{"as_of":"2026-10-07","attribution":"FAA and NTSB data via eFlight Registry (https://eflight.com)","connections":[{"group":"System","items":[{"count":null,"name":"Airframe structure","note":"","unit":"","url":"https://eflight.com/systems/structure"}],"relation":"about"},{"group":"Related orders","items":[{"count":null,"name":"Replaced by 98-21-21 R1","note":"","unit":"","url":"https://eflight.com/directives/98-21-21 R1"}],"relation":"related to"},{"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":"1998-10-30","faa_document":"https://drs.faa.gov/browse/excelExternalWindow/840516F968F93E2286256A0A006E06BD.0001","id":"98-21-21","kind":"AD","name":"Airworthiness directive 98-21-21","published":"","subject":"Inflatable Door Seals","system":"structure","type":"directive","url":"https://eflight.com/directives/98-21-21"},"source":"FAA Civil Aviation Registry, FAA airport file, NTSB accident database; assembled by eFlight Registry"}