Narrative:

We were deviating south of course around thunderstorm activity. This caused center to say ' I'll be losing you on radar; fly present heading and intercept [airway] to [fix] direct [fix] maintain FL320'. The PF (captain) put the radial from [fix] into the FMS and we began to intercept it. At this point center said that he still showed us east of the [airway]; but we lost communication with ATC at that moment before we could verify what radial ATC wanted us to intercept. We were trying to verify what course ATC wanted; and also were working our way around the thunderstorms. For several minutes; we were unable to contact ATC for clarification. At this time; the captain said on center frequency and on guard frequency that he would be 'exercising emergency authority' to deviate around the weather.we were then able to regain radio contact with center; and center expressed concern that we were not on [airway]; and then issued us a clearance to climb to 33;000 feet as a precaution to be sure that we didn't get within 20 miles of separation of another aircraft. We reported level at 33;000 feet; and center was satisfied that no loss of separation had occurred. Minutes later; he regained radar coverage; and we completed the rest of the flight uneventfully.the difficulty in complying with the clearance to intercept [airway] from two factors: the wording of ATC's clearance led us to believe that we were south of [fix] when in fact we were a little bit south of [fix]. There is a bend in the airway at [fix]; so intercepting the 142 radial; was not accomplishing what ATC wanted. We could not get [airway] to show in the FMS; because we didn't have the anchor point south of [fix]. Our jeppesen chart cuts off at the border; and does not show the bend in the airway; or anything south of [fix].this would have been rectified easily with a radial from ATC; but we lost radio contact before we could get one.

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Original NASA ASRS Text

Title: A B737-800 aircraft deviating for weather was issued a reroute. The crew did not have the charts depicting the route issued to them. The flight did not comply with their assigned route and flew out of radio and radar coverage for a period of time deviating on their own navigation for weather.

Narrative: We were deviating south of course around Thunderstorm activity. This caused Center to say ' I'll be losing you on Radar; fly present heading and intercept [airway] to [fix] direct [fix] Maintain FL320'. The PF (Captain) put the radial from [fix] into the FMS and we began to intercept it. At this point Center said that he still showed us East of the [airway]; but we lost communication with ATC at that moment before we could verify what radial ATC wanted us to intercept. We were trying to verify what course ATC wanted; and also were working our way around the thunderstorms. For several minutes; we were unable to contact ATC for clarification. At this time; the Captain said on Center Frequency and on Guard Frequency that he would be 'Exercising Emergency Authority' to deviate around the weather.We were then able to regain radio contact with Center; and Center expressed concern that we were not on [airway]; and then issued us a clearance to climb to 33;000 feet as a precaution to be sure that we didn't get within 20 miles of separation of another aircraft. We reported level at 33;000 feet; and Center was satisfied that no loss of separation had occurred. Minutes later; he regained radar coverage; and we completed the rest of the flight uneventfully.The difficulty in complying with the clearance to intercept [airway] from two factors: The wording of ATC's clearance led us to believe that we were south of [fix] when in fact we were a little bit south of [fix]. There is a bend in the airway at [fix]; so intercepting the 142 radial; was not accomplishing what ATC wanted. We could not get [airway] to show in the FMS; because we didn't have the anchor point South of [fix]. Our Jeppesen Chart cuts off at the border; and does not show the bend in the airway; or anything South of [fix].This would have been rectified easily with a radial from ATC; but we lost radio contact before we could get one.

Data retrieved from NASA's ASRS site 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.