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ASN Wikibase Occurrence # 225687
Last updated: 1 June 2019
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Date:11-FEB-2018
Time:12:58
Type:Shanks V Roger VARI EZE
Owner/operator:Private
Registration: N944X
C/n / msn: 893
Fatalities:Fatalities: 0 / Occupants: 2
Other fatalities:0
Aircraft damage: Substantial
Category:Accident
Location:Santa Monica, CA -   United States of America
Phase:
Nature:Private
Departure airport:LA VERNE, CA (POC)
Destination airport:Santa Monica, CA (SMO)
Investigating agency: NTSB
Narrative:
The private pilot reported that, during the landing roll, the experimental amateur-built airplane experienced a partial loss of right brake effectiveness. The pilot attempted to counter the directional control imbalance as the roll continued, but he became concerned that the airplane might run off the end of the runway and the drop-off at the end, so he applied maximum brake pressure. The airplane then veered left, departed the runway, and impacted a hangar.

Postaccident examination revealed that a slow fluid leak had developed at the inlet fitting of the right brake caliper, and the fluid level in the reservoir for the right brake master cylinder had dropped to just under half of its capacity. This leak most likely allowed air to be introduced into the system either through the fitting or the depleted brake reservoir, which resulted in reduced effectiveness of the right brake. Maintenance records indicated that the pilot replaced the hydraulic lines on the right side about 147 flight hours before the accident.

The airplane was equipped with a free-castering nosewheel and ground steering was accomplished through differential braking once rudder effectiveness diminished at lower speeds. Therefore, with the loss of braking effectiveness on one side, the pilot had limited means to effectively slow the airplane and maintain directional control once the airplane decelerated to a speed below which rudder authority was available.

Probable Cause: An undetected fluid leak in the right brake line, which resulted in a reduction of braking effectiveness at the right wheel and a loss of directional control during the landing roll.

Sources:

NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20180211X21608&key=1

Accident investigation:
cover
  
Investigating agency: NTSB
Status: Investigation completed
Duration: 1 year and 3 months
Download report: Final report


Revision history:

Date/timeContributorUpdates
01-Jun-2019 07:28 ASN Update Bot Added

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