PAN AM IN FEBRUARY 1935
90 Years Ago Series
Photo compilation: RKO Logo with Sikorsky S-42 insert & S-42 cutaway showing interior of the plane.
"Transmitter" production logo of RKO Radio Pictures 1929-1957, Frank Ross productions Ltd. (Wikipedia via Library of Congress Conservation Center. https://commons.wikimedia.org/wiki/File: RKO_Radio_Pictures_transmitter_ident.jpg). Sikorsky S-42 in flight/ insert & Sikorsky S-42 cutaway (Pan Am Historical Foundation Collection).
“The Way Home”
by Eric H. Hobson, Ph.D.
February-March-April 1935’s Pan American Air Ways announced,
“an ocean-spanning wireless direction-finder capable of guiding air liners across the broad stretches of either the Pacific or the Atlantic, has been accomplished by engineers of the Pan American Airways System … differing completely from theories heretofore held by communications engineers as to the possibility of converting short-wave transmission for consistent direction finding over long ranges.”
PAA’s design team led by Chief Communications Engineer, Hugo Leuteritz, had tweaked Adcock-type direction finder (DF) system for years. In the past two they stretched the ability to maintain contact with aircraft from 600 miles to 1,800 miles. One test tracked a PAA S-38 1,000 miles east to west along the Amazon River from Belem to Manaus, Brazil, 2100 miles from Miami.
Readers learned,
“Two stations … by overlapping their range, can cover a distance between New York and London. Within that range these two stations are capable of standing constant guard over an airliner crossing either ocean by taking bearings on the ship in flight and thus guiding it on a control course regardless of wind or weather conditions.”
That reassurance of a “constant guard” resonated with families of flight crews working in 1935 to open the new transpacific route and of crews that would maintain the route starting in 1936. This advanced guidance system would bring their husbands, lovers, sons, and nephews home. The Pacific Ocean’s vastness was now a bit less foreboding.
Navigators on the Sikorsky S-42s, Martin M-130s, Boeing B-314s flying the Pacific did not bet their lives on the system, however, even as it improved incrementally.
Horace Brock’s assessment was succinct.
“Adcock ranges for long-range bearings which were supposed to give accurate bearings … did not. The famous Pan Am long-range radio bearings system was perhaps better than nothing, but not much better.” “The Adcock (A-N) ranges on the Pacific Islands” were known to give “a false `on course’ indication. It might be fatal to rely on them. We didn’t. They only served as a check on the celestial navigation.”
Another decade would pass before more-reliable guidance systems supplanted this much heralded, yet rudimentary, system.