Serious incident Dassault Falcon 20 N175GA, Tuesday 4 April 2000

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Date:	Tuesday 4 April 2000
Time:	17:24 LT
Type:	Dassault Falcon 20
Owner/operator:	Grand Aire Express, Inc.
Registration:	N175GA
MSN:	45
Total airframe hrs:	16552 hours
Engine model:	GE CF-700-202
Fatalities:	Fatalities: 0 / Occupants: 2
Other fatalities:	0
Aircraft damage:	Minor
Category:	Serious incident
Location:	Opa Locka, FL - United States of America
Phase:	Approach
Nature:	Ferry/positioning
Departure airport:	Louisville, KY (KSDF)
Destination airport:	Opa Locka, FL (KOPF)
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
According to the PIC, when the landing gear selector was positioned to the gear down position in preparation for landing, the landing gear did not extend and cockpit indications confirmed not down. A go around was executed and 'Procedure A' of the 'Emergency Gear Extension' checklist was executed. The result was a down and locked indication of the nose gear and the right main gear, no indication of the left gear being down, both hydraulic system quantities started decreasing, and control pressures felt in the yoke/stick indicated that the flight controls were losing their boost. The PIC elected to declare an emergency with the tower and execute a 2 gear down/1 gear up landing instead of completing the 'Procedure B' and 'Procedure C' portions of the checklist. The aircraft swerved off the left edge of the runway and sustained minor left under-wing skin scraping and a puncture to the left wing droop. Examination of the left wheel well revealed the malfunction causing the double hydraulic system leakage was the failure of two bolts attaching the hydraulic emergency slide valve to the left gear door actuating cylinder. Dassault Falcon Jet Service Bulletin FJF 32-160 dated April 26, 1984, recommends replacement of the 4-mm bolts with 5-mm bolts, to be accomplished, 'when the components are returned for major overhaul or repair, or upon request'. The incident aircraft had not undergone accomplishment of Service Bulletin FJF 32-160.

Probable Cause: The failure of the PIC to execute the complete procedure for emergency extension of the landing gear and the subsequent landing with the left main landing gear not locked fully down, resulting in an excursion off the runway and collision with a runway stanchion. A factor in the incident was the fatigue failure of the left MLG door hydraulic emergency slide valve bolts due to non-compliance with a 1984 factory service bulletin that recommended replacement with larger bolts.

Accident investigation: