ASN Aircraft accident Lockheed SP-2H Neptune N4692A Fresno Yosemite International Airport, CA (FAT)
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Status:Accident investigation report completed and information captured
Date:Sunday 15 June 2014
Type:Silhouette image of generic P2 model; specific model in this crash may look slightly different
Lockheed SP-2H Neptune
Operator:Minden Air Corporation
On behalf of:U.S. Forest Service
Registration: N4692A
MSN: 726-7247
First flight: 1961
Total airframe hrs:10484
Engines: 2 Wright R-3350-32WA Cyclone
Crew:Fatalities: 0 / Occupants: 2
Passengers:Fatalities: 0 / Occupants: 0
Total:Fatalities: 0 / Occupants: 2
Aircraft damage: Substantial
Aircraft fate: Written off (damaged beyond repair)
Location:Fresno Yosemite International Airport, CA (FAT) (   United States of America)
Phase: Landing (LDG)
Nature:Fire fighting
Departure airport:Porterville Airport, CA (PTV/KPTV), United States of America
Destination airport:Porterville Airport, CA (PTV/KPTV), United States of America
A Lockheed SP-2H, N4692A, was substantially damaged when the nose wheel landing gear collapsed during landing roll at the
Fresno Yosemite International Airport (FAT), Fresno, California. The airplane was registered to Minden Air Corporation and operated as Tanker 48 by the United States Department of Agriculture (USDA), Forestry Service.
The captain reported that following an uneventful aerial drop, the flight was returning to Porterville. During the descent check, he noticed that the hydraulic pressure indicated 0 and that the first officer subsequently verified that the sight gauge for the main hydraulic fluid reservoir was empty. The first officer opened the jet engine doors successfully as the captain selected gear down with no response. The captain notified base personnel at Porterville of the situation, and informed them that they would be orbiting to the east of the airport to troubleshoot. The captain and first officer performed the emergency checklist, and verified that the nose wheel landing gear was extended. The captain stated that the first officer then installed the pin in the nose wheel landing gear as part of the emergency checklist.
The flight diverted to Fresno due to a longer runway and emergency resources as both pilots briefed the no-flap landing procedure, airspeeds, and approach profile. As the flight continued toward Fresno, the flight crew informed Fresno Approach Control of the hydraulic system failure, and continued to perform the emergency gear extension checklist. The first officer extended the main landing gear using the emergency gear release, which resulted in three down and locked landing gear indications in the cockpit. As the flight neared Fresno, the first officer added 2 gallons of hydraulic fluid to the main hydraulic reservoir while the captain attempted to extend the flaps unsuccessfully. Subsequently, the flight landed normally on runway 26R.
During the landing roll, the nose wheel landing gear collapsed, and the airplane came to rest nose low.
The first officer reported that following completion of the emergency nose gear extension checklist, he physically inserted the nose gear pin in place prior to the landing at Fresno.
Examination of the airplane by representatives from the Forest Service revealed that the forward portion of the fuselage was structurally damaged. The airplane was recovered to a secure location for further examination.

Probable Cause:

PROBABLE CAUSE: "The collapse of the nosewheel landing gear due to the disengagement of the nosewheel landing gear pin. Contributing to the accident was the failure of the main hydraulic system due to overpressurization for reasons that could not be determined during postaccident examination of the airplane. "

Accident investigation:
Investigating agency: NTSB
Status: Investigation completed
Duration: 1 year and 3 months
Accident number: WPR14TA248
Download report: Summary report

Landing gear collapse
Runway mishap



photo of Lockheed-SP-2H-Neptune-N4692A
accident date: 15-06-2014
type: Lockheed SP-2H Neptune
registration: N4692A


This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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