Date: 201204
Local time of day: 1201-1800
Location: ZFW.ARTCC, TX
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZFW
ATC / advisory: Center ZFW
Aircraft component: ACARS
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown
Anomaly: ATC Issue All Types; Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented
Contributing factors: Procedure; Human Factors; Aircraft
Primary problem: Ambiguous

Narrative: This incident started while in cruise at FL360 southeast of DFW. We checked in to Fort Worth Center and were direct to LBL. We first noticed that the ACARS had stopped functioning. No ATSU menu information was available; printer function stopped etc. What little troubleshooting we could do didn't help. We waited a little while to see if it would begin working again and after about ten minutes selected the appropriate Commercial Radio frequency on the number 2 radio to monitor (131.65). Another carrier was using the frequency to deal with a lengthy medical emergency. Unknown to us at this time ATC had failed to pass us off to the next sector frequency. Several distractions from the cabin occurred; a bathroom break; etc. We passed into the next Commercial Radio sector and switched to 131.30 which was quiet. Up to this point radio chatter on ATC was always present; and we had no real reason to suspect we had missed any radio calls. Approaching LBL it was apparent something was amiss and several calls to Fort Worth by us weren't answered. Another aircraft relayed a frequency to us and we contacted Kansas City on the correct frequency over LBL. Within a minute Dispatch was heard on Commercial Radio calling us. They requested we Confirm OPS Normal gave us the appropriate sector frequency and asked about ACARS messages that weren't answered. We told them the ACARS was inoperative and that we had reestablished ATC communications. The ACARS was reported inoperative to Maintenance upon landing. I called Dispatch and Fort Worth ATC after landing. They informed me we had flown through multiple sectors 'NORDO' over a period of about 25-28 minutes. Fort Worth said they had failed to properly hand us off but wanted to know why we couldn't be reached by company; etc. Other than listening better to subtle indications on the radio that we had flown past the hand off; the time elapsed and realizing over DFW sectors would be changing quickly I don't see much else we could have done differently. Dispatch tried to send us ACARS messages; but none got through. I didn't see an immediate need to call Dispatch via Commercial Radio to tell them our ACARS was inoperative; especially when the frequency was being used for an emergency. Sector frequency changes can occur in a little as a minute or more than 20 minutes. Sector lines and frequencies are not indicated on HI Charts as is the case on Latin American charts. Perhaps a sector change indicator could be incorporated into the NAV data base somehow. We have become very reliant on ACARS; yet will quickly try to dispatch aircraft with it inoperative. The requirement to monitor Commercial Radio with an inoperative ACARS is unknown to some and I could only find one small reference to it in the FOM. Monitoring guard is recommended; not required by the FOM.




Synopsis: A320 Captain reports an ACARS failure en route at FL360. At about the same time the aircraft flies out of the current ZFW sector without a frequency change. Over twenty minutes pass before the crew detects the lost comm situation and contacts Center.