{"as_of":"2026-11-06","attribution":"FAA and NTSB data via eFlight Registry (https://eflight.com)","connections":[{"group":"System","items":[{"count":null,"name":"Heating, ice protection and utility systems","note":"","unit":"","url":"https://eflight.com/systems/utility"}],"relation":"about"},{"group":"More","items":[{"count":null,"name":"Every FAA order","note":"","unit":"","url":"https://eflight.com/directives"},{"count":null,"name":"Every aircraft system","note":"","unit":"","url":"https://eflight.com/systems"}],"relation":"see also"}],"graph":"https://eflight.com/graph","graph_index":"https://eflight.com/graph/index.json","license":"https://creativecommons.org/licenses/by/4.0/","node":{"effective":"","faa_document":"https://drs.faa.gov/browse/excelExternalWindow/30236AD133D55BF186256A56006E200E.0001","id":"47-21-09","kind":"AD","name":"Airworthiness directive 47-21-09","published":"","subject":"Hydraulic System Modifications","system":"utility","type":"directive","url":"https://eflight.com/directives/47-21-09"},"source":"FAA Civil Aviation Registry, FAA airport file, NTSB accident database; assembled by eFlight Registry"}