     UCASE(`aircraft-damage`), # aircraft-damage
     WordCase(`air-carrier`), # operator
     IF(INSTR(`far-desc`, ':') = 0, # far-desc
-       UCASE(`far-desc`),
+       NULLIF(UCASE(`far-desc`), 'UNKNOWN'),
        TRIM(SUBSTRING(UCASE(`far-desc`) FROM INSTR(UCASE(`far-desc`), ':') + 2))),
     NULL, # pilot-certification
     NULL, # pilot-total-hours

    NULL, # engine-type
    UCASE(`aircraft-damage`), # aircraft-damage
    WordCase(`operator`), # operator
    UCASE(`flight-conduct-code`), # far-desc
    UCASE(`pilot-certification`), # pilot-certification
    `pilot-total-hours`, # pilot-total-hours
    `pilot-make-model-hours`, # pilot-make-model-hours

    OR `country` IS NULL);
DELETE FROM `events-ntsb` WHERE `country` <> 'United States' OR `country` IS NULL;

UPDATE `events-ntsb` SET `injuries-fatal` = IFNULL(`injuries-fatal`, 0),
  `injuries-serious` = IFNULL(`injuries-serious`, 0), `injuries-minor` = IFNULL(`injuries-minor`, 0),
  `uninjured` = IFNULL(`uninjured`, 0) WHERE NOT (`injuries-fatal` IS NULL AND `injuries-serious` IS NULL AND
