{"as_of":"2026-10-30","attribution":"FAA and NTSB data via eFlight Registry (https://eflight.com)","connections":[{"group":"Fitted to","items":[{"count":1,"name":"Bucker-Jungman 131","note":"","unit":"with this engine series","url":"https://eflight.com/models/bucker-jungman/131"}],"relation":"powers"},{"group":"Where they are","items":[{"count":2,"name":"Florida","note":"","unit":"of these aircraft","url":"https://eflight.com/states/FL"},{"count":1,"name":"Kansas","note":"","unit":"of these aircraft","url":"https://eflight.com/states/KS"}],"relation":"registered in"},{"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":3,"horsepower":100,"id":"hirth-hm-504","maker":"Hirth","name":"Hirth HM 504","thrust_lb":null,"type":"Piston (reciprocating)","url":"https://eflight.com/engines/hirth-hm-504"},"source":"FAA Civil Aviation Registry, FAA airport file, NTSB accident database; assembled by eFlight Registry"}