{"as_of":"2026-11-06","attribution":"FAA and NTSB data via eFlight Registry (https://eflight.com)","connections":[{"group":"Applies to","items":[{"count":817,"name":"Robinson R22","note":"","unit":"registered","url":"https://eflight.com/models/robinson/r22#airworthiness"}],"relation":"applies to"},{"group":"System","items":[{"count":null,"name":"Rotorcraft systems","note":"","unit":"","url":"https://eflight.com/systems/rotorcraft"}],"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":"1980-12-18","faa_document":"https://drs.faa.gov/browse/excelExternalWindow/FDB6540CE7F346AD86256A4E0046EE1E.0001","id":"80-21-53","kind":"AD","name":"Airworthiness directive 80-21-53","published":"","subject":"Main Transmission Gears","system":"rotorcraft","type":"directive","url":"https://eflight.com/directives/80-21-53"},"source":"FAA Civil Aviation Registry, FAA airport file, NTSB accident database; assembled by eFlight Registry"}