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An LR25 flight crew experiences main gear doors opening near maximum cruise speed at FL250. Aircraft pitches up as a result of partial opening of doors.
| Attributes | |
| ACN | 430834 |
| Time | |
| Date | 199903 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : pxt.vortac |
| State Reference | MD |
| Altitude | msl bound lower : 25000 msl bound upper : 25300 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc.artcc |
| Operator | common carrier : charter |
| Make Model Name | Learjet 25 |
| Operating Under FAR Part | Part 135 |
| Navigation In Use | other vortac |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : charter |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : commercial pilot : cfi pilot : atp pilot : multi engine |
| Experience | flight time last 90 days : 75 flight time total : 8000 flight time type : 5200 |
| ASRS Report | 430834 |
| Person 2 | |
| Affiliation | company : charter |
| Function | flight crew : first officer |
| Qualification | pilot : multi engine pilot : instrument pilot : commercial |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance non adherence other other anomaly |
| Independent Detector | atc equipment other atc equipment : radar aircraft equipment other aircraft equipment : door wind lites other controllera other flight crewa other flight crewb |
| Resolutory Action | aircraft : equipment problem dissipated controller : issued new clearance flight crew : regained aircraft control other |
| Consequence | other other |
| Factors | |
| Maintenance | performance deficiency : inspection |
| Supplementary | |
| Problem Areas | Environmental Factor Aircraft |
| Primary Problem | Aircraft |
Narrative:
Level at FL250. Center asked for best forward speed (350 KIAS). Accelerating through +/-330 KTS, aircraft shook, pitched up, and main gear doors unlocked lights came on. Power reduced to reduce airspeed, but pitch up caused us to +/-200 ft high. Center questioned our altitude. Do not think we got more than 200 ft high, but we may have. As aircraft slowed, we informed center of our problem. They broke out all traffic that was following us on the STAR, we continued to slow to approximately 200 KIAS (gear extended/retract speed -- vle). Cycled gear down -- 3 greens. With main gear door unlocked, lights still on, elected to retract gear. Still had 2 red gear door lights. Continued to destination at reduced speed (had to burn fuel to make landing weight. Otherwise, we would have gone to closest airport). In descent, red lights went out without crew intervention. At destination, selected gear down, all system normal. Had maintenance inspect gear system. Found gear door hinges bent (from airloads?) but could not find any other problems. Plan to replace gear door selector valve to preclude recurrence even though we could not duplicate the problem.
Original NASA ASRS Text
Title: AN LR25 FLC EXPERIENCES MAIN GEAR DOORS OPENING NEAR MAX CRUISE SPD AT FL250. ACFT PITCHES UP AS A RESULT OF PARTIAL OPENING OF DOORS.
Narrative: LEVEL AT FL250. CTR ASKED FOR BEST FORWARD SPD (350 KIAS). ACCELERATING THROUGH +/-330 KTS, ACFT SHOOK, PITCHED UP, AND MAIN GEAR DOORS UNLOCKED LIGHTS CAME ON. PWR REDUCED TO REDUCE AIRSPD, BUT PITCH UP CAUSED US TO +/-200 FT HIGH. CTR QUESTIONED OUR ALT. DO NOT THINK WE GOT MORE THAN 200 FT HIGH, BUT WE MAY HAVE. AS ACFT SLOWED, WE INFORMED CTR OF OUR PROB. THEY BROKE OUT ALL TFC THAT WAS FOLLOWING US ON THE STAR, WE CONTINUED TO SLOW TO APPROX 200 KIAS (GEAR EXTENDED/RETRACT SPD -- VLE). CYCLED GEAR DOWN -- 3 GREENS. WITH MAIN GEAR DOOR UNLOCKED, LIGHTS STILL ON, ELECTED TO RETRACT GEAR. STILL HAD 2 RED GEAR DOOR LIGHTS. CONTINUED TO DEST AT REDUCED SPD (HAD TO BURN FUEL TO MAKE LNDG WT. OTHERWISE, WE WOULD HAVE GONE TO CLOSEST ARPT). IN DSCNT, RED LIGHTS WENT OUT WITHOUT CREW INTERVENTION. AT DEST, SELECTED GEAR DOWN, ALL SYS NORMAL. HAD MAINT INSPECT GEAR SYS. FOUND GEAR DOOR HINGES BENT (FROM AIRLOADS?) BUT COULD NOT FIND ANY OTHER PROBS. PLAN TO REPLACE GEAR DOOR SELECTOR VALVE TO PRECLUDE RECURRENCE EVEN THOUGH WE COULD NOT DUPLICATE THE PROB.
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.