Change 1 to airport operations manual. 

 - [Washington, D.C.,  1981]. 
 - v. 
<br/><br/> 3/24/81.  CRDP Program Historic Shelflist record. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Airports--Safety regulations--United States.
<br/><br/><label>GPO Item No.: </label>0431-A-27 
<br/><br/><label>Gov. Doc. Class. No.: </label>TD 4.8/5:150/5280-1/CH.1