# Incident 20250421004299I: Aerovodochody L-29 DELFIN, Tehachapi, CA, April 21, 2025 - Type: FAA incident report (Accident/Incident Data System), as reported - Date: April 21, 2025, 18:50 local time - Place: Tehachapi, CA - Airport: Tehachapi - Damage: Minor damage - Phase of flight: Landing: Touchdown - Operating rules: General operating rules (Part 91) - Location: 35.1350° N, 118.4393° W: Placed by OpenAirDocs at TEHACHAPI MUNI (TSP), within about a mile (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=35.1350&lon=-118.4393&mi=10 - Aircraft: N154MM, registered now (https://openairdocs.org/aircraft/N154MM) (OpenAirDocs) - Registry model: Aerovodochody L-29 DELFIN (registry code 0564310, https://openairdocs.org/model/aerovodochody-l-29-delfin) (OpenAirDocs) - Registry engine: Pratt & Whitney J60P-5A (registry code 51760, https://openairdocs.org/engine/pratt-whitney-j60p-5a) (OpenAirDocs) - Reported make and model: AEROVODOCHODY L-29 DELFIN - Reported engine: P & W J60P-5A - People aboard: 2 - Fatal injuries: 0 - Other injuries: 0 - Pilot certificates: Airline transport - Pilot flight hours: 6,905 total - FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/) - Page: https://openairdocs.org/incident/20250421004299I ## Narrative As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^. AT APPROXIMATELY 17:30 LOCAL TIME ON 21 APRIL 2025, THE AIRMAN DEPARTED KTSP IN N154MM ON A LOCAL FLIGHT. THE AIRCRAFT WAS TOPPED OFF WITH 264 GALLONS OF JET-A FUEL, SUFFICIENT FOR APPROXIMATELY 1H45M FLIGHT TIME. PRIOR TO ENGINE START, THE HYDRAULIC TANK WAS CHECKED AND FOUND TO BE JUST BELOW THE “HIGH” MARK ON THE DIPSTICK, INDICATING A PROPERLY SERVICED HYDRAULIC SYSTEM. DEPARTURE WAS OFF OF RUNWAY 29. THE CLIMB AND CRUISE WERE UNEVENTFUL UNTIL APPROXIMATELY 45 MINUTES INTO THE FLIGHT, WHEN THE AIRMAN NOTICED A SLIGHT BUFFET IN THE RUDDER PEDALS. THIS VIBRATION IS INDICATIVE OF THE SPEED BRAKES BEING OPEN. THE SPEED BRAKES HAD BEEN EXTENDED BUT HAD JUST BEEN COMMANDED CLOSED, SO THIS DISAGREEMENT IN POSITION WAS UNUSUAL. THE AIRMAN CONFIRMED THE STATUS OF THE SPEED BRAKES, WHICH ARE HYDRAULICALLY POWERED OFF OF A SINGLE OPEN-CENTER HYDRAULIC SYSTEM, ALONG WITH THE GEAR AND THE FLAPS. THIS FAILURE DROVE THE AIRMAN TO LOOK AT HYDRAULIC PRESSURE, WHICH READ 0 PSI. THE AIRMAN CLIMBED TO A SAFE ALTITUDE TO INVESTIGATE AND PROCEEDED TO AN UNPOPULATED AREA JUST NORTH OF THE RUNWAY IN TEHACHAPI. PER THE EMERGENCY PROCEDURES ON THIS AIRCRAFT, THE AIRMAN SLOWED TO GEAR EXTENSION SPEED AND THEN 1) COMMANDED A NORMAL GEAR EXTENSION, WHICH RESULTED IN NO CHANGE. 2) USED THE BACKUP HYDRAULIC SWITCH TO COMMAND AN EXTENSION; AGAIN, NO STATE CHANGE. 3) VERIFIED SUFFICIENT ACCUMULATOR PRESSURE AND USED THE “EMERGENCY GEAR EXTENSION” VALVE TO EXTEND THE GEAR USING THE EMERGENCY HYDRAULIC ACCUMULATORS. THIS RESULTED IN AN ALMOST IMMEDIATE DROP OF THE ACCUMULATOR PRESSURE TO 0, AND THE LEFT MAIN GEAR “UP-LOCK” LIGHT EXTINGUISHING. THE AIRMAN COULD NOT SEE THE LEFT GEAR DOWN, AND THE MECHANICAL INDICATOR SHOWED IT STILL UP. THERE WAS ANOTHER AIRCRAFT AIRBORNE THAT WAS ABLE TO CONDUCT A “CLEAN AND DRY” CHECK, AND THEY REPORTED THE LEFT GEAR DOOR OPEN, BUT THE LEFT GEAR STILL RETRACTED. DUE TO THE EXTREME DANGER OF LANDING WITH ASYMMETRIC GEAR, THIS RESULTED IN NO FURTHER TROUBLESHOOTING OR ATTEMPTS TO EXTEND THE GEAR. LANDING GEAR UP IS NOT IDEAL, BUT DOING SO WITH ASYMMETRIC GEAR IS EXTREMELY RISKY. THE AIRMAN LIMITED THE REST OF THE FLIGHT TO MINIMAL BANK ANGLE TURNS, MINIMAL G-LOADING, AND A SERIES OF PRACTICE APPROACHES TO RUNWAY 29 IN ORDER TO GET THE SIGHT PICTURE CORRECT FOR LANDING WITH NO FLAPS AND NO GEAR. THE AIRMAN WAS ABLE TO CONFER WITH THE GROUND CREW, WHO WERE EXTREMELY FAMILIAR WITH THE AIRCRAFT AND HOW TO OPEN THE CANOPIES IN THE EVENT THE AIRMAN AND THE PASSENGER NEEDED TO BE PULLED OUT. THE GROUND CREW STAGED IN SEVERAL TRUCKS WITH FIRE EXTINGUISHERS BY THE RUNWAY AND PLANNED TO FOLLOW N154MM ON THE ROLLOUT TO PROVIDE ESCAPE HELP AND FIRE SUPPRESSION WHEN NEEDED. THE GROUND CREW ALSO CONCURRED WITH OUR COURSE OF ACTION TO EXECUTE AN INTENTIONAL GEAR-UP LANDING ON THE PAVEMENT. THE AIRMAN CONTINUED TO LOITER, EXECUTING APPROXIMATELY 5 PRACTICE APPROACHES. ON DOWNWIND OF THE FIRST INTENDED LANDING ATTEMPT, THE AIRMAN MANUALLY COMMANDED THE OUTFLOW VALVE FULLY OPEN AND DEFLATED CANOPY SEALS TO ALLOW FOR QUICK EGRESS AFTER LANDING. THE AIRMAN ELECTED TO TURN OFF THE ELECTRIC BOOST PUMP TO MINIMIZE THE RISK OF FIRE AFTER LANDING. THE AIRMAN ALLOWED THE TOUCHDOWN TO BE AT A HIGHER SPEED THAN NORMAL TO AVOID HAVING TOO MUCH THETA ON THE AIRPLANE. JUST PRIOR TO TOUCHDOWN, THE AIRMAN COMMANDED A NORMAL ENGINE SHUTDOWN. TOUCHDOWN WAS APPROXIMATELY 91 KIAS, AND DECELERATION WAS AKIN TO MODERATE TO HEAVY BRAKING. THE AIRMAN HAD GOOD DIRECTION CONTROL DURING THE SLIDEOUT, AND TOWARDS THE END, THE AIRMAN WAS ABLE TO MOVE THE AIRCRAFT TO THE RIGHT SIDE OF THE RUNWAY BUT REMAIN ON THE PAVEMENT. UPON COMING TO A STOP, THE AIRMAN COMMANDED AN EVACUATION OF THE AIRCRAFT, SHUT DOWN ELECTRICAL POWER, AND THEN EGRESSED THE AIRCRAFT. THERE WERE NO INJURIES, AND THE CANOPIES PERFORMED NORMALLY AND OPENED EASILY, UNLOCKING CORRECTLY. From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.