Narrative:

The flight was a once-a-week honolulu (hnl) - christmas island (cxi) turnaround trip, leaving hnl at XB00 local time, arriving cxi XE00, departing cxi at approximately XF00 for an arrival at hnl at XI00. En route communications are with ZOA via honolulu commercial on HF radio. On this flight, a clearance was requested for the cxi-hnl return flight while still airborne en route to cxi. The clearance was from cxi to hnl 'as filed' except to climb and maintain FL280, report reaching the altitude. Filed altitude was FL330. Departure from cxi was approximately 10 mins before clearance void time, and an off-report was made with hnl comm radio erroneously indicating an intended climb to FL330. The report was acknowledged. After reaching FL330, we acknowledged a call from hnl relaying from ZOA that we had only been cleared to FL280, but 'for clarification', were now cleared to FL330. We had deviated from assigned altitude by 5000'. The obvious cause of the error was a failure on our part to adhere to the copied clearance. Being a 'backside of the clock' flight (crew check-in was at XA00), it is rare for both crew members to feel well rested and at peak alertness for the duration of duty. The flight was the captain's second extended-range trip during his employment with the company, the only prior one being a month previous with a company check airman in the observer's seat. It was my 8TH trip to this destination, the second in a 6-MONTH period. Crew attention, therefore, was somewhat diverted to matters unique to the type of flight being conducted, allowing oversight of a very basic course of action.

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Original NASA ASRS Text

Title: ACR MLG ALT DEVIATION OVERSHOT DURING CLIMB BY 5000'. ACFT WAS EXTENDED OVER WATER OPERATION SOUTH OF HNL.

Narrative: THE FLT WAS A ONCE-A-WEEK HONOLULU (HNL) - CHRISTMAS ISLAND (CXI) TURNAROUND TRIP, LEAVING HNL AT XB00 LOCAL TIME, ARRIVING CXI XE00, DEPARTING CXI AT APPROX XF00 FOR AN ARR AT HNL AT XI00. ENRTE COMS ARE WITH ZOA VIA HONOLULU COMMERCIAL ON HF RADIO. ON THIS FLT, A CLRNC WAS REQUESTED FOR THE CXI-HNL RETURN FLT WHILE STILL AIRBORNE ENRTE TO CXI. THE CLRNC WAS FROM CXI TO HNL 'AS FILED' EXCEPT TO CLIMB AND MAINTAIN FL280, REPORT REACHING THE ALT. FILED ALT WAS FL330. DEP FROM CXI WAS APPROX 10 MINS BEFORE CLRNC VOID TIME, AND AN OFF-REPORT WAS MADE WITH HNL COMM RADIO ERRONEOUSLY INDICATING AN INTENDED CLIMB TO FL330. THE REPORT WAS ACKNOWLEDGED. AFTER REACHING FL330, WE ACKNOWLEDGED A CALL FROM HNL RELAYING FROM ZOA THAT WE HAD ONLY BEEN CLRED TO FL280, BUT 'FOR CLARIFICATION', WERE NOW CLRED TO FL330. WE HAD DEVIATED FROM ASSIGNED ALT BY 5000'. THE OBVIOUS CAUSE OF THE ERROR WAS A FAILURE ON OUR PART TO ADHERE TO THE COPIED CLRNC. BEING A 'BACKSIDE OF THE CLOCK' FLT (CREW CHECK-IN WAS AT XA00), IT IS RARE FOR BOTH CREW MEMBERS TO FEEL WELL RESTED AND AT PEAK ALERTNESS FOR THE DURATION OF DUTY. THE FLT WAS THE CAPT'S SECOND EXTENDED-RANGE TRIP DURING HIS EMPLOYMENT WITH THE COMPANY, THE ONLY PRIOR ONE BEING A MONTH PREVIOUS WITH A COMPANY CHECK AIRMAN IN THE OBSERVER'S SEAT. IT WAS MY 8TH TRIP TO THIS DEST, THE SECOND IN A 6-MONTH PERIOD. CREW ATTN, THEREFORE, WAS SOMEWHAT DIVERTED TO MATTERS UNIQUE TO THE TYPE OF FLT BEING CONDUCTED, ALLOWING OVERSIGHT OF A VERY BASIC COURSE OF ACTION.

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.