The Little Route That Couldn’t: The Short Life of the Minneapolis to Duluth CAM 9 Spur

Dr. Bruce Arlen Wasserman

In May 1931, the U.S. economy was entrenched in the Great Depression, with widespread poverty, a high rate of unemployment, deflation—which caused a near-collapse of the farm sector—and labor unrest. Many consider this to be one of the darkest periods of American economic history. It was in the middle of these conditions that the CAM 9 (Contract Air Mail 9) spur route from Minneapolis to Duluth was born. 

But before that birth, a lot of activity took place at the dawn of Contract Air Mail in the United States that established CAM 9 service. The Kelly Act of 1925, otherwise known as the Air Mail Act, was passed on February 2, 1925, allowing the United States Post Office Department (USPOD) to contract with private companies to carry mail, moving the operation of air mail services away from the government. This start of Contract Air Mail service marked a significant milestone and was key to the birth of commercial aviation in the United States. CAM 9’s first flight—from Chicago to the Twin Cities of Minneapolis and St. Paul, Minnesota and return—took to the air on June 7, 1926. With stops at Milwaukee and La Crosse, Wisconsin for both the westbound and eastbound flights, the route serviced not only the terminal cities but points in between. 

The CAM 9 service route was originally operated by Chicago’s Charles “Pop” Dickinson, a wealthy, retired Chicago seed dealer turned pilot, aviation patron, and jack of all trades, who had successfully bid to be awarded the contract with his startup company, Dickinson Air Lines (Figure 1). Working for him were six pilots. Dickinson had three Laird Biplanes powered by Wright J-4 engines (Figure 2), two planes built by Partridge, Inc, a tiny manufacturer and flight school in Chicago run by one of Dickinson’s pilots, and an unspecified plane supplied by another pilot. The CAM 9 contract was a critical piece in the transportation of mail across the country. According to The Valdosta Daily Times in their June 7, 1926 edition, “Chicago is now the terminus of five interstate routes: “the Transcontinental, Chicago-Dallas, Chicago-Detroit, and the new Northwest leg, which was begun today.” The “Northwest leg” they mentioned was the CAM 9, Chicago-Minneapolis/St. Paul route. This key contract enabled mail to transit from Minneapolis to New York, via Chicago, in only fifteen hours.

The westbound Chicago to Minneapolis-St. Paul leg of the inaugural flight, according to The Green Bay Press Gazette, departed at 6:13 a.m. piloted by Dan Keiser, in less-than-ideal weather conditions. Eleven minutes later, Pilot Charles Emil “Nimmo” Black took off with a heavy load of mail, followed by a third plane, piloted by H.J. Keller. Kiser was forced down by heavy winds near Rio, Wisconsin. His mail was picked up by Henry Keller, who suffered a broken gas line near La Crosse, underwent repairs, and arrived in Minneapolis on the morning of June 8. Black—scheduled to fly directly from Chicago to St Paul—had to make an emergency fuel stop in La Crosse because of the heavy headwinds. While on the ground, mail from La Crosse intended for St. Paul was also loaded onto his plane. Despite these problems, the westbound mail destined for Minneapolis and St. Paul eventually arrived. 

Eastbound on June 7, Pilot Elmer Partridge—one of the two pilots carrying the mail from Minneapolis to Chicago—crashed right after takeoff. Partridge weas killed in the crash.  The June 8 Fort Worth Record–Telegram, City Edition, wrote: 

Buffeted about in the clouds by a driving gale from the northwest, Elmer Partridge, Chicago Pilot, flying a southbound plane from the Twin Cities, fell to his death near St. Paul. His plane was unable to withstand the elements… A farmer said the pilot was flying comparatively low when two pieces, presumably parts of the machine, fell from the plane after which it went into a nose dive, apparently partly righted itself, then tipped sideways and crashed… Dickinson blamed the flyer’s death to the recent rule which assesses a fine on all air mail pilots late with their cargoes and said Partridge was trying to make schedule time although it was unsafe to fly. 

But the Bureau of Aircraft Accidents Archives report doesn’t mention the loss of parts from Partridge’s plane, as noted by the eyewitness, in the gale-force winds recorded that day. Instead, they state:

The pilot named ‘Partridge’ was performing this first mail flight (route CAM-9) from Minneapolis to Chicago. This was the inaugural flight. Shortly after takeoff from Minneapolis-World Chamberlain Field, while climbing, the aircraft went out of control and crashed in Mendota, east of the airport. The pilot was killed, and the aircraft was destroyed. As result of this accident, the traffic was suspended on the evening of 07JUN1926.

The mail from Partridge’s plane was transferred to rail, arriving in Chicago the next morning and receiving a backstamp of 8:30 or 9:00 a.m. Figure 3 shows the front of a crash cover that exhibits a magenta cachet, with a time and date stamp of 2:10 p.m. June 7. Figure 4 shows the cover’s reverse, with the Chicago receiving mark of June 8 at 8:30 a.m. Partridge’s plane was transporting 170 pounds (around 2,700 pieces) of mail at the time of his crash. Because of the crash, all other eastbound mail from St. Paul—except that mail already loaded on the second eastbound plane piloted by William Brock—was sent directly to Chicago via rail. Brock successfully delivered his load of mail to Chicago on June 7 after stops to pick up more mail at La Crosse and Milwaukee. A cover carried by Brock is shown in Figures 5 and 6, with an arrival stamp of 11:00 p.m., June 7, while Figures 7 and 8 show a cover—originally on Partridge’s plane— that missed Brock’s plane and was sent by train from St. Paul and received in Chicago at 11:00 a.m. on June 8. Note the lower left corner card on the cover for the “Port of Saint Paul,” listed as the “Gateway to the Great Northwest by land, water and air,” as well as the insert card, shown in Figure 7, that heralds the “First Air Mail Flight on the St. Paul to Chicago Line.”

After the tragedy of Partridge’s crash, “Pop” Dickinson—that same day— terminated his participation as the CAM 9 contractor and his pilots never made another mail flight on the route. On August 16 he gave the Post Office Department a 45-day notice that he was suspending operations because of safety concerns. Following the suspension, the USPOD again advertised the route and Northwest Airways (NWA)—formed on September 1, 1926, in Minneapolis by a group of local investors specifically to operate the CAM 9 route—was named the new carrier. The company operated from Speedway Field, now a part of the Minneapolis-St. Paul International Airport. Their first day of operations on the route, using open cockpit biplanes, was October 1, 1926 (Figure 9). In 1928, NWA loaded their first mail onto their new Ford Trimotor airplane, serial number (SN) NC7416. A photograph of that event was taken (Figure 10) and is also this issue’s cover. 

A little more than a year later, on June 24, 1929, that same plane was involved in NWA’s first crash. Flown by Capt. Edwin Middagh, an experienced pilot with over 4,000 flying hours, the plane took off in calm air. As it cleared the field and headed south, the starboard engine stopped, followed in quick succession by the center and port engines. To save the passengers and crew, Middagh swung the aircraft back for an emergency landing. Unfortunately, the Trimotor didn’t have enough power or lift and the aircraft crashed, clipping two houses on the way down. The Trimotor broke into three pieces (Figures 11 and 12). The flight’s steward was able to kick out a window and emerged unscathed. The pilot was knocked unconscious and as the steward and bystanders tried to extract him from the wreckage, the plane caught fire and the pilot burned to death. All the passengers escaped but they suffered various injuries. Four bystanders received burns while attempting to rescue the pilot, and a resident was injured by falling debris. Figure 13 shows a local newspaper’s story about the accident.

Fast forward to 1931: NWA had successfully operated CAM 9 flights for five years, expanding the route with an additional spur to Madison, Wisconsin and a spur from Milwaukee to Green Bay, Wisconsin. They added a stop in Rochester, Minnesota on the Chicago to Minneapolis route and they later added a spur route from Minneapolis to Pembina, North Dakota with a connection to Winnipeg, Manitoba, Canada, as well as running night flights between Minneapolis and Chicago. With all the expansion that NWA created around their CAM 9 contract, it would not have been surprising to hear that on May 30 they added a spur route to Duluth, Minnesota, if that event had not occurred smack dab in the middle of the worst economic crisis the United States had ever experienced—the Great Depression. 

In 1931, Duluth was a significant industrial hub known for its shipping, steel production, and railroads. It had a population of over 100,000, making it the third-largest city in Minnesota. But the Great Depression had profound effects on Duluth’s economy. Key industries, including shipping and steel, experienced significant downturns and unemployment soared to around 25 percent. For residents in some parts of Minnesota—the Iron Range, for example—the unemployment rate hit 70 percent. Between 1929 and 1933, the average family in the United States saw its income drop by more than one third. Prices for everyday commodities also dropped in the Great Depression because fewer people could afford to buy essentials, but farmers still had to sell their own production regardless of market prices, which essentially caused the farm sector to severely contract. From the late 1920s to the 1930s, the price of a gallon of milk, for instance, dropped nearly 10 cents to 26 cents a gallon. In 1931, eggs were 15 cents a dozen, a one-pound loaf of bread was 12 cents, and a whole fryer chicken cost 35 cents. 

Compare that with the cost to send a letter in 1931: a one-ounce letter via surface from Minneapolis to Duluth was two cents, whereas the same letter via CAM 9 airmail was five cents. Given that unskilled laborers earned around 45 cents an hour, the three-cent cost premium for airmail was significant. In addition to receiving an airmail subsidy from the federal government, NWA may have been motivated to add the new spur route due to the large population in Duluth. Perhaps they guessed the national economic depression was nearly over and they wanted to be the company remembered as providing airmail service when times were tough and earnings were limited. These speculations may be true, but the new spur to Duluth had another, very significant barrier—in 1931 Duluth didn’t have a commercial airfield. Their nearly new Williamson–Johnson Municipal Airport, dedicated in 1930 (Figure 14), featured two sod runways, each around 2,600 feet long. These unpaved and relatively short runways were suitable for smaller aircraft but were dangerous for the larger, heavier planes NWA would fly there. 

Ultimately, the company chose the quickest solution to create adequate runway space in Duluth… Lake Superior. And to facilitate this shift in landing surfaces for their new CAM 9 spur, in May 1931 the company added two Sikorsky S-38B amphibious flying boat aircraft to their fleet (Figures 15, 16, and 17). The Sikorsky S-38B was used extensively in the early 1930s for both passenger and airmail services. Known as the “Explorer’s Air Yacht,” the S-38B was favored for its reliability and robust performance. The planes had two, 450 hp Pratt & Whitney R-1340 Wasp radial engines. They could cruise at 105 mph and had a maximum speed of 120 mph, with a range of 500 to 700 miles and a ceiling of 12,500 feet. The planes each held two crew and eight passengers, as well as 1,000 pounds of cargo. 

On the inaugural first flight from Minneapolis-St. Paul to Duluth, Pilot Jerome Sparboe left at around 9:00 a.m. with 20 pounds (around 320 pieces) of mail. The cachets for this flight were provided by NWA and consisted of a rubber-stamped outline of the State of Minnesota, with the words “First Flight / A.M. 9 Air Mail / Twin Cities to Duluth, Minn. / Cachet by Northwest Airways, Inc. / May 30, 1931.” The points of St. Paul, Minneapolis, and Duluth were illustrated in a simple line drawing map. Figures 18 and 19 show the front and back of one of these covers, mailed from Minneapolis with this cachet, on an envelope marked as “approved” by the USPOD, whereas Figure 20 shows a cover mailed from “Saint Paul” at the same date and time with the same cachet and a circular date stamp indicating “Air Mail.”

CAM 9 spur flights departed from St. Paul’s Holman Field—named after NWA’s first pilot, Charles “Speed” Holman—which served as NWA’s operations base. The S-38B’s amphibious capabilities allowed them to take off from a runway and land on the water of Lake Superior. Northwest Airways used the Duluth Boat Club, located on Minnesota Point, as the place where mail and passengers would disembark and a new load of mail and passengers traveling south would be brought to the plane for the return trip. Minnesota Point was near the Duluth Ship Canal and adjacent to the Aerial Lift Bridge. It provided calmer waters for the planes to moor and for maintenance. Incoming flights would taxi through the Ship Canal and tie up at the Boat Club pier. All told, the time in the air from Minneapolis to Duluth was around 80 minutes, with a similar time for the return flight. 

For the inaugural return flight, Sparboe departed at 4:00 p.m. with 297 pounds (around 4700 pieces) of mail from Duluth. The rubber-stamped official cachet, approved by the USPOD, shows Duluth’s Aerial Lift Bridge with the caption “First Flight Air Mail / Duluth Minnesota May 30, 1931 / Route AM 9 • P.O.D.” Figures 21 and 22 show the front and back of a return flight cover. Though the cover shown received a 4:00 p.m. May 30 postmark in Duluth, the receiving Minneapolis General Delivery backstamp was not applied until May 31. This cover was addressed to Frank Herget care of General Delivery, a philatelist and stamp dealer in Buffalo, NY. during the early to mid-twentieth century. A document listed in the archives of the American Numismatic Association calls him a “Purveyor of Stamps.” Herget was associated with numerous FDCs, such as a 1929 two-cent Nebraska overprint with a self-made cachet addressed to him, sold in a 2009 Cherrystone auction. 

Among the mail Sparboe carried was a commercial cover with the official Duluth First Flight Cachet, addressed to Colonel Paul Henderson and mailed by Northwest Airways, Inc from their headquarters in St. Paul. It traveled north on the first flight to Duluth before receiving a cancellation in Duluth for the return flight (Figures 23 and 24). It exhibits both a First Flight Minneapolis-St. Paul to Duluth official NWA cachet on its reverse, as well as the Duluth official cachet on its front. The Chicago receiving mark on the cover’s reverse indicates it traveled to Chicago via the main CAM 9 route after arriving in St. Paul. The front indicates the cover was redirected to Washington, DC.

Colonel Henderson was a pivotal figure in the development of early U.S. airmail and commercial aviation. He served as the Second Assistant Postmaster General from 1921 to 1922 and played a role in transitioning the Airmail Service from using Post Office pilots to Contract Air Mail. He later became President of National Air Transport (NAT), an early CAM contractor. NAT would eventually be absorbed by United Airlines. As Second Assistant Postmaster General, Henderson helped establish overnight air mail service. He directed the installation of powerful rotating beacons along the transcontinental route to guide pilots in the dark, modeling the system after an experimental lighted airway the Army had created in Ohio.

When NWA took on the CAM 9 spur route, the USPOD was paying the airlines $2.75 per pound of mail transported in either direction as a “Mail Subsidy” between the Duluth and the Minneapolis-St. Paul points of the route. NWA augmented those fees with passenger transport in their eight-passenger amphibious planes. But in 1933, the U.S. government implemented significant reductions in airmail subsidies as part of broader economic measures enacted during the Great Depression. The Senate struck $19 million from the Post Office Appropriation Bill for the 1933-34 fiscal year, creating a substantial decrease in funds available to allocate for airmail services. In their February 13, 1933 issue Time Magazine wrote, “Vexed by the Senate’s action, airmail contractors were not shocked.” Due to those reductions, NWA discontinued several routes, including their Fox River Valley route to Green Bay and stops at Madison, Wisconsin. 

The Railway Mail Service (RMS) was a pivotal component of the U.S. postal system in the 1930s. Specialized Railway Post Office (RPO) cars were equipped on passenger trains, where postal clerks sorted mail en route. This allowed for direct mail exchange at various stops. Because the St. Paul Union Depot was the third busiest mail processing and distribution center in the country, the speed—and lower cost—of the route’s RMS began to bury NWA’s CAM 9 spur route. The frequency of rail scheduling and RMS operations ensured that mail between Minneapolis–St. Paul and Duluth was transported efficiently, a tremendous disincentive for the public to pay for premium, air mail service. Figure 25 shows a cover marked to be sent via Air Mail between Duluth and Minneapolis on October 31. Due to NWA’s cancelation of their spur route on that day, “Air Mail” was crossed out and the letter was instead sent by Railway Mail Service, Special Delivery. Note that the cover has underpaid the Special Delivery and surface mail fees, which totaled eighteen cents, by five cents.

Because unemployment was still at an all-time high and wages and farm earnings were at an all-time low, the extra cost of airmail in the Great Depression when most people struggled to make ends meet, wasn’t offset by its slightly quicker service. The Duluth CAM 9 spur route was terminated by Northwest Airways on October 31, 1933 due to the government’s subsidy reduction, as well the unfortunate but entirely predictable ongoing lack of demand for airmail services during the Depression. Northwest Airways sold off their two Sikorsky S-38Bs, finalizing the burial of the little route that couldn’t be kept alive during those tumultuous times. 

Bruce Arlen Wasserman received an MFA from Vermont College of Fine Arts in 2017 and is the editor of The Airpost Journal, a nonfiction magazine focused on aviation history. His poetry manuscript, The Broken Night, was published by Finishing Line Press in 2022. He has been a literary critic for the New York Journal of Books, has been nominated for a Pushcart Prize, was a semi-finalist for the Francine Ringold Awards for New Writers, a semi-finalist for the Proverse Prize and won the Anna Davidson Rosenberg 2019 Poetry Award. Bruce’s writing has been published in the Proverse Poetry Prize Anthology, The Fredericksburg Literary and Art Review, The River Heron Review, Kindred Literary Magazine, the Broad River Review, Cathexis Northwest Press, High Shelf Literary Magazine, Wild Roof Journal, the New York Journal of Books, the Washington Independent Review of Books, The American Philatelist and The Airpost Journal, among others.