B747-400
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Communication Breakdown; Confusion; Distraction; Workload
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification
Procedure; Human Factors; Aircraft; ATC Equipment / Nav Facility / Buildings
We left CVG on an unfamiliar departure and a very southern route that none of us had seen before. We were lighter than planned and climbed up to FL370 right away. After getting into New York airspace; they asked us what we wanted for a crossing altitude and Mach #. We replied FL370 and Mach .83.They asked if we could climb to FL 380; we hemmed and hawed; and said we could do it; but preferred to stay at FL370. They then asked us if we could do it by JOBOC. We said yes at M.840. We then amended the speed request to M.85; said we would do it at M.85 by JOBOC. A deal was done. The previous was on VHF voice. We passed JOBOC AND 4160N. We got a Control-Pilot Data Link Communications (CPDLC) request to climb to FL 390. We rejected that request due to aircraft performance' We then got another request to descend to FL370 by 1258Z. There was a second page to the request that said we had a route change. There was a 'LOAD' prompt. We thought we accepted only the altitude change; and activated the 'report level' function. Be aware that we had been negotiating on altitudes only up until this point. They snuck this route change in with no prior notification or warning or an 'advisory' message stating that our original clearance had changed. The 'LOAD' prompt was selected; and the new route populated the CDU. Right away we got an 'insufficient fuel' message. We looked at the new route; and it had us starting two (2) way points BEHIND our current position. We looked at the new route (the first page) and thought it was the same route so we erased the 'new route before we activated it thinking that was an erroneous fluke. As best we can guess; on page 2 of the new route; they had changed the coast in point from LIMRI to ADARA. At 1435Z; somewhere between 5130N and 5220N we received a CPDLC request to contact Shanwick on HF. They asked us our route after 5220N and we replied 'LIMRI' They said that was wrong; we were supposed to be going to ADARA. Then they called back and said we could continue to LIMRI but they would be filing a report. The 'system' caught the error before any deviations were committed.I suggest that ATC not give a route change without an advisory warning. And to not give a route change when the previous request was an altitude change only. All via CPDLC. When getting a voice oceanic clearance; we are required to acknowledge explicitly that we have a different route than our original clearance. This is not so with CPDLC. As a side note; we were requested by the company to accomplish some manual revisions prior to departure which we were NOT able to complete; so; we were trying to finish the revisions in cruise. We received two ACARS queries from the company wanting to know if we had completed the revisions. We were a bit distracted trying to accomplish the company requested non-operational duties; and that may have distracted us to a point where a mistake was made.
Even though no deviation from a clearance actually occurred; if this is how it all happened; which seems to be the most logical; then it appears to me that New York's practice of issuing multiple changes (i.e temporary FL change and a route change more than one thousand miles distant) in one Controller Pilot Data Link Communication (CPDLC) communication is an unsafe practice that lends itself to many misinterpretations and errors.When sending amended or revised CPDLC clearances; send only one (1 item) per message to acknowledge. I.e. altitude; speed; or route/fixes; only one per message; not multiple as this form of communication is very simplistic and doesn't lend well to complex clearances.
Following extensive pre-departure negotiation with ATC; re-flight levels and Mach numbers for an Atlantic crossing the flight crew of a B747-400; was chagrinned and confused when; while enroute and after coasting out; they received a Controller Pilot Data Link Communications(CPDLC) message from ATC reclearing them by a different route which when 'loaded' per the CPDLC prompt started at a waypoint several waypoints behind them. Believing the route change actually continued to reflect their current route they failed to activate the new route which; subsequent to the fixes behind them upon receipt was; in fact; different.