The History of the Aleutian Goose – Part 1

The History of the Aleutian Goose – Part 1

The Aleutian Goose (N780) on Karluk Lake in Alaska soon after its major conversion. (From the Bill Bailey Collection.)

By David H. Marion – The Grumman “Goose” has been a legendary aircraft almost from its inception. The first examples of the G-21 series were originally designed, built, and certified in 1937. The G-21 series was initially intended to be used as VIP transports for a small group of wealthy businessmen who lived on Long Island and wanted to be able to commute to and from lower Manhattan. The group went so far as to create an informal consortium to back Grumman financially in developing what was for the company at the time a ground- breaking new aircraft. Prior to the Goose, Grumman had not yet built another aircraft anything at all like it – a twin-engine, essentially all-metal, monoplane. In that regard, it was a radical departure into new territory for the still somewhat fledgling aircraft manufacturing company.

The Grumman Goose has gone on to take a place in aviation history not unlike other significant types developed during the same time period; types such as the Douglas DC-3 and the Beech 18. Examples of each of them are still flying, doing their jobs and making money for their owners to this day. The Goose, probably mostly due to its especially heavy-duty construction as a flying boat, which was necessary to withstand the rigors of open-ocean landings and operations, also developed a reputation as an unusually tough and durable airframe. Consequently, it was often used as the basis of or test-bed for some very creative and diversified conversions and modifications.

That list of experimental test-beds and conversions includes the Kaman K-16B tilt-rotor proof-of-concept vehicle that was a “grandfather” to the modern Bell-Boeing MV-22 “Osprey” currently operated by the US Marine Corps. The list also includes several series of seaplane hydrofoils which the US Navy, in conjunction with contractors such as Edo Aircraft Corporation, used for experiments in the 1950’s and 1960’s to explore alternative means of enhancing seaplane performance. It also includes all of the McKinnon conversions that were eventually re-certified as completely new aircraft under a separate FAA-approved type certificate, no. 4A24. It includes as well the so-called “Aleutian Goose” that was designed and built between 1969 and 1975 as a custom wildlife patrol and survey aircraft by and for the Fish & Wildlife Service, an agency within the U. S. Department of the Interior in Alaska.

Aleutian Goose

Grumman Goose Legacy of Research and Development

Problematic Issues

Alaskan aviation legend Terry Smith was especially proud of the Aleutian Goose. As a young pilot, he flew it for the eFish & Wildlife Service (FWS) and later for the Office of Aircraft Services (OAS) which succeeded it in providing and operating aircraft on behalf of several federal agencies in Alaska under the jurisdiction of the U. S. Department of the Interior. Many years later, after the Aleutian Goose was eventually declared surplus by the government and sold first to another private owner in the interim, Terry Smith co-owned that same unique, turbine-powered Goose in partnership with financier and businessman Jim Wikert of Dallas, TX via a corporate entity called Aircorp III Inc. But more than anything else, Theron A. “Terry” Smith, Jr. was especially proud of the Aleutian Goose because it was his dad, Theron A. Smith, Sr. who both designed and built the thing for FWS in the first place.

Since the Aleutian Goose was actually designed and built by Theron A. Smith, Sr. and his team for and on behalf of the federal Fish & Wildlife Service at their hangar in Anchorage, and in fact it was neither designed by nor built by McKinnon Enterprises, then how could it have ever been formally identified or officially registered as a supposed “McKinnon G-21G”? The fact of the matter of course is that it really was not a “McKinnon G-21G”, never conformed to the McKinnon G-21G type design as defined by its FAA-approved Master Drawing List no. MPD-90995, was never properly certified as such by McKinnon or by anyone else, and never should have been so identified by FWS or registered as such by the FAA.

The invalid formal identification of the Aleutian Goose came about because that is exactly what FWS told the FAA, but the FAA never bothered to corroborate the FWS claim or require any formal documentation to support it. In fact, the very first time that FWS notified the FAA that the aircraft in question supposedly had been so converted, it was via nothing more formal or official than a handwritten note sent to the FAA Aircraft Registration Branch in Oklahoma City by Theron Smith’s colleague, Jarrett L. “Jerry” Lawhorn, in March 1974. Aside from the handwritten note, there was no formal paperwork of any kind to substantiate its change of identification and the aircraft in question was never properly certified as a “McKinnon G-21G” by McKinnon Enterprises Inc., the FAA, or anyone else.

All of the Goose conversions “built” and properly certified under TC no. 4A24 actually by McKinnon Enterprises Inc. were documented using standard FAA Forms no. 317Statement of Conformity” reflecting their production under the authority of 14 CFR Part 21, Subpart FProduction under Type Certificate.” No such forms were ever filed with the FAA in regard to the conversion of the Aleutian Goose and it was instead treated as if a new model aircraft could be produced under Part 43 simply by means of major alterations documented with FAA Forms 337.

Similarly, each of the actual McKinnon Goose conversions was given a new data tag by McKinnon and it was always mounted per the requirements of 14 CFR Part 45 on the exterior of the aft fuselage under the leading edge of the left horizontal stabilizer. Historical photographic analysis of the Aleutian Goose shows that no such data tag was ever mounted in that location on it. Furthermore, it also fails to show any evidence of any kind of valid data tag ever having been mounted anywhere else on the aircraft after its conversion by FWS.

A Special Mission

The so-called “Aleutian Goose” project was always Theron Smith’s “baby” and on the basis of all available official records pertaining to the subject, it is evident that McKinnon had very little if anything ever to do with it. The Fish & Wildlife Service wanted a better wildlife “survey” and patrol aircraft and their chief aircraft maintenance supervisor, Theron Smith, set about figuring out how they might modify for themselves a spare Grumman G-21A Goose, an otherwise legendary seaplane in its own right, to achieve that specific goal. The most important design considerations for FWS were turbine engines for power and reliability and an enlarged cockpit in order to allow them to add two extra “observer” seats forward of the wing in order to take advantage of the visibility from that position.

One of the most important and unique features of the FWS design of the Aleutian Goose was the use of Garrett AiResearch (now Honeywell) TPE331 series turbine engines. According to transcripts of interviews with Jerry Lawhorn conducted in 1999, long after his retirement from FWS, the TPE331 engines were chosen in place of the PT6A engines already being used on other Gooses by McKinnon and by Alaska Coastal-Ellis Airlines because of a perception on the part of FWS that it was more difficult to crack the cases of the gear reduction cases of the TPE331 engines during abrupt or high-G maneuvering. It was similarly perceived that the TPE331 engines had more instantaneous throttle or power response, which they believed provided a greater margin of safety while operating in open ocean swells, and better fuel economy because of their fixed-shaft turbines.

Aleutian Goose

The Aleutian Goose (N780) in fresh paint soon after completion of its conversion (Picture from Bill Bailey Collection)

Apparently too, according to testimony by Jerry Lawhorn, he and Theron Smith traveled to eastern Canada to talk to the engineers at Pratt & Whitney, who it turned out were reticent about working with the FWS people to develop an inverted mounting configuration for their PT6A engines. FWS wanted an inverted installation in order to allow the engine air intakes to be on top of the nacelles instead of on the bottom in order to be further away from water spray and reduce the potential for harmful water ingestion by the engine. (To me this claim is strange because the PT6A series does not have to be mounted “inverted” in order to have its air intake on top of the nacelle; the PT6A’s actual air intake is annular and encompasses the full circumference of the aft body of the engine – so it doesn’t care from which direction the air is ducted.) Lawhorn also related how they encountered some bias to putting something other than Pratt & Whitney engines on a “Grumman” aircraft as traditionally had always been the case.

Undeterred, the Fish & Wildlife Service eventually made a deal with Garrett AiResearch for three 715 shp TPE331-2UA-203D series engines to be custom-built especially for FWS for use on the Aleutian Goose and also on a DHC-2 Beaver (N754) which was similarly modified for FWS by Volpar Inc. The custom-built engines were configured to be mounted inverted from the nominal TPE331 series installation as denoted by the “U” in the model number indicating “upside-down.”

The custom-built engines also had more corrosion resistant aluminum cases instead of the more common, lighter-weight but also more reactive (i.e. prone to corrosion) magnesium cases. These were specified because of the need for FWS to operate in more highly corrosive salt water environments; this feature was denoted by the “A” in the engine model number. They were all setup with a common, “quick engine change” (QEC) prop, engine, accessories, and mount configuration to allow complete interchangeability between either side of the Goose and the Beaver. FWS initially planned to convert three Gooses and all nine of their DHC-2 Beavers to the new, common TPE331 turbine engine configuration.

Additionally, it was determined that the top-mounted air intakes specified by FWS improved the sight lines from the cockpit in terms of the airplane’s survey and patrol mission and the TPE331 engines were also perceived to have better inherent ice ingestion prevention design characteristics based on how close the compressor blades were mounted to each other inside the engines and on the speed at which the engine rotated – something like 43,000 rpm. It was assumed that at such speeds, the compressor section would present an effectively solid and essentially impenetrable “disc” to any ice that may have been ingested by the engine.

The Project Aircraft

The specific aircraft that was chosen to be the prototype of the FWS Aleutian Goose conversion project was N780, one of several war-surplus, ex-US Navy model JRF-5 Gooses that the agency had obtained many years earlier. The particular Goose that was chosen was originally manufactured by Grumman in July 1944 as serial number B-72. It was subsequently accepted by and delivered to the US Navy on July 26, 1944 and entered service as Bureau of Aeronautics serial (Bu.) no. 37819.

The US Navy service of JRF-5 Bu. no. 37819 was unremarkable. It was first formally assigned to NAS Whidbey Island, Washington in August 1944. It was transferred to NAS Alameda, California in August 1946 for re-conditioning and then re-assigned to Pool BAR (think “motor pool” Bureau of Aeronautics Representative) at the Grumman factory in Bethpage, Long Island, NY in June 1947. From there it was re-assigned to NAS Quonset Point, Rhode Island in January 1948 and it remained there at least until September 30, 1948.

Some of its subsequent Navy records went missing but it was still at NAS Quonset Point on July 28, 1949 when its tailwheel collapsed during a landing. After being repaired, it went back to Pool BAR Bethpage in January 1950 for another overhaul before being assigned to the 13th Naval District at NAS Whidbey Island in Washington once again on April 12, 1950. It then went all the way back across the country once more, to NAF Annapolis, Maryland on August 12, 1950 and from there back again to NAS Quonset Point, Rhode Island on December 27, 1951 for yet another overhaul. It was made available for disposal on August 12, 1952 and “Struck Off Charge” (SOC) on October 13, 1952 with a listed total of only 1,420 hours Time in Service.

ex-USN JRF-5 Bu. 37819 stored at Lake Hood, AK 1962

After being declared surplus by the Navy, Goose serial no. B-72 was transferred to the Fish & Wildlife Service of the U. S. Department of the Interior in Alaska and registered as N780 on November 13, 1952. Unlike other Goose aircraft in its inventory however, FWS did not immediately put N780 into service and instead it was held in reserve and essentially stored, albeit outside in the open, for about 15 years. By the late 1960’s, it was probably one of the lowest time Gooses still in existence.

The Conversion Program

Drafting of plans and blueprints to accomplish the necessary modifications for their new “Aleutian Goose” wildlife survey and patrol aircraft began in earnest probably sometime during 1968 or even a bit earlier. The records that are still available show that by January 1970, Goose N780 was already well under way to being fully converted by the FWS team in Anchorage. A lot of evidence comes from documentation written by Gary L. Killion, a DER and FAA propulsion systems engineer who worked out of the Los Angeles aircraft certification office. He was tasked with oversight of both the FWS and McKinnon’s own turbine Goose conversion projects that were ongoing during the late 1960’s and early 1970’s.

According to the FAA Conference Report dated January 6-9, 1970 that was written by Mr. Killion, the Aleutian Goose conversion project was originally assigned FAA project no. A3133WE-DS as it was originally conceived by FWS working in consultation with McKinnon. Their plan was to convert a legacy Grumman model G-21A into a McKinnon model G-21C under Section I of TC 4A24 simultaneously with incorporation of a new STC to be developed and approved to cover the installation of the TPE331 turbine engines. The new STC would be used in place of McKinnon’s STC no. SA1320WE which had already been approved by the FAA and allowed the use of PT6A series engines on McKinnon G-21C and G-21D aircraft already otherwise converted and re-certified under TC 4A24.

To that end, on January 28, 1969 McKinnon applied for a new STC to install TPE331 engines on Grumman G-21A aircraft and the FAA convened a new Preliminary Type Certification Board for the project on February 6, 1969. Ironically, the engine installations were to be done in accordance with the details and drawings for the TPE331 engine conversion previously developed by Volpar Inc. and approved by the FAA for “tri-gear” Twin Beech models 18, a separate conversion developed by Volpar which was later adopted for use by Beech on their own new production aircraft.

The Volpar drawings for the TPE331 engine installation were subsequently incorporated directly into a new Master Drawing List (MDL) approved for the project in the form of report no. MPD-BWL-0001, which was completely separate and distinct from the official MDL for the McKinnon model G-21G under TC no. 4A24. The subsequent conference report dated February 10, 1969 apparently noted (as later reiterated in Mr. Killion’s conference report of Jan. 6-9, 1970) that the actual conversion work on N780 was already progressing at the FWS maintenance hangar on Lake Hood in Anchorage. It was also actually and quite problematically outpacing production of the formal drawings and blueprints which were necessary to perform the requisite FAA conformity inspections along the way.

The Aleutian Goose (N780) along side Beaver N754 undergoing conversion in FWS hangar in Anchorage

However, the FAA eventually determined, and informed both FWS and McKinnon accordingly, that the idea of simultaneously converting a legacy Grumman G-21A (originally certified under TC no. 654) into a new McKinnon model G-21C under TC 4A24 Section I also with turbine engines per STC no. SA1320WE, just as McKinnon had already done with two previous aircraft, or even per a new STC for the TPE331 engines based directly on the Volpar STC already approved for the Beech 18 series, was still not valid per the applicable regulations. They suggested instead that the engineering data already approved under STC SA1320WE should first be incorporated into TC 4A24 to create several completely new turbine Goose models as applicable.

New Models Certified – and Not

In response to that suggestion, on April 25, 1969, McKinnon made a formal application to the FAA to add the new models G-21E, G-21F, and G-21G to his type certificate no. 4A24. The model G-21E was to be the first integrated certification of the various conversions previously done by McKinnon as so-called Grumman G-21A and McKinnon G-21C “Hybrid” turboprops, per STCs SA1589WE and SA1320WE respectively, all of which were re-certified up to only 10,500 lbs.

The model G-21F in particular was envisioned to have all of the special mission features specifically planned by FWS for their custom wildlife survey and patrol aircraft. In addition to the major features already noted, it included a unique windshield that utilized parts from a French bus and which was never used on any other Goose, as well as a completely new cockpit flight control system utilizing floor-mounted yokes salvaged from an Aero Commander in order to free up space on the instrument panel. The routing of the control cables to the empennage (rudder, elevators, & trim) was changed to go through a completely new dorsal fairing along the top of the fuselage in order to install a unique extra fuel tank in the lower hull just behind the main landing gear.

In conjunction with other fuel tank modifications developed by McKinnon for his own G-21 series aircraft, which raised the original fuel capacity of the Goose from 220 US gallons to a maximum of 586 US gallons, the lower hull or “belly” tank and associated plumbing in the G-21F increased its total fuel capacity to an unequalled 708 US gallons. The G-21F was also planned to be reinforced as necessary to operate all the way up to 12,500 lbs. The re-routing of the control cables was done to permit the cabin floor and entire lower hull to be sealed and used as supplementary buoyancy chambers. At the time of the formal application by McKinnon for the new model G-21F, the FWS conversion of the so-called “Aleutian Goose” was accordingly re-designated as FAA project code no. CA3133WE-D.

“Real” McKinnon G-21G serial no. 1226 – N70AL

Finally, the design of the McKinnon model G-21G for the first time incorporated all of the structural reinforcements originally included by McKinnon in his earlier models G-21C and G-21D conversions to permit operation at the “small” aircraft and single-pilot, maximum gross take-off weight limit of 12,500 lbs along with more powerful 680 shp PT6A-27 turbine engines. It is not coincidental that the two 680 shp turbine engines that were specified also exactly equaled the total horsepower (1,360) of the four 340 hp Lycoming GSO-480-B2D6 geared, supercharged, piston engines that were previously approved and actually installed on the earlier McKinnon models G-21C and G-21D.

Just as with all of his previous conversions as well, McKinnon’s model G-21G included larger cabin windows, retractable wingtip floats, a “radar” nose, a one-piece “wrap-around” windshield, and numerous other detail changes including full structural reinforcement of the cockpit walls, main hull bulkhead at Hull Sta. 13, the main landing gear aft drag braces, and the hinges and framing for the wing flaps.

During the summer of 1969, on the basis of existing engineering data already compiled by Strato Engineering Inc. for the previous McKinnon Goose conversion projects, the new model G-21E was approved by the FAA under Section III of TC 4A24 on July 17, 1969 and the new model G-21G was approved under Section IV of the TC on August 29th of that same year. During that same time too McKinnon proceeded with the conversion of what would become his very first actual new model G-21G. Registered at the time as N5558, this former USN model JRF-5, Bu. no. 37809 (aka Grumman G-21A serial no. B-62) was converted and re-certified as McKinnon G-21G serial no. 1205 on September 5, 1969.

Scaling Back

Very shortly after being re-conceived as a new McKinnon model G-21F to be certified under TC 4A24, the “Aleutian Goose” project was almost de-railed once again. For budgetary reasons, FWS decided to scale back its initial plans to build three such new aircraft and to build only one new model G-21F “Aleutian Goose” instead. Through Strato Engineering Inc. FWS petitioned the FAA on November 3, 1969 to allow them both to simplify and reduce the scope of drawings that they were being required to produce in conjunction with the actual modifications to the single aircraft in question, N780. In their response dated December 12, 1969, the primary West Coast FAA engineering office in Los Angeles (FS-110) determined that the scope of a project to certify a completely new model under Part 23 and TC 4A24 would require full documentation, engineering drawings, and structural analyses beyond the scope of involvement anticipated by FWS in Anchorage regardless of how many aircraft of the new type they planned to build.

On the subject of the progress made on the Aleutian Goose conversion project, Mr. Killion’s Conference Report from January 1970 also discussed how far along the conversion work had gone. “From a cursory inspection of the prototype, it was noted that the fuselage structural changes were completed and the wing fuel modifications were completed. The engine nacelles were in place; however, the [TPE331] engines had not been installed. None of the control system, instrument panel or cabin interior changes had been incorporated. The hull fuel tank was completed but not installed.” In other words, actual work on the conversion project was obviously still continuing essentially unabated and almost without regard to the status of the engineering data, blueprints, certification plans, or other formal paperwork.

In order to satisfy the FWS request to simplify the required documentation, the FAA informed FWS that it would not be possible to certify the aircraft in question as a new model G-21F. The FAA suggested instead that the new airplane could be re-certified along a different route by first being converted and re-certified as a new McKinnon model G-21G, the design of which recently had been approved separately, and thereafter be modified by means of a new “one time only” STC to account for the numerous detail differences between the approved new type design for the model G-21G and the so-called model “G-21F” configuration anticipated and desired by FWS. As a result of this change in plans, it seems that the FAA project number once more reverted to the original designation of A3133WE-DS.

As also noted in Mr. Killion’s conference report of January 6-9, 1970, FWS eventually asked to separate out certain aspects of the numerous modifications that they had in mind to alter the aircraft from the standard G-21G type design to their intended model “G-21F” final configuration. They wanted to pursue certification of the simpler aspects of the project, such as a new hydraulic system to be used to power the landing gear and wing flaps, “locally” in Alaska through their contacts there at the FAA aircraft engineering office in Anchorage. The hydraulic system eventually became FAA project no. A590AL-S, which was formally submitted on May 26, 1971, and then eventually was approved in the form of STC no. SA514AL, which was subsequently officially owned by the USDI’s Office of Aircraft Services.

McKinnon’s Problems

Quite separately from the FWS Aleutian Goose project taking place in Anchorage, AK, things were going in a completely different direction for Angus McKinnon and his company McKinnon Enterprises Inc. based in Sandy, Oregon, just east of Portland near Mt. Hood. After completing his first real model G-21G conversion (N5558, serial no. 1205) in September 1969 and then a second and final model G-21G (N70AL, serial no. 1226) in March 1970, McKinnon completed his last actual Goose conversion of any kind in May 1970. Registered as N121H, it was converted from G-21A serial no. 1013, actually the very first official model G-21A ever built by Grumman, into McKinnon G-21E serial no. 1211. N121H had been owned by Halliburton Oil Well Cementing Co. since 1954 and as the Halliburton Corporation they continued to operate it after its conversion all the way up until 1991 – a total of 37 years with the same company.

However, after completing his conversion of N121H as his one and only official model G-21E, McKinnon seems to have stopped making payments on several bank loans that he had gotten to finance his operations over those last few years. By the middle of 1971, the banks and other creditors had foreclosed on their loans. The bankruptcy court in Portland eventually ruled against him and issued its final decree on December 28, 1971, at which point all of McKinnon’s physical assets that had been used for collateral on the loans (including N5558, his G-21G Turbo Goose serial no. 1205 which he had up till then kept for himself) were seized. All of those assets were auctioned off by the Sheriff of Clackamas County, Oregon on January 3, 1972 and by that date, McKinnon Enterprises Inc. was effectively out of the airplane conversion business.

The Aleutian Goose project on the other hand, not being in McKinnon’s hands at all, continued unabated in the FWS hangar in Anchorage. In Part 2, we’ll explore more details of its actual conversion, the subsequent flight test program, and its eventual re-certification as a supposedly highly modified McKinnon G-21G – all without ever being converted or certified as a basic McKinnon G-21G in the first place.

Dave Marion is the Technical Content Editor at Seaplanemagazine.com. As A&P and IA with 29 years of experience in aircraft maintenance, he is also a Commercial Pilot with Airplane, Single & Multi-Engine, and Instrument ratings. He has a BA from Colgate University in 1984 and also graduated cum laude from Embry-Riddle Aeronautical University (DAB) with a BS in Aviation Technology in 1990. He can be reached along with all of the editors via E-Mail: editor@seaplanemagazine.com

Next Up: Find out more about Seaplanemagazine.com and our team

Share This!