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20210504005239I

Incident · Minor damage
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FAA incident report · Aerovodochody L-29 DELFIN · Hollister, CA · May 4, 2021

FAA Aviation Safety Information Portal

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Date
May 4, 2021 · 16:23 local
Place
Hollister, CA
Airport
Hollister Municipal
Phase of flight
Landing: Approach
Operating rules
General operating rules (Part 91)
Damage
Minor damage
Aircraft
N129MR
Reported as
Aerovodochody L-29 Delfin
Reported engine
Motorlet M-701C
People aboard
1
Fatal injuries
0
Other injuries
0
Pilot’s certificates
Airline transport, commercial pilot, flight instructor
Pilot’s flight hours
22,000 total120 in this make and model210 in the last 90 days
N129MRRegistered now · Aerovodochody L-29 DELFINS/N 1234Airframe modelAerovodochody L-29 DELFINEngine modelMotorlet M-701CTurbo-jet

From the FAA’s Accident/Incident Data System (AIDS), through its Aviation Safety Information Portal, as reported. The NTSB investigates accidents separately, and its record of an accident is the fuller one. The aircraft is matched to the registry 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.

What happened

The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.

The landing gear did not come down. The main hydraulic pressure hose of the L-29 failed when the hose broke off in the hose fitting. The result was the normal hydraulic system depressurized. The emergency extension of the landing gear requires to tie into the normal hydraulic system by way of a manual valve. Because the two systems are interconnected, and the normal side was open to the atmosphere, the emergency hydraulic system accumulator pushed any available fluid out the compromised opening. The result of the broken pressure hose was the failure of the landing gear to go down and locked.

As the FAA filed it

THE LANDING GEAR DID NOT COME DOWN. THE MAIN HYDRAULIC PRESSURE HOSE OF THE L-29 FAILED WHEN THE HOSE BROKE OFF IN THE HOSE FITTING. THE RESULT WAS THE NORMAL HYDRAULIC SYSTEM DEPRESSURIZED. THE EMERGENCY EXTENSION OF THE LANDING GEAR REQUIRES TO TIE INTO THE NORMAL HYDRAULIC SYSTEM BY WAY OF A MANUAL VALVE. BECAUSE THE TWO SYSTEMS ARE INTERCONNECTED, AND THE NORMAL SIDE WAS OPEN TO THE ATMOSPHERE, THE EMERGENCY HYDRAULIC SYSTEM ACCUMULATOR PUSHED ANY AVAILABLE FLUID OUT THE COMPROMISED OPENING. THE RESULT OF THE BROKEN PRESSURE HOSE WAS THE FAILURE OF THE LANDING GEAR TO GO DOWN AND LOCKED.