Narrative:

While cruising at FL330 on J-5 at ehf, a clearance was received to cross 25 mi northwest of pmd at FL240 from ZLA. The route of flight from this point was J-65 to lando intersection on the ehf 126 degree radial and then J-65 to pmd on the 295 degree radial (bearing 115 degrees). The aircraft's navigation computer had been programmed incorrectly with lando intersection aft er palmdale instead of prior to palmdale as the route required. To compensate for this, lando intersection was selected for direct routing. On arrival at lando, the computer bypassed pmd and went to the next waypoint. At this time, the PF who was also descending the aircraft to meet the crossing altitude restr asked for the inbound bearing to pmd on the jet route. He was given 104 degrees in error by the other pilot instead of the correct bearing of 114 degrees. Some confusion was experienced while this error was resolved. While descending at in excess of 5000 FPM, ZLA called and said the crossing restr would not be made. This transmission was acknowledged. Next, at FL265, ZLA said to level at FL260. A leveloff was immediately initiated and ZLA was advised that this maneuver could not be accomplished by FL260. ZLA replied 'maintain FL260.' the aircraft leveled at FL257 and was returned to FL260. The problem was started by a series of distrs for the PF caused by navigation errors. The PNF had failed to check the order of the computer waypoints and had made a subtraction error converting a radial to an inbound bearing. He was also attempting to get ATIS information and inform the FBO of the aircraft's arrival time. The confusion in navigation distracted the PF from a more aggressive descent schedule. ZLA's request for a leveloff from a high rate of descent without more warning placed the PF in a situation where he could not respond faster than he did.

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Original NASA ASRS Text

Title: ALTDEV ALT OVERSHOT NAV ERROR.

Narrative: WHILE CRUISING AT FL330 ON J-5 AT EHF, A CLRNC WAS RECEIVED TO CROSS 25 MI NW OF PMD AT FL240 FROM ZLA. THE RTE OF FLT FROM THIS POINT WAS J-65 TO LANDO INTXN ON THE EHF 126 DEG RADIAL AND THEN J-65 TO PMD ON THE 295 DEG RADIAL (BEARING 115 DEGS). THE ACFT'S NAV COMPUTER HAD BEEN PROGRAMMED INCORRECTLY WITH LANDO INTXN AFT ER PALMDALE INSTEAD OF PRIOR TO PALMDALE AS THE RTE REQUIRED. TO COMPENSATE FOR THIS, LANDO INTXN WAS SELECTED FOR DIRECT ROUTING. ON ARR AT LANDO, THE COMPUTER BYPASSED PMD AND WENT TO THE NEXT WAYPOINT. AT THIS TIME, THE PF WHO WAS ALSO DSNDING THE ACFT TO MEET THE XING ALT RESTR ASKED FOR THE INBOUND BEARING TO PMD ON THE JET RTE. HE WAS GIVEN 104 DEGS IN ERROR BY THE OTHER PLT INSTEAD OF THE CORRECT BEARING OF 114 DEGS. SOME CONFUSION WAS EXPERIENCED WHILE THIS ERROR WAS RESOLVED. WHILE DSNDING AT IN EXCESS OF 5000 FPM, ZLA CALLED AND SAID THE XING RESTR WOULD NOT BE MADE. THIS XMISSION WAS ACKNOWLEDGED. NEXT, AT FL265, ZLA SAID TO LEVEL AT FL260. A LEVELOFF WAS IMMEDIATELY INITIATED AND ZLA WAS ADVISED THAT THIS MANEUVER COULD NOT BE ACCOMPLISHED BY FL260. ZLA REPLIED 'MAINTAIN FL260.' THE ACFT LEVELED AT FL257 AND WAS RETURNED TO FL260. THE PROB WAS STARTED BY A SERIES OF DISTRS FOR THE PF CAUSED BY NAV ERRORS. THE PNF HAD FAILED TO CHK THE ORDER OF THE COMPUTER WAYPOINTS AND HAD MADE A SUBTRACTION ERROR CONVERTING A RADIAL TO AN INBOUND BEARING. HE WAS ALSO ATTEMPTING TO GET ATIS INFO AND INFORM THE FBO OF THE ACFT'S ARR TIME. THE CONFUSION IN NAV DISTRACTED THE PF FROM A MORE AGGRESSIVE DSCNT SCHEDULE. ZLA'S REQUEST FOR A LEVELOFF FROM A HIGH RATE OF DSCNT WITHOUT MORE WARNING PLACED THE PF IN A SIT WHERE HE COULD NOT RESPOND FASTER THAN HE DID.

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.