Sometimes when I am looking into the background of an accident, I keep finding more and more intriguing details, rabbit holes of interesting information, until I’m barely sure anymore what it was I wanted to know in the first place.

It’s well known that commercial aviation got its start in the aftermath of the First World War but, when I started looking in a small Miami airline called Chalk’s Ocean Airways, I was surprised to find it had an incredible history. This small airline was possibly the world’s first international scheduled airline service and definitely the longest continuously operated airline in the world until it was shut down in 2007. KLM was founded six months later and now holds that record.

The founder was Arthur Burns “Pappy” Chalk, a mechanic and barnstormer from Paducah, Kentucky. His aviation career began when he met Tony Jannus, an early aviationist. Jannus became a test pilot for the Benoist Aircraft Company and achieved many aviation firsts with their ground-breaking biplanes and flying boats, including an overwater flight record in a Benoist biplane, flying 1,900 miles (3,058 km) from Omaha, Nebraska to New Orleans, Louisiana by following the MIssouri and Mississippi Rivers.

A Florida businessman was impressed by this flight and came up with the idea of offering commercial passenger flights in Florida, between Tampa and St Petersburg, crossing the Tampa Bay. At the time, travelling between the two cities was a slow steamship ride across the bay or a meandering five-hour journey by rail. It took even longer by car (or worse, horse and buggy) on the unpaved roads.

The businessman got financial support and the support of the community leaders and, at the end of 1913, Benoist was contracted to supply two daily round trips, creating the world’s first scheduled airline: the St. Petersburg–Tampa Airboat Line. The first passenger ticket was auctioned for $400 and Jannus flew the inaugural flight. At the end of the scheduled service, Jannus left Benoist to become a test pilot for Curtiss Aeroplane Company. In 1915, Curtiss sent Jannus to to Russia to be the company’s test pilot and trainer of Russian combat pilots. He died in October 1916, when his Curtiss H-7 crashed into the Black Sea after engine problems.

But the point here was that Chalk met Jannus in 1911, after Jannus developed engine trouble in a Benoist flying boat and made a forced landing in the Ohio River. Chalk worked for the Kentucky Auto Mechanic Co. and offered fix Jannus’ engine in return for flying lessons, which Jannus agreed. Chalk spent a few years barnstorming around the southern US, selling plane rides and performing stunts. After a few years, perhaps inspired by Jannus, Chalk moved to Miami where he offered sightseeing flights and flying lessons in his three-seater Curtiss HS-2L. In 1917, he started Red Arrow Flying Service but suspended operations to fly with the army when the US entered World War I. After the war, he returned to Miami to restart his flying business. He renamed the airline Chalk’s Flying Service and began offering scheduled sea-plane flights between Miami and Bimini in the Bahamas in February 1919.

Pappy Chalk initially sold tickets from his “office” – a chair and umbrella on Miami Beach. The reservations line was a crank telephone nailed to a pole and the terminal was the dock at the Royal Palm Hotel. Chalk did all the flying himself and hired staff at Bimini to carry passengers piggyback to the shore. By now, the United States had gone dry in the grips of the prohibition and Chalk’s passengers included rumrunners and lawmen.

90 Years of Chalk’s on Historic Wings

Chalk’s found itself frequently operating with small profits and had to find creative ways to supplement its income. For example, during the years of prohibition in the USA, Chalk’s quietly become the premiere smuggling operation for illegal alcohol imports from the Bahamas to Miami. Even if the authorities found out about it, it seemed that Chalk’s was able to continue flying — at considerable profits, even if under the table.

Around the same time, the shipping channel between Miami and Fisher Island was deepened and the sand and debris dredged up was left in a landfill about two miles east of Miami. The resulting man-made island, originally known as Causeway Island, was deeded to Miami, with the restriction that it could only be used for public or municipal purposes. It was renamed Watson Island (after the then mayor of Miami).

In 1926, Chalk moved his operations to Watson Island, establishing a sea-plane base which is still in use as Miami Seaplane Base (X44). The water runway is 15,000 feet long and oriented NW/SE. I’m amused that the charts specify Elevation Above Mean Sea Level as zero.

The airline continued to do well after the Prohibition ended in 1933, ferrying wealthy customers to the Bahamas but also becoming the airline of choice for connecting the residents of Bimini to Florida. Chalk’s Flying Service became famous: Ernest Hemingway, Errol Flynn, Ava Gardner, Judy Garland and Howard Hughes were among his regular clientele.

The US entered the war in 1941. The Grumman Aircraft Engineering Corporation had been supplying aircraft to the US Navy since 1930, when they developed the Grumman FF-1, a bi-plane fighter aircraft.

During the war, Grumman was probably best known for the F4F Wildcat and the F6F Hellcat, Navy fighter aircraft. But they also started developing amphibious aircraft: the Grumman J2F Duck biplane amphibian was in service with the US Navy from 1934, followed by the Grumman G-21 Goose and the Grumman G-44 Widgeon, which was also popular with the British Royal Navy’s Fleet Air Arm.

I have to admit, duck and goose and mallard were all clear to me but I had no idea what a widgeon was. In case you are also wondering, Wikipedia says that they are ‘dabbling ducks’ closely related to the gadwall and the falcated duck.

In any event, after the war came to a close, Grumman Aircraft wanted to expand their amphibious line for commercial use. They developed the Grumman Mallard, which had the same twin engines and high wings with underwing floats, but the new flying boat also sported a tricycle gear, a two-step hull and wingtip fuel tanks. The Grumman Mallard could carry two pilots and ten passengers and was designed for harbour-based city-to-city hops.

One of the (many) interesting aspects of the Grumman Mallard is that the design is based on what’s called a ‘wet wing’. Instead of fuel tanks in the wing, the fuel is stored in sealed off portions of the wing structure. This design saves on weight and allows more fuel to be carried for any given wing size. The joints around the tank seams are sealed to keep the wing box from leaking fuel.

Another aspect of the Mallard which was new to me is that the Mallard has a maximum zero fuel weight (MZFW).

The zero fuel weight (ZFW) is straight-forward: the total weight of the aircraft and all its contents, not including the useable fuel on board. So if the aircraft weight is 10,000 pounds and the weight of the fuel on board is 1,000 pounds, then the ZFW is 9,000 pounds. After 100 pounds of fuel has been used, the total weight has dropped to 9,900 pounds, where the weight of the remaining useable fuel is now 900 pounds. However, the zero fuel weight remains the same at 9,000 pounds. The point is that the total weight of the aircraft reduces but the zero fuel weight remains constant (although Wikipedia has just reminded me that obviously, if some part of the load is jettisoned in flight, the zero fuel weight can change in flight).

The maximum zero fuel weight (MZFW) is an airworthiness requirement: the maximum weight allowed before useable fuel is loaded.

Rather than using a simple weight calculation for the maximum take-off weight, the Grumman (and other large aircraft with cantilever wings) specifies a maximum zero fuel weight in order to optimise the maximum take-off weight without overloading the fuselage.

This has to do with where the fuel is carried in the wings. Lift on the wings (and the weight of the fuselage) bends the wing tips upwards and the wing roots downwards. However, the weight of the fuel in the wings bend the wing tips downwards, which can provide relief to the bending effect on the wing. So effectively, the capacity for extra weight in the wings is greater than the capacity for extra weight in the fuselage.

Grumman built 59 Mallards between 1946 and 1951. Most were purchased for corporate use but a few small air carriers used it as intended, including Chalk’s Flying Service. Initially, Pappy Chalk purchased a five-passenger Widgeon and a nine-passenger Goose; soon after, he purchased the first of several Mallards.

This Air & Space article on Chalk’s Ocean Airways describes flying in a Chalk’s Mallard.

To a passenger standing at its threshold, the Mallard seems more like an airplane than a boat. But when one steps into the craft, that step is down. So is the next one. Compared with the design of similar-sized landplanes, the door of the Mallard is set higher in the hull to keep out the water, and both the captain and the first officer sit at a higher level in order to see over the bow. With those first steps, plus the scent of salt air, the airplane’s second nature becomes apparent.

The Mallard’s interior reflects the middle years of powered flight—the cabin walls are painted, rather than covered with fabric, and you can count the rivet heads—but the seats are comfortable. Seating is catch as catch can. There’s no door to the cockpit, just an archway in the bulkhead, so you can look up at the pilot and first officer.

Now, not directly related (yet) but worth mentioning is that at the same time, aviation had shifted from a curiosity without much practical use to an industry. The demand for larger loads and better range was increasing every year. In 1956, the president of Pratt & Whitney Canada gave his his engineering manager 100,000 Canadian dollars to develop a turboprop engine to replace piston engines. The first engine was powered up and run successfully four years later, in February 1960, and first flew on a Beech 18 aircraft on the 30th of May 1961 at de Havilland Canada’s facility in Ontario. Full-scale production started in 1963.

Also in 1963, Grumman released a customer service bulletin about the maintenance and care of the Mallards. The wet wings were prone to fuel leaks as the fuel-tight seams began to open, a result of the normal flexing of the wing over time. They also were realising (25 years before Aloha Airlines flight 243) of the corrosive effects of salt water. Customer Service bulletin No 89, released in May 1963, described corrosion as the “greatest maintenance problem” for watercraft. The bulletin stated that Mallards operating in a salt-water environment might suffer corrosion in the lower skin of the wings in the fuel tank areas. Symptoms to watch for included “chronic leakage of fuel, looseness of sealant in the tanks, and/or blisters, swelling, or visible corrosion in the skin in the tank areas”.

In 1966, on his 85th birthday, Pappy Chalk made his final flight and sold his airline to a friend. By then he had 17,000 hours. Chalk’s Flying Service operated four Gooses and three Mallards and was fully staffed with pilots, maintenance and sales personnel.

Around this same time, Frakes Aviation was founded, an aviation business focused on converting aircraft. They purchased the rights to the Grumman Mallard and began replacing the piston engines with Pratt & Whitney Canada PT6 turboprops and upgrading the cabin to hold 17 passengers. The result became known at the Turbo Mallard and the modifications almost doubled the aircraft’s range as well as making it much more fuel efficient. Chalk’s Flying Service immediately saw the potential and started having their fleet of Grumman Mallards, by then eight aircraft, converted to the Turbo Mallard one by one.

I cannot afford another diversion but it pains me not to mention that one of the Mallards was hijacked in 1972, when two men forced their way on board, wounding the pilot, a mechanic and a bystander, and flew to Cuba. The men were never caught and it’s said that from then on, no Chalk’s aircraft was ever fuelled sufficiently to reach Cuba.

Also, I want to mention that Pappy Chalk continued coming into the office every day until he retired in 1975, during which time the airline was sold again, this time to Resorts International. Employees at the time said he would come with food for the birds and food for the staff and regale customers with stories of how the airline got started. He died in 1977 and I wondered if he’d been ill when he retired. But no, it turns out that he fell out of a tree in front of his house while he was pruning it.

The airline changed hands many times and was, at one point, owned by Donald Trump, who reduced the amphibious fleet to four or five Mallards (of which all but one were Turbos). At the same time, Chalk’s had become a symbol of Miami Beach. The television show Miami Vice featured a Chalk’s seaplane in its opening credit. Chalks seaplanes also appear in the music video for George Michael’s Careless Whisper and in one of the final scenes of Silence of the Lambs.

The next owner, Merv Griffin, attempted to get rid of the seaplanes all together and only offer flights directly to his resort in the Bahamas using the local runway but, apparently, the Bahamian government refused. Merv Griffin sold it in 1991, by which time most of Chalk’s destinations could be reached by land-based planes.

By 1999, the airline had gone through a series of owners and operators and the name was changed to Chalk’s Ocean Airways. By now, the Mallards were around 50 years old and Chalk’s Airline was the primary operator. Eighty years after Pappy Chalk founded the airline, a pilot told Air & Space magazine why she loved working there.

“It’s the closest thing you can get commercially to World War II flying—much more strenuous than most pilot jobs because of the change of the tides and the wind and the boats and the jet skis. It’s hands-on, no autopilot, with hop-skip-and-jump, 20-minute turns, and all-day-long days. But then they give you a lot of days off. It’s a wonderful job.”

Chalk’s Ocean Airways was proud of the fact that they were the longest continuously running airline and also that they’d operated all this time without a single passenger fatality. However, there had been an accident in 1994, when one of the Turbo Mallard’s crashed on take off, killing both pilots.

The NTSB report is somewhat confusing. The Turbo Mallard (officially a Grumman G-73-T) arrived at Key West Harbor in Florida with 13 passengers on board. After the passengers were disembarked, the flight crew planned to fly to Key West Airport for refuelling. Shortly after lift-off, something went terribly wrong.

From the report:

Witnesses stated they observed the seaplane take off from the water in the harbor area, and as the airplane climbed to about 100 feet the airplane pitched up, rolled left and crashed nose down in a left roll. The seaplane came to rest on the bottom of the harbor in about 30 feet of water.

The aircraft wreckage was examined where it fell, in about 30 feet of water in the harbour. The hull had been crushed and both wings damaged, with the propellers showing signs of curling and twisting. The flight controls and the aerodynamic surfaces showed fractures and failures consistent with overload. The bilge pump switch was in the off position, i.e. not pumping water out of the bilge.

The Mallard didn’t have a flight data recorder but it did have a cockpit voice recorder. The checklists for start, run-up and take off were only partially completed and, most importantly, the call out for bilge pumps was not recorded as a part of the before-take off checklists. As the aircraft lifted off, the first officer, who was pilot flying, complained about the nose pitching up and the captain stated that they might have a lot of water in the tail. The two pilots struggled to regain control of the aircraft until the sound of the impact with the water. The pilots’ cause of death was determined as salt water drowning.

Probable Cause and Findings

The National Transporation Safety Board determines the probable cause(s) of this accident to be:
Failure of the pilot-in-command to assure the bilges were adequately pumped free of water (adequately preflighted), which resulted in the aft center of gravity limit to be exceeded, and failure of the aircrew to follow the checklist. A factor related to the accident was the water leak.

I’m sure you are all, like me, wondering what water leak. However, there’s no mention of a water leak in the report other than in the findings (“F: Fluid, water – leak”) and the docket is not available online. I’m so bugged by this, I’ve emailed the NTSB to ask if they can shed any light on the subject although I am not really expecting a response.

The airline shut down in 2007. However, I’ve already gone on long enough; that will have to wait for another day.

Edit: The next post is now here.