Narrative:

During the return from an engineering certification flight test with a test pilot on board; the chase aircraft experienced a red pressure warning. The warning was reported to the lead aircraft but not as an emergency and to continue a normal descent to the runway. TRACON cleared the flight to 11000 ft on heading 045 degrees. The chase pilot did not inform the lead pilot that he had separated and remained at 15000 ft MSL. The chase pilot was sufficiently distraction during the heads-down troubleshooting to lose situational awareness and lose sight of the lead aircraft. The chase pilot determined that remaining at 15000 ft MSL was prudent until condition of aircraft was determined and re-acquired visual of the lead aircraft before descending. The flight was cleared to 10000 ft. After the flight was level at 10000 ft; the chase pilot reported that he lost sight of the lead aircraft and reported that he was above the lead aircraft. When asked what altitude; the chase pilot reported that he was still at 15000 ft MSL. The flight crew of the lead aircraft searched and acquired the chase airplane at 12 O'clock position and high. The chase aircraft was instructed to descend to 10000 ft for the rejoin. The chase pilot refused and stayed at 15000 ft MSL but followed the vectors provided by TRACON. The flight was cleared for a visual to the runway and both aircraft started to descend. The chase aircraft accelerated away from the lead aircraft and was ahead of the lead aircraft by 3-5 NM as reported by TRACON and eventually beyond visual range of the lead aircraft's flight crew. The chase aircraft contacted TRACON as -2 and landed separately ahead of the lead aircraft. At the debrief; the profile and recovery were discussed and the chase pilot was informed of his errors. Corrective actions: 1) revise checklists to reflect specific chase aircraft to reduce time to determine corrective action in-flight. 2) more formation and emergency training for the chase pilot. 3) improve company requirements. Supplemental information from acn 748482: to help avoid these sorts of distrs; the L39 operators will hold periodic reviews and training sessions as a group for lessons learned and to communicate unique characteristics of the company L39 aircraft. I am personally going to create an aircraft specific (with differences) checklist that is correlated to annunciator lights for better ease of use in the event of an airborne emergency. We will also include a copy of the L39 afm in the telemetry room during flight test chase sorties as an additional support means in the event of L39 emergency resolution.

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Original NASA ASRS Text

Title: L39 PLT WAS OPERATING AS CHASE PLANE FOR A CERTIFICATION TEST FLT. WHEN A MAINT PROBLEM DEVELOPED; FORMATION INTEGRITY WAS LOST WHEN THE CHASE PLANE DID NOT DESCEND AS THE LEAD ACFT DESCENDED.

Narrative: DURING THE RETURN FROM AN ENGINEERING CERTIFICATION FLT TEST WITH A TEST PLT ON BOARD; THE CHASE ACFT EXPERIENCED A RED PRESSURE WARNING. THE WARNING WAS RPTED TO THE LEAD ACFT BUT NOT AS AN EMER AND TO CONTINUE A NORMAL DSCNT TO THE RWY. TRACON CLRED THE FLT TO 11000 FT ON HDG 045 DEGS. THE CHASE PLT DID NOT INFORM THE LEAD PLT THAT HE HAD SEPARATED AND REMAINED AT 15000 FT MSL. THE CHASE PLT WAS SUFFICIENTLY DISTR DURING THE HEADS-DOWN TROUBLESHOOTING TO LOSE SITUATIONAL AWARENESS AND LOSE SIGHT OF THE LEAD ACFT. THE CHASE PLT DETERMINED THAT REMAINING AT 15000 FT MSL WAS PRUDENT UNTIL CONDITION OF ACFT WAS DETERMINED AND RE-ACQUIRED VISUAL OF THE LEAD ACFT BEFORE DSNDING. THE FLT WAS CLRED TO 10000 FT. AFTER THE FLT WAS LEVEL AT 10000 FT; THE CHASE PLT RPTED THAT HE LOST SIGHT OF THE LEAD ACFT AND RPTED THAT HE WAS ABOVE THE LEAD ACFT. WHEN ASKED WHAT ALT; THE CHASE PLT RPTED THAT HE WAS STILL AT 15000 FT MSL. THE FLT CREW OF THE LEAD ACFT SEARCHED AND ACQUIRED THE CHASE AIRPLANE AT 12 O'CLOCK POS AND HIGH. THE CHASE ACFT WAS INSTRUCTED TO DSND TO 10000 FT FOR THE REJOIN. THE CHASE PLT REFUSED AND STAYED AT 15000 FT MSL BUT FOLLOWED THE VECTORS PROVIDED BY TRACON. THE FLT WAS CLRED FOR A VISUAL TO THE RWY AND BOTH ACFT STARTED TO DSND. THE CHASE ACFT ACCELERATED AWAY FROM THE LEAD ACFT AND WAS AHEAD OF THE LEAD ACFT BY 3-5 NM AS RPTED BY TRACON AND EVENTUALLY BEYOND VISUAL RANGE OF THE LEAD ACFT'S FLT CREW. THE CHASE ACFT CONTACTED TRACON AS -2 AND LANDED SEPARATELY AHEAD OF THE LEAD ACFT. AT THE DEBRIEF; THE PROFILE AND RECOVERY WERE DISCUSSED AND THE CHASE PLT WAS INFORMED OF HIS ERRORS. CORRECTIVE ACTIONS: 1) REVISE CHKLISTS TO REFLECT SPECIFIC CHASE ACFT TO REDUCE TIME TO DETERMINE CORRECTIVE ACTION INFLT. 2) MORE FORMATION AND EMER TRAINING FOR THE CHASE PLT. 3) IMPROVE COMPANY REQUIREMENTS. SUPPLEMENTAL INFO FROM ACN 748482: TO HELP AVOID THESE SORTS OF DISTRS; THE L39 OPERATORS WILL HOLD PERIODIC REVIEWS AND TRAINING SESSIONS AS A GROUP FOR LESSONS LEARNED AND TO COMMUNICATE UNIQUE CHARACTERISTICS OF THE COMPANY L39 ACFT. I AM PERSONALLY GOING TO CREATE AN ACFT SPECIFIC (WITH DIFFERENCES) CHKLIST THAT IS CORRELATED TO ANNUNCIATOR LIGHTS FOR BETTER EASE OF USE IN THE EVENT OF AN AIRBORNE EMER. WE WILL ALSO INCLUDE A COPY OF THE L39 AFM IN THE TELEMETRY ROOM DURING FLT TEST CHASE SORTIES AS AN ADDITIONAL SUPPORT MEANS IN THE EVENT OF L39 EMER RESOLUTION.

Data retrieved from NASA's ASRS site as of January 2009 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.