Pilot Debrief

CESSNA T210M near Napa, CA — 2023-08-21

Final reportWPR23LA321
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Date
2023-08-21
Location
Napa, CA, USA
Airport
APC
Aircraft
CESSNA T210M
Registration
N6535B
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Climb

Probable cause

Insufficient hydraulic pressure to the landing gear system following the completion of the emergency gear extension checklist, which resulted in the main landing gear collapsing during landing. Contributing to the accident was a loss of electrical power for reasons that could not be determined based on available evidence, which resulted in a failure of the normal landing gear extension system.

Contributing factors

Contributing to the accident was a loss of electrical power for reasons that could not be determined based on available evidence, which resulted in a failure of the normal landing gear extension system.

NTSB narrative

The pilot was flying the airplane to an airport where the annual inspection was to be performed. During climb out, the airplane sustained a total loss of electrical power. The pilot elected to return to the departure airport, and during the return, she was able to regain communication on one radio. The pilot followed the emergency landing gear extension checklist and attempted to manually apply hydraulic pressure to extend the landing gear. However, she could not verify that the landing gear was fully extended and locked due to the electrical failure. She reported that she pumped the manual handle up and down over 55 times (cycles) and felt the handle was stiff when she stopped pumping. The pilot flew a visual approach to land and, while on the base leg, tower personnel told her the gear appeared to be down. The pilot continued the approach, and during landing, both main landing gear collapsed, resulting in the airplane exiting the runway and striking a fence and brush. The owner of the airplane did not respond to investigator inquiries, and disposed of the airplane before an examination could be completed. As a result, the reason for the electrical failure that precipitated the landing gear collapse could not be determined. The Landing Gear Failure to Extend checklist directs the pilot to pump the emergency hand pump “until resistance becomes heavy - about 65 cycles,” and contains a note that indicated, “It takes about 55 cycles (110 strokes) to extend the gear.” The accident is consistent with the landing gear not extending normally following a loss of electrical power, and subsequently was not locked in the down position following completion of the emergency gear extension checklist. Although the pilot pumped the emergency gear extension handle the minimum recommended times, the pressure created was likely insufficient to ensure the landing gear were fully extended and locked in the down position, which resulted in the main landing gear collapsing during landing.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have aborted the flight after electrical failure during climb.

NTSB coding

Evidence available

  • Photos
  • 7 docket documents
View NTSB final reportView NTSB docket

Docket documents7

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