{"as_of":"2026-11-06","attribution":"FAA and NTSB data via eFlight Registry (https://eflight.com)","connections":[{"group":"Applies to","items":[{"count":1315,"name":"Piper PA-23 Apache and Aztec","note":"","unit":"registered","url":"https://eflight.com/models/piper/pa-23#airworthiness"}],"relation":"applies to"},{"group":"System","items":[{"count":null,"name":"Flight controls","note":"","unit":"","url":"https://eflight.com/systems/flight-controls"}],"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/397E2BF0ADB873888625698B00764ED0.0001","id":"57-21-01","kind":"AD","name":"Airworthiness directive 57-21-01","published":"1958-01-23","subject":"Rudder Trim Tab Pin","system":"flight-controls","type":"directive","url":"https://eflight.com/directives/57-21-01"},"source":"FAA Civil Aviation Registry, FAA airport file, NTSB accident database; assembled by eFlight Registry"}