERN AT 12000' QUERIED ZOB ABOUT OUR DSNT. AT THAT TIME, ACR X QUERIED ATC IF WE WERE CLRED TO 10000' AND ATC RESPONDED 'NEGATIVE,' AT WHICH TIME WE IMMEDIATELY INITIATED A CLB FROM 13600 BACK TO 14000'. SHORTLY THEREAFTER, ACR X DEPARTED TO OUR LNDG ALTERNATE AT GRAND RAPIDS, AND ENRTE, ZOB ADVISED US TO CONTACT THEM RE: THE INCIDENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR WAS CONTACTED ABOUT HIS CALLBACK TO ATC SUPVR ABOUT ALT DEVIATION. RPTR STATED THERE WERE SEVERAL COMPANY ACFT ON THE FREQ, SOME WITH SIMILAR A/N. THE ARTCC SUPVR INFORMED THE RPTR AN ALT DEVIATION VIOLATION WAS GOING TO BE PROCESSED BECAUSE THE TAPE PLAYBACK DID NOT SHOW ANY ALT CHANGE ISSUED TO ACR X. ANALYST SUSPECTS ACR HEARD CLRNC FOR ANOTHER COMPANY ACFT. RPTR STATED HE WAS NOT INFORMED HE CONFLICTED WITH ANOTHER ACFT. ANALYST SUSPECTS LESS THAN STANDARD SEPARATION WITH AN ACFT HOLDING AT 13000'. ERROR DETECTION PROGRAM COMPUTER DETECTED ERROR. ATC SUPVR SECOND CALL TO RPTR INDICATED THAT THE RPTR RPTED WITH CALLSIGN LEAVING 14000 FOR 10000', AND THE CTLR ACKNOWLEDGED WITH ACR X CALL SIGN. ATC SUPVR STATED THAT AN OPERROR WAS BEING FILED AGAINST THE CTLR AND A PLT DEVIATION BECAUSE ACR X WAS NEVER ISSUED A DSNT CLRNC. SUPPLEMENTAL INFO FROM ACN 156079: FLT SPECIFICS: ACR X FROM NORFOLK TO DETROIT, DETROIT WX WAS SEVERE TSTMS AND LOW VISIBILITY. CONTRIBUTING FACTORS: 1) HAZARDOUS WX, SEVERE TSTMS THROUGHOUT THE AREA, HVY TURB, RAIN AND LIGHTNING. 2) HVY RADIO CHATTER, NUMEROUS ACFT IN HOLDING, CALL SIGNS WERE BEING CUTOFF, LOTS OF REQUESTS FOR DIFFERENT AIRSPACE. 3) OUR FUEL STATE WAS RAPIDLY APCHING DIVERT LEVEL. 4) HUMAN FACTORS: STRESS, FATIGUE, FRUSTRATION BROUGHT ON BY WX DELAYS. THE CAPT WAS TRYING TO TALK TO OUR COMPANY AND BOTH RADIOS WERE JAMMED UP. WE HEARD A CLRNC TO 10000' THAT WE THOUGHT WAS FOR US. THE CAPT CALLED ACR X DSNDING FROM 14000 TO 10000', AND WE GOT AN 'ACR X, ROGER,' AND I BEGAN A SLOW DSNT. AN ACR Z IN THE PATTERN BELOW US AT 12000' ASKED CENTER IF SHE HAD CLRED US THROUGH THEIR ALT. SHE SAID NEGATIVE. I IMMEDIATELY ASKED IF WE WERE CLRED TO 10000'. SHE SAID NEGATIVE. SO I STARTED AN ABRUPT CLB FROM 13600' BACK TO 14000'. TOTAL TIME AWAY FORM 14000' WAS APPROX 30-40 SECS. CORRECTIVE ACTION: NONE REQUIRED. A MINOR MISTAKE WAS MADE--OURS AND THE CTLRS--AND WE TOOK POSITIVE AND PROFESSIONAL CORRECTIVE ACTION IMMEDIATELY TO FIX THE PROB. FACTORS AFFECTING HUMAN PERFORMANCE: TO THE ABOVE HUMAN FACTORS ADD FEAR. WITH LIGHTNING WHIRLING AROUND THE ACFT AND THUNDER SO LOUD IT COULD BLOCK OUT RADIO XMISSIONS, YES I WAS LITTLE SCARED. I WISH I WAS AS PERFECT AND AS FEARLESS AS THE ATC COMPUTER.

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.