Narrative:

The flight was a maintenance test flight with the aircraft owner flying as first officer and his employee and chief pilot flying as captain. The purpose of the flight was to test a new fuel computer controller which had been installed in an attempt to cure a throttle split. For this reason, the flight had to be conducted at high altitude, and therefore, on an IFR flight plan although the WX was visual with scattered clouds at 8000 ft and visibility of 20-30 mi. A new clearance and routing from ilg, returning to ilg, was received immediately prior to takeoff. The routing involved several fixes and radials. The clearance was read back and confirmed. On takeoff and climb out, although there did not seem to be much IFR traffic, there were frequent frequency changes and the flight was otherwise very busy because the captain, who was the PF, was controling the airplane and attempting to note the synchronization of engine instruments in order to check out the new fuel computer. An assigned altitude of 17000 ft on climb out was deviated to 17800 ft for approximately 10 seconds. Subsequent to this deviation, ATC clrncs to track radials of the ptw VOR were deviated twice to the extent of an estimated 4 or 5 mi. After passing ptw and proceeding to rav, things settled down and there were no further deviations. The altitude deviation was observed by the captain and first officer and the course deviations were observed by the center controller who pointed them out to the crew. The largest contributing factor to the deviations were the lengthy clearance received just prior to takeoff together with the distrs of the maintenance test flight activity. In retrospect, the crew should have taken the time before takeoff to enter the flight plan into the VLF system aboard the airplane rather than rely upon the primary navigation system. The nature of the VLF system discourages last min flight plan entry because latitudes and longitudes must be looked up and entered for each waypoint. This will be cured for this aircraft, and many similar aircraft with the replacement of the VLF system with GNS system with databases this summer. Nonetheless, the crew should have taken the time to enter the flight plan and should have been more situationally aware and avoided the deviations.

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Original NASA ASRS Text

Title: FLC OF A LEAR JET LR35, OVERSHOT CLB ALT AND FAILED TO FOLLOW THEIR ASSIGNED TRACK DURING AN ENG CTLR EQUIP TEST FLT.

Narrative: THE FLT WAS A MAINT TEST FLT WITH THE ACFT OWNER FLYING AS FO AND HIS EMPLOYEE AND CHIEF PLT FLYING AS CAPT. THE PURPOSE OF THE FLT WAS TO TEST A NEW FUEL COMPUTER CTLR WHICH HAD BEEN INSTALLED IN AN ATTEMPT TO CURE A THROTTLE SPLIT. FOR THIS REASON, THE FLT HAD TO BE CONDUCTED AT HIGH ALT, AND THEREFORE, ON AN IFR FLT PLAN ALTHOUGH THE WX WAS VISUAL WITH SCATTERED CLOUDS AT 8000 FT AND VISIBILITY OF 20-30 MI. A NEW CLRNC AND ROUTING FROM ILG, RETURNING TO ILG, WAS RECEIVED IMMEDIATELY PRIOR TO TKOF. THE ROUTING INVOLVED SEVERAL FIXES AND RADIALS. THE CLRNC WAS READ BACK AND CONFIRMED. ON TKOF AND CLBOUT, ALTHOUGH THERE DID NOT SEEM TO BE MUCH IFR TFC, THERE WERE FREQUENT FREQ CHANGES AND THE FLT WAS OTHERWISE VERY BUSY BECAUSE THE CAPT, WHO WAS THE PF, WAS CTLING THE AIRPLANE AND ATTEMPTING TO NOTE THE SYNCHRONIZATION OF ENG INSTS IN ORDER TO CHK OUT THE NEW FUEL COMPUTER. AN ASSIGNED ALT OF 17000 FT ON CLBOUT WAS DEVIATED TO 17800 FT FOR APPROX 10 SECONDS. SUBSEQUENT TO THIS DEV, ATC CLRNCS TO TRACK RADIALS OF THE PTW VOR WERE DEVIATED TWICE TO THE EXTENT OF AN ESTIMATED 4 OR 5 MI. AFTER PASSING PTW AND PROCEEDING TO RAV, THINGS SETTLED DOWN AND THERE WERE NO FURTHER DEVS. THE ALTDEV WAS OBSERVED BY THE CAPT AND FO AND THE COURSE DEVS WERE OBSERVED BY THE CTR CTLR WHO POINTED THEM OUT TO THE CREW. THE LARGEST CONTRIBUTING FACTOR TO THE DEVS WERE THE LENGTHY CLRNC RECEIVED JUST PRIOR TO TKOF TOGETHER WITH THE DISTRS OF THE MAINT TEST FLT ACTIVITY. IN RETROSPECT, THE CREW SHOULD HAVE TAKEN THE TIME BEFORE TKOF TO ENTER THE FLT PLAN INTO THE VLF SYS ABOARD THE AIRPLANE RATHER THAN RELY UPON THE PRIMARY NAV SYS. THE NATURE OF THE VLF SYS DISCOURAGES LAST MIN FLT PLAN ENTRY BECAUSE LATITUDES AND LONGITUDES MUST BE LOOKED UP AND ENTERED FOR EACH WAYPOINT. THIS WILL BE CURED FOR THIS ACFT, AND MANY SIMILAR ACFT WITH THE REPLACEMENT OF THE VLF SYS WITH GNS SYS WITH DATABASES THIS SUMMER. NONETHELESS, THE CREW SHOULD HAVE TAKEN THE TIME TO ENTER THE FLT PLAN AND SHOULD HAVE BEEN MORE SITUATIONALLY AWARE AND AVOIDED THE DEVS.

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.