{"as_of":"2026-11-02","attribution":"FAA and NTSB data via eFlight Registry (https://eflight.com)","connections":[{"group":"Fitted to","items":[{"count":1,"name":"Waco ASO","note":"","unit":"with this engine series","url":"https://eflight.com/models/waco/aso"}],"relation":"powers"},{"group":"Where they are","items":[{"count":1,"name":"Ohio","note":"","unit":"of these aircraft","url":"https://eflight.com/states/OH"}],"relation":"registered in"},{"group":"Airworthiness","items":[{"count":1,"name":"Failure reports on the Jacobs L-4MB","note":"","unit":"reports since 1995","url":"https://eflight.com/engines/jacobs-l-4mb#airworthiness"}],"relation":"subject to"},{"group":"Analytics","items":[{"count":null,"name":"The fleet by engine type","note":"","unit":"","url":"https://eflight.com/analytics/fleet"},{"count":null,"name":"Every engine series","note":"","unit":"","url":"https://eflight.com/engines"}],"relation":"compared in"}],"graph":"https://eflight.com/graph","graph_index":"https://eflight.com/graph/index.json","license":"https://creativecommons.org/licenses/by/4.0/","node":{"aircraft":1,"horsepower":245,"id":"jacobs-l-4mb","maker":"Jacobs","name":"Jacobs L-4MB","thrust_lb":null,"type":"Piston (reciprocating)","url":"https://eflight.com/engines/jacobs-l-4mb"},"source":"FAA Civil Aviation Registry, FAA airport file, NTSB accident database; assembled by eFlight Registry"}