Goose owners seem to do the wackiest things

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Goose owners seem to do the wackiest things

Postby Rajay » Sun Jun 30, 2013 11:01 pm

Call it “Antilles Seaplanes Service Bulletin No. 1” if you will:

To: all current owners or operators of Grumman G-21A Goose aircraft certified under ATC-654 as well as other “McKinnon” type G-21 aircraft converted and re-certified under TC 4A24.

Re: “McKinnon” Supplemental Type Certificates (STC) for G-21 series aircraft

For the record, Atlantic Coast Seaplanes LLC (d/b/a Antilles Seaplanes LLC) currently owns and holds all of the rights to all of the former “McKinnon” Supplemental Type Certificates (STC) that apply to the Grumman G-21 series of “Goose” aircraft originally certified under ATC-654. In addition, there are a couple of other “McKinnon” STCs that Antilles now owns that actually do not apply to legacy Grumman G-21 series (G-21, G-21A, and ex-military OA-9 and JRF-1 through JRF-6B) aircraft and instead actually apply only to “McKinnon” models G-21C and/or G-21D as converted and re-certified under TC 4A24.

The “McKinnon” STCs now owned by Antilles Seaplanes, and which were previously owned in the interim first by Viking Air Ltd of Sidney, BC, Canada and then by Aero Planes LLC of Hillsboro, OR, USA, include the following:

Applicable to / eligible for installation only on Grumman G-21 or G-21A aircraft still certified under ATC-654;

SA4-677 Installation of main cabin picture windows (type 1 ref. dwg. MPD-5001)

SA4-678 Installation of extended, fiberglass “radar” nose cone

SA4-680 Installation of 1-piece “wrap-around” windshield

SA4-681 Installation of extended dorsal fin

SA4-682 Installation of retractable wingtip floats

SA4-683 Installation of 60 US Gallon auxiliary fuel tanks in outboard wing spar boxes

SA4-1055 Installation of rotary beacon

SA4-1109 Installation of metalized wing skins in place of original fabric covering aft of rear spar on outboard wing panels

SA4-1467 Installation of STC SA4-682 retractable wing floats (incorporated by reference) and other changes to increase maximum gross take-off weight to 9,200 lbs.

SA4-1550 Installation of wing leading edge landing lights

SA4-1551 Installation of electric motor landing gear retraction system

SA59WE Installation of Chandler-Evans electric fuel boost pumps (one-time only for N525, G-21A s/n B-117, *currently registered in Canada as C-GYVG)

SA101WE Installation of main cabin picture windows (type 2 ref. dwg. MPD-5100)

SA108WE Modification of aft cabin bulkhead Sta. 26, bulkhead Sta. 33, cabin floor from Sta. 13 to 29, & addition of buoyancy tanks

SA355WE Installation “tunnel-type” hull vents

SA1589WE Installation of 550 shp PT6A-20 turbine engines in Alvarez-Calderon “clean-wing” nacelles on Grumman models G-21 or G-21A certified under ATC-654. Note as well that by means of this STC, the maximum gross take-off weight of aircraft so modified was increased all the way up to 10,500 lbs.

SA1969WE Installation of passenger seats

SA2317WE Installation of co-pilot’s brakes

Applicable to / eligible for installation only on McKinnon G-21C or G-21D aircraft that have been converted and re-certified under TC 4A24;

SA1320WE Installation of 550 shp PT6A-20 turbine engines in Alvarez-Calderon “clean-wing” nacelles on McKinnon models G-21C or G-21D re-certified under TC 4A24; installation of Alvarez-Calderon electric flaps on model G-21D only.

SA1751WE Increase Main Fuel Tank Capacity to 336 gal. (applicable only to McKinnon G-21C aircraft when installed in conjunction with STC SA1320WE)

The “wacky” part comes from the fact(s) that somewhat recently, I learned that several of these STCs have been completely misused on aircraft for which they were never approved or certified – in some cases apparently with the “full knowledge” and permission or authorization of a previous owner of the STCs in question.

I use the term “full knowledge” only very loosely because apparently they had no real clue how the STCs in question were certified or approved for use on certain aircraft. They also apparently had no clue as to the actual scope of the modifications or alterations approved under the STCs in question.

Either that or Goose owners, by virtue of that fact alone, are just so darn "cool" that the rules just don't apply to them - or so they seem to think!
Last edited by Rajay on Mon Jul 01, 2013 4:28 am, edited 2 times in total.
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Re: Goose owners seem to do the wackiest things

Postby Rajay » Sun Jun 30, 2013 11:06 pm

Case 1: Not-so-long-ago a Grumman G-21A Goose was widely advertised for sale and in the ads posted on various Web sites online, the previous owner / seller claimed that it was equipped with a “Viking” heavy-duty tailwheel trunnion and caster assembly, part no. MPD-7000-1.

AFAIK (and I “know” better than almost anyone else) that MPD-7000-1 tailwheel assy. is actually a McKinnon design / part that has never been approved for use on a Grumman G-21A that is still certified under ATC-654*, so I took it upon myself to contact the seller and ask them about it.

They sent me copies of a logbook entry and Form 337 which claimed that the heavy-duty tailwheel trunnion and caster assembly had been installed while still owned by a previous owner supposedly in accordance with a “partial installation of STC SA1320WE.”

The “thing” is that STC (SA1320WE) has never been approved for use on a Grumman G-21A still certified under ATC-654, and, maybe worse, it has absolutely nothing to do with a tailwheel! So, just go figure!

I also have a problem with the concept of a “partial installation” of an STC. I’ve heard arguments that “approved data” are approved data, no matter how they are used, but I don’t think that’s valid. There is such a thing as context and I don’t believe that you can take the explicit approvals for these STCs completely out of context. You either install a modification actually “in accordance” with the STC – or not. And actually on the aircraft type for which the STC is specifically approved – or not.

STC SA1320WE, as noted earlier, nominally covers only the installation of a pair of 550 shp PT6A-20 turbine engines on a McKinnon G-21C or G-21D aircraft (converted and re-certified under TC 4A24) in place of their “original” (post-McKinnon conversion that is) four 340 hp Lycoming GSO-480-B2D6 geared, supercharged, “flat” piston engines – and “related” changes.

There is nothing about the heavy-duty tailwheel assembly that is in any way “related” to that turbine engine swap. In fact, according to the Master Drawing Lists (MDL) that officially define each model, the MPD-7000 tailwheel assy. is a mandatory design feature required for “conformity” as a McKinnon G-21C or G-21D (and for that matter also the later model G-21G as well – i.e. all of the McKinnon conversions that were re-certified up to 12,500 lbs or thereabouts) prior to and completely separate from any discussion of the turbine engine conversion.

Any claim that this installation was approved solely on the basis of STC SA1320WE is completely false, wrong and invalid – that STC does not apply in any way, shape, or form – either to Grumman G-21A aircraft or to tailwheels of any kind.

The installation of the MPD-7000 series tailwheel assy. could be (or have been) done via a “field approval” in its own right, because related engineering data do exist, but it still would not be explicitly through or because of anything to do with STC SA1320WE.

So, of course now I have to wonder on just how many other Grumman G-21A aircraft that are still operational this “improper” and actually unapproved installation was done. I tried to contact the former STC owner’s Customer Service dept. but they told me that they no longer have any records pertaining to the STC in question. I have to imagine that even if they did, they wouldn’t admit to it at this point.

* “had never been approved for use on a Grumman G-21A that was still certified under ATC-654” that is until just last year when I worked with the Quality dept. at Pacific Coastal Airlines to help them get a new limited STC from Transport Canada for use of the McKinnon heavy-duty MPD-7000 series tailwheel components on their fleet of legacy Grumman G-21A aircraft. They made that effort to get the new STC because spares for the old OEM Grumman parts are no longer available. Even if they were, they were designed for use with old-style balloon type tires and are not compatible with modern tire profiles.
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Re: Goose owners seem to do the wackiest things

Postby Rajay » Sun Jun 30, 2013 11:08 pm

Case 2: A while back, I was consulting with an A&P/IA mechanic who maintains a different Grumman G-21A Goose and he was having to scrounge and/or fabricate parts to repair the tailwheel retraction system which had broken and caused the tailwheel to collapse on the ground.

He mentioned just in passing that “his” Goose was equipped with the McKinnon “long-range” (i.e. auxiliary) fuel tanks. I asked knowingly “oh you mean the 60 gallon ‘slipper’ tanks in each of the outboard wing spar box sections?” He said “no, the extra 116 gallon ‘wet-wing’ in the center section.”

Red flags and alarm bells!

I told him “that STC was never approved for use on a Grumman G-21A.”

STC SA1751WE, which extends each of the original Grumman OEM 110 gallon “wet-wing” sealed spar box section fuel tanks in the inboard wing stub into the previously “dry” wing center section carry-through structure over the main cabin, increasing their respective capacities to 168 gallons each and the total combined capacity from 220 gallons to 336 gallons, is specifically approved for use only on “McKinnon G-21C” aircraft that have been converted and re-certified under TC 4A24 and that have also been modified with a pair of 550 shp PT6A-20 turbines in accordance with STC SA1320WE.

IIRC he said that he had paperwork “approving” the installation, but it wasn’t in the copies of its “Airworthiness” records that I obtained from the FAA archives in Oklahoma City. The installation must have been done while the aircraft in question was previously owned and registered in Canada. I have found that unlike the FAA, Transport Canada does not hang on to any old records for aircraft that are de-registered there, either because they were scrapped or sold to a new owner in a different county. In fact, very soon after an aircraft is de-registered, all of their old records for that aircraft are purged. So, other than whatever records the current owner actually has in his possession, there is no official record of this modification.

Once again, unless it was actually accomplished in accordance with a “field approval” (or its Canadian equivalent) that was only loosely based on the similarities between the Grumman G-21A and the McKinnon G-21C, STC SA1751WE was not in any way directly applicable to or authorized for installation on a Grumman G-21A aircraft still certified under ATC-654.

Once again as well, I was left wondering on just how many other Grumman G-21A aircraft a former owner of this STC improperly “authorized” its installation.
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Re: Goose owners seem to do the wackiest things

Postby Rajay » Sun Jun 30, 2013 11:12 pm

Case 3: Shortly – as in just a few months - after its current owner (falsely IMPO – but that’s another story) started claiming that his Grumman G-21A turbine conversion (which was actually re-certified originally under ATC-654 as modified by STC SA1589WE according to legacy records from the FAA archives in OK City) had been supposedly “rebuilt” or “upgraded” in order to be re-certified as a so-called “McKinnon” model G-21G under STC SA1320WE* he had his mechanic also install on it the “McKinnon” co-pilot’s brakes modification per or in accordance with STC SA2317WE. At least that’s the supposed basis on which they filed the requisite FAA Form 337.

Apparently, he thought that he “could have his cake and eat it too” as the old saying goes. According to that owner, his aircraft was no longer a “Grumman G-21A” certified under ATC-654 but he thought nonetheless that he could install on it an STC that was officially applicable to and authorized for installation only on “Grumman G-21A” aircraft still certified under ATC-654.

In all fairness, McKinnon’s original application to the FAA for a new STC for the installation of a second set of brake pedals and master cylinders on the co-pilot’s side of the cockpit requested that it be applicable to all G-21 series aircraft, both Grumman G-21 and G-21A aircraft still certified under ATC-654 and to McKinnon G-21C, G-21D, G-21E, and G-21G aircraft that had been converted and re-certified under TC 4A24. However, when the FAA actually approved and formally issued STC SA2317WE in February 1971, as it was officially written, it applied only to Grumman G-21 and G-21A aircraft still certified under ATC-654.

Generally speaking, the FAA does not like to issue STCs applicable to a particular type design or model of aircraft to the current owner of the TC under which that type design or model was originally certified. The expectation is that the TC owner should instead just amend his own TC to cover the changes he is requesting.

Whereas McKinnon obtained DER (i.e. FAA qualified “engineering”) approval for the installation of co-pilot’s brakes on all G-21 series aircraft, Grumman and McKinnon alike, in support of his application for the new STC, the FAA’s expectation was or would have been that he simply revise the Master Drawing Lists for each of the models already covered under his own TC 4A24. By that means, the co-pilot’s brakes would have become an approved “factory” option on those aircraft and could be installed or removed as an only “minor” alteration – and STC SA2317WE was necessary only to install those same co-pilot’s brakes on legacy Grumman G-21A Goose aircraft not covered by McKinnon’s TC 4A24.
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Re: Goose owners seem to do the wackiest things

Postby Rajay » Sun Jun 30, 2013 11:13 pm

*Note too, in regard to “another story” that as a corollary of 14 CFR § 45.13(a) a particular aircraft is “properly” identified, at least in an official sense - such as on its FAA Certificate of Airworthiness or Certificate of Registration - only in terms of who actually “built” it and not necessarily by who originally “designed” it or who may have owned the TC either originally or at the time that it was built. Because of that, this owner’s claim that his “Grumman G-21A” had become a “McKinnon G-21G” as a direct result of his own conversion efforts “in the field” were then and still now are not valid. It would have been a “McKinnon G-21G” if and only if Angus G. McKinnon or his company McKinnon Enterprises Inc. had both done the conversion themselves and had also officially re-certified it as such under TC 4A24.

Nobody other than McKinnon Enterprises Inc. can (as in has ever been allowed to) build or manufacture a “McKinnon” aircraft – not even subsequent owners of TC 4A24 and/or all of the former McKinnon STCs. If Viking Air Ltd had ever converted or “built” a new G-21G, it would have been a “Viking G-21G”, if Aero Planes LLC had ever converted or “built” a new G-21G, it would have been an “Aero Planes G-21G”, and if / when Atlantic Coast Seaplanes LLC (d/b/a Antilles Seaplanes LLC) ever builds a new G-21G, it will be an “Antilles G-21G”. The fact of the matter is that McKinnon only ever “built” two model G-21G aircraft and they were (and still are) serial nos. 1205, currently registered as N77AQ, and 1226, ever since its conversion registered only as N70AL. No other so-called model “G-21G” aircraft were ever “built” or certified as such actually by McKinnon.

In the case of this particular aircraft, McKinnon did not ever so much as claim to have converted or “built” it into a G-21G or any other model previously certified under TC 4A24. In fact, McKinnon Enterprises Inc. only “modified” or “altered” the aircraft in question, as previously indicated and still officially speaking, under the auspices of ATC-654 and STC SA1589WE. McKinnon also never “signed it off” under the authority of his Production Certificate (PC no. 409) but instead signed if off only as a repair and “alteration” performed by his repair station (CRS no. 4424.) From the time of its “modification” and official re-certification as a “Grumman G-21A Turboprop” in January 1968 and right up until the time of his death in November 1991, as far as Angus McKinnon himself was ever concerned, the aircraft in question remained a “Grumman G-21A” certified under ATC-654.

In contrast, the current owner did not buy it until 1996 – at which time the official Bill of Sale and FAA Certificates of Airworthiness and Registration all still officially identified it as a “Grumman G-21A” Turboprop. It actually wasn’t until 2001 that he started claiming to have “rebuilt” and/or “upgraded” it to a “McKinnon G-21G” configuration – but he still doesn’t seem to realize that that does NOT make it an actual “McKinnon” G-21G. As an amateur-built copy of a type certificated design, it should now be identified so far as its “make” or “manufacturer” is concerned in terms of the name of the TC Holder at the time it was converted or “built” hyphenated with his own name.

It also should have been identified at that point with a unique serial number that is supposed to be of even a different format than an original “factory” issued serial number so that it is not and in fact cannot be confused with an actual “factory” built aircraft. Instead however, the current owner chose a serial number that both uses the same format as a “factory” serial number and that was already previously issued to a completely different airframe. It is also one which was officially “retired” when that other aircraft was further modified and subsequently re-certified all over again as a different model with another completely different serial number of its own.

Finally, it should also be noted that because it was only “amateur-built” – i.e. without any kind of manufacturing certification or FAA approval under 14 CFR Part 21, the aircraft in question should not have been subsequently eligible for the Standard Certificate of Airworthiness that was issued to it and should instead now have only an Experimental CoA.

This one is going to take a virtual mountain of paperwork to “fix”.
Last edited by Rajay on Sat Jul 06, 2013 4:16 am, edited 2 times in total.
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Re: Goose owners seem to do the wackiest things

Postby Rajay » Sun Jun 30, 2013 11:19 pm

Additional Analysis:

IMHO one of the major problems with these “McKinnon” STCs – or at least various people’s “understanding” and use of them over the years, seems to be the impression that all of the different “McKinnon” Goose aircraft produced between 1958 and 1970 were converted as such simply by installing these STCs on legacy Grumman G-21A airframes. That is not true; far from it in fact.

Generally speaking, each of the “McKinnon” STCs applicable for use or installation on legacy Grumman G-21A aircraft still certified under ATC-654 was a stand-alone modification in its own right. The problem with any particular STC or other modification that requires an FAA Form 337 to be filed to document its installation is as noted right on the Form 337; “An alteration must be compatible with all previous alterations to assure continued conformity with the applicable airworthiness requirements.”

The whole reason that TC 4A24 came about in the first place is that the installation of multiple STCs (regardless of who owns them) or any other kinds of modifications to a single aircraft at some point triggers the provision of 14 CFR §21.19 which requires that any aircraft so extensively modified be re-certified under a whole new, comprehensive type design. In other words, installation of multiple McKinnon STCs on a single G-21 aircraft was deemed to be potentially incompatible with continued certification as a “Grumman G-21A” under ATC-654.

So too it must be noted that most if not all of the “McKinnon” type designs certified under TC 4A24 were more, in some cases much more, than just the sum of the modifications embodied by these STCs. In the obvious example of the very first new McKinnon “type design”, i.e. the model G-21C, there was no STC that separately covered the installation of its four 340 hp Lycoming GSO-480-B2D6 piston engines on legacy Grumman G-21A aircraft. Neither was there an STC to cover its unique “eyebrow” windows in the cockpit overhead. Most significantly, there was no STC that separately covered the installation of all of the various internal structural reinforcements by which the re-certified aircraft was able to operate almost up to the single-pilot qualified “Small” aircraft weight limit of 12,500 lbs. None of those modifications has ever been approved in the form of an STC for use or installation by a private owner “in the field” under the auspices of a “major alteration” under 14 CFR Part 43. And by the same token, none of the “other” so-called “McKinnon G-21G” aircraft conversions accomplished by someone other than McKinnon Enterprises Inc. was ever valid.

Once TC 4A24 came into being, the “McKinnon” aircraft produced under it, even though they were in fact actually converted from legacy Grumman G-21A airframes, were considered to have been newly “manufactured” under 14 CFR Part 21, Subpart F (Production Under Type Certificate Only) because the Production Certificate (PC no. 409) held by McKinnon Enterprises Inc. actually covered only the manufacture of the new parts that he used to convert the aircraft in question. Even so, McKinnon did have a PC (in other words an approved manufacturing “quality” system) and was thereby “certified” as an original equipment manufacturer or OEM under 14 CFR Part 21.

It is a fact that most of the G-21 series aircraft converted by McKinnon were so thoroughly “rebuilt” (by his own estimate as much as 80-85% of them was completely new) that they were literally “zero-timed” and all of their previous Times in Service as Grumman G-21A aircraft were wiped out. That is something else that cannot be done by a private owner installing STCs in the field under 14 CFR Part 43.

It is also true that in most cases, McKinnon did not license the use or installation of his STCs by others “in the field” as described earlier. For the most part, they were used or installed actually by McKinnon at his Sandy, OR facility. Legacy records also show that on the applications he made for some of those STCs, he indicated that they would be used "in-house" only and would not be used, sold, or licensed to anyone else in terms of the fabrication of the parts involved or their installation on subject aircraft.

In the final analysis however, it is best to view the various “McKinnon” G-21 series STCs only as the means by which certain individual features of the various models certified under TC 4A24 can be used or installed on legacy Grumman G-21A aircraft. Still, the provision previously noted on all FAA Forms 337 that “an alteration must be compatible with all previous alterations to assure continued conformity with the applicable airworthiness requirements” in combination with the restrictions of 14 CFR §21.19 effectively limit how many different “McKinnon” STCs can be installed on the same aircraft while still retaining its legacy certification.

In other words, private owners really ought to stop fooling themselves that these STCs were ever intended to be used the way that they have been using them.
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Re: Goose owners seem to do the wackiest things

Postby Rajay » Sun Jul 21, 2013 6:05 pm

Case 4: N642 has been IMPO one of the most problematic Gooses of the last 45 years or so. It seems to attract controversy like a magnet, but to the credit of its current owner, one of the things that he has already fixed was a “wacky” little modification made by its previous owner – who was in fact its first “private” or civilian owner after its many years of service with the US Navy and then the Bureau of Land Management (BLM) in Alaska.

In 1989, the General Services Administration (GSA) of the US Government on behalf of the Office of Aircraft Services (OAS) of the US Dept. of the Interior (USDI) declared N642 to be “surplus” property and put it up for sale via a GSA auction. On August 31, 1989, “McKinnon G-21C serial no. 1204” was sold to Jack Mark of Oshkosh, WI and re-registered to his property development and management company, MA Inc.

Jack Mark was a noted warbird enthusiast whose collection of aircraft included a P-51 Mustang, a T-6 Texan, a MiG-15, a couple of DHC-2 Beavers, a DHC-3T Turbine Otter on floats, a DC-3 configured as an executive transport with speed cowlings, panoramic “picture” windows and couches in the main cabin, a Grumman G-73 Mallard, a Beech King Air and Twin Bonanza (aka “T-Bone”), a Rockwell Sabre 65, a Canadair Challenger, a Fouga Magister, and several others. All in all, quite an impressive “stable” of aircraft…

Just a couple of years after buying N642, Jack Mark had his full-time aircraft maintenance staff “upgrade” it from its original McKinnon-installed 550 shp PT6A-20 turbine engines to 680 shp PT6A-27 engines apparently approved via a “field approval” supposedly on the basis of its similarity to the McKinnon model G-21E for which those same more powerful engines were an approved “factory” option under Section III of TC 4A24. During the course of that “upgrade” the original “bottom scoop” cowlings were modified by relocating the air intake scoops to the top of the cowlings, a mod that had proved necessary in course of actual service with other McKinnon turbine Goose conversions to reduce water ingestion.

The more powerful engines also necessitated the installation of the extended dorsal fin which had not been installed on N642 by McKinnon during its initial conversion in 1968 – even though that fin was technically a mandatory feature of the model “G-21C” type design as specified in McKinnon Master Drawing List (MDL) no. 7.

Note: That was just one little detail in regard to the fact that N642 was never properly certified as a model “G-21C” regardless of its supposed turbine engine conversion per STC SA1320WE. It actually lacked many other airframe details and features that were also “mandatory” features of the model G-21C type design as specified in MDL no. 7 – to which it has never actually “conformed”. Whereas the “real” model G-21C aircraft (N150M and N3459C, serial nos. 1201 and 1202 respectively) were certified up to 12,499 lbs, N642 (serial no. 1204) and its “sister” model “G-21C ‘Hybrid’ turboprop” conversion that became C-FBCI and later N660PA (serial no. 1203) were re-certified to only 10,500 lbs because they lacked the requisite internal structural reinforcements for that increased gross weight. They in fact actually conformed to the previous so-called “Grumman G-21A ‘Hybrid’ turboprop” conversions (N640 and G-ASXG) and to the later-certified / approved McKinnon model G-21E, all of which were essentially identical and also were re-certified to a maximum gross take-off weight of only 10,500 lbs.

In other words, THIS is NOT a "McKinnon G-21C":


But this is:


In any case, all of those modifications and “upgrades” done up to that point by Mark’s mechanics were relatively straight-forward and at least nominally “by the book”; in other words, so far – so good. The “wacky” part came along at some unknown point in time (because it was never documented, much less formally approved, in any way) when Mark had his guys cut away the relatively narrow companionway from the main cabin into the cockpit and reframe it as a significantly larger open archway not unlike the configuration of a smaller Grumman model G-44 series Widgeon. Approximately 60% of the area of main structural bulkhead at Hull Station 13 between the cockpit and the main cabin – the primary load-carrying structure to which both the front spar of the main wing and the aft mounting points for all of the main landing gear attached – was removed.

The rumor is that Jack Mark was a relatively large guy and had some trouble getting in and out of the cockpit of the Goose. Even so, there is no evidence in the aircraft’s official maintenance records that this bulkhead modification was in any way so much as evaluated much less actually formally approved by an aeronautical engineer (a DER for example) or by the FAA. (And that fact makes me really wonder about the integrity, experience, and ethics of the A&P/IA who signed-off its Annual inspections each year afterward!)

In the process of the bulkhead modification, all of the electrical equipment, voltage regulators, circuit breakers, and distribution busses as well as the fuel strainers, selector valves, and plumbing that had been previously mounted on the front side of that bulkhead were relocated and re-configured – mostly just squeezed or packed tightly into the remaining space in the corners of the bulkhead and the cockpit sides. In a couple of instances, there was evidence of chafing between wire bundles and other equipment and/or structure as a result.

Jack Mark died in June 2007 and his estate put N642 and several other aircraft in his collection up for sale. It eventually sold in April 2010 and was ferried (in spite of the dubious structural integrity of that main bulkhead) halfway across the country – from Oshkosh, WI to Everett, WA, but at least now it is undergoing a major restoration and one of the things that has already been “fixed” is that bulkhead. Photos posted on the “Goose N642” Facebook page show that it already has been repaired and restored to its proper and original configuration....

Photos of the relevant repairs are included in the public photo gallery on the "Goose N642" Facebook page here:

And if you bother to dig further back, you can also find photos of the improperly modified bulkhead before it was repaired.
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Re: Goose owners seem to do the wackiest things

Postby Rajay » Tue Aug 13, 2013 4:25 pm

Case No. 5

Grumman G-21A
serial no. B-97


A couple of days ago, I was reading the NTSB report regarding a little “accident” involving N741 on March 21, 1994. At that time, it was owned and operated by the Alaska Dept. of Public Safety and it was based in Juneau, Alaska.

The NTSB report in question, no. ANC94GA041, is online here:

The short and sweet of it is that the airplane “collided with terrain” on the Margerie Glacier on the west side of Mt. Fairweather in British Columbia, approximately 100 miles northwest of Juneau. The initial impact was at an elevation of approximately 8,900 feet MSL and the airplane finally came to a stop at about 9,650 feet MSL.

The pilot had been attempting to transit the vicinity of Mt. Fairweather (elev. 15,325 ft) and Mt. Root (elev. 12,680 ft) by flying through a “saddle” pass between the peaks. The elevation of the top of the “saddle” was about 11,000 ft MSL.

This “case” started off seeming to be just another example of the improper use of STC SA1751WE in which the main fuel tanks of a Grumman G-21A were modified from their original 220 US gallons to 336 gallons. Just as in the case involving N39FG, McKinnon's STC SA1751WE is not approved for use on a Grumman G-21A still certified under ATC-654 and it is nominally approved for use only on a McKinnon G-21CHybrid” turboprop or "Turbo Goose" that has been re-certified under TC 4A24 and that has also been converted to turbine engines per STC SA1320WE. Even so, it turned out that there was much more owner “wackiness” to be had in this particular case.

It seems that the primary reason for its failure to clear the terrain was determined to be that it was grossly overweight. The investigators and even the pilot as well seemed unclear about just what exactly the approved or certified maximum gross weight of this particular Grumman G-21A was supposed to be. There was documentation in the airplane’s flight manual, its maintenance records, and the ADPS operations manual which listed various weights from 8,800 lbs up to 9,000 lbs and even to 9,200 lbs.

Note: for reference, a “stock” Grumman G-21A is approved under ATC-654 up to 8,000 lbs. In Alaska only, there is a special FAA exemption for certain ex-military aircraft that allows them to exceed their certified maximum gross weight by as much as 15%. Because a “stock” Goose does not meet all of the climb performance requirements of that exemption, it is allowed only an 11.5% overweight exemption up to 8,920 lbs.

Under Section XVIII, page 23, of the Alaska Department of Public Safety aircraft operations manual, the maximum weight of Grumman G-21A Goose aircraft in the ADPS fleet was limited to 8,800 lbs for takeoff and 8,000 lbs for landing. In part, it stated that "These limits shall not be exceeded…." It is unknown if these regulations made any allowance for differences in equipment or STC modifications which can variously effect the performance and capabilities of different Grumman G-21A Goose aircraft.

For examples, a Goose with the Pan Air retractable wing tip float mod (the PBY style floats) per STC SA138SW is certified up to 9,000 lbs. and a Goose with the McKinnon retractable wing tip float mod (the single pole strut-type) per STC SA4-1467 is certified up to 9,200 lbs. The accident airplane, N741, was in fact equipped with the McKinnon retractable floats, so it should have been approved for operations up to 9,200 lbs.

At the time of its “accident” investigators calculated that the Goose, based upon its known empty weight of 6,717 lbs (which included a 41 lb life raft) the weight of the cargo (some 18 boxes of trial evidence) the pilot and 2 passengers, and full fuel (336 gallons = 2,016 lbs) weighed something like 10,202.8 lbs at takeoff from Juneau and that, after burning off approximately 400 lbs of fuel enroute, would have still weighed about 9,800 lbs at the time of its impact with the glacier.

The miscellaneous contents and cargo on the airplane that were not listed on the airplane's official weight and balance record, were inventoried and weighed at the Juneau airport on the day after the accident and they totaled 830.8 lbs. During a post-crash investigation interview, the pilot estimated that they weighed only “about 300 lbs” but he admitted that he had not performed any kind of formal weight and balance check while loading the aircraft. Besides the cargo and contents of the aircraft, the investigators estimated that the bilges in the keel of the aircraft contained a minimum of 10 gallons (80 pounds) of water which was frozen and could not be removed at the accident site.

In addition to being overweight, the investigators found other factors that would have degraded its ability to climb over the glacier. First of all, the landing gear was not fully retracted and the main wheels and tires were not completely stowed in the recessed wheel well compartments on each side of the fuselage. As a result, they were still fully exposed to the slipstream around the aircraft and would have produced a considerable amount of excess parasite drag.

The aircraft was also equipped with the McKinnon electric gear retraction system per STC SA4-1551, which provides the pilot with assistance in raising the landing gear. Normally, the original manually-operated system requires 40 – 41 turns of a hand-crank to accomplish full extension or retraction of the landing gear. With the McKinnon STC, an electric motor retracts the gear about 90 – 95% of the way. The hand-crank must be used to complete the final 5 – 10% of the cycle and fully stow the gear in the wheel wells on each side of the aircraft. The normal operating procedures in the G-21A Flight Manual supplement for this modification require that following an electrical retraction, the landing gear be manually cranked up until they are snug with the hull. They also must be visually checked to confirm that they are fully “up” and properly stowed in the wheel wells.

The pilot in command at the time of the accident was Claude E. Swackhammer, the manager in charge of the Aviation Division of the Alaska Dept. of Public Safety, and he held a Commercial Pilot certificate and a 2nd Class Medical certificate with limitations of glasses required for both near and distant vision.

The pilot’s logbooks and ADPS records indicated that he had flown 88.7 hours in a Grumman G-21A Goose and 6.8 hours in a Piper PA-31-350 Navajo during 1993 and the first part of 1994. No flights were recorded after November 27, 1993 until the day of the accident, March 21, 1994. In other words, the pilot had not flown at all in almost 4 months and technically speaking was not “current” in the Goose or any other airplane at the time of the accident – and yet he was carrying passengers and acting as PIC.

The pilot’s previous flight on November 27, 1993 was actually in the accident aircraft and was for the purpose of a requisite six month instrument check and an annual multi-engine land and sea proficiency flight checks. The check flight report indicated that 26 separate items were examined and were marked "satisfactory." No events or maneuvers were marked otherwise.

The Check Airman with whom the pilot had conducted his previous training and currency flight in the accident aircraft on November 27, 1993 held the role of Aircraft Supervisor with the Alaska Dept. of Public Safety in Anchorage and he was a civilian employee of the state who officially reported directly to Mr. Swackhammer – i.e. his boss. Records indicated that the pilot had been “checked out” by this same Aircraft Supervisor going back as far as 1979. Those same records also indicated that even though they had made as many as six different check flights together in 1992 and 1993, there were no records of any such check flights together between 1985 and 1992.

The Check Airman also told the investigators that although they were exempt from having to follow the FARs because the department’s aircraft technically qualified as “public-use”, their own internal operations manual and ADPS guidelines nevertheless still followed the requirements of FAR Part 91 in terms of basic operating procedures and pilot currency. In spite of that, the pilot told the investigators that he believed that he was “current” in the airplane and that he had not even bothered to use a checklist during the flight because he “knew the airplane.”

The pilot also stated that he believed that, based on his “knowledge” of the Juneau Sectional Chart, he needed to be at only about 9,000 ft MSL to clear the “saddle” between the peaks – you know, the one that actually topped out at about 11,000 ft…. He missed it by just a little bit, didn’t he? By about 2,100 ft at the point of initial impact!
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Re: Goose owners seem to do the wackiest things

Postby Rajay » Tue Aug 13, 2013 5:02 pm

In spite of the severity of the crash and the remoteness of the location near the top of the Margerie Glacier on the west side of Mt. Fairweather in March 1994, N741 was salvaged and repaired. It was later sold to Peninsula Airways (aka PenAir) and operated in the Aleutian Islands, specifically providing service to Dutch Harbor, and Unalaska.

On April 9, 2008, while attempting to land at Dutch Harbor, it collided with a large commercial truck that was transiting the runway environment via an access road that actually crossed the threshold of the runway. Traffic on the road was supposed to be warned of the approach of an aircraft via pilot-activated lights. The system also included gates that were supposed to block vehicles on the road in conjunction with the warning lights, but the gates were not operational – and had not been for more than a year, in spite of which, there was no NOTAM* warning published about it.

(*Notices to Airmen)

Ref. NTSB report no. ANC08FA050

According to the report, the pilot saw the truck but thought it had stopped before entering the runway threshold area. When he realized that it was still moving into his path, he attempted to go around, but the belly of the airplane collided with the top of the truck and the Goose crashed out of control onto the runway.

Of the nine people on board, the ATP-rated pilot and seven passengers sustained minor injuries and one passenger sustained serious injuries.

This is what the Goose looked like after the crash:

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Re: Goose owners seem to do the wackiest things

Postby Rajay » Sun Apr 06, 2014 4:50 am

They're at it again - Goose owners, that is. Well, one in particular...

Doing whatever he wants to do apparently without regard for the rules, etc…

Not so long ago, on the Facebook page which tracks the progress of the restoration of "Grumman/McKinnon" Goose N642 (except that it “officially” stopped being a "Grumman" in 1968) there was a new post that went something like:

First Test Fit of Cockpit Floor. (4 photos)
Walt has been working on making new cockpit floor panels, along with upgrading the seat attach points. Then the owner decided he wanted the co-pilot to have brakes. In the end replacing the floor panels encompassed the making of 21 new parts.

I'm just wondering how he's going to go (or went?) about putting co-pilot's brakes into his so-called “McKinnon G-21C” Turbo Goose.
Co-pilot’s brakes are NOT included as approved options under the official Master Drawing List no. 7 for the McKinnon model G-21C,
nor under the MDL for the turbine conversion per STC SA1320WE,
nor any other STC already approved for use in a “McKinnon” Goose aircraft certified under TC 4A24.
That means that they are classified as a “major alteration” and their installation must be explicitly approved accordingly.

The only already fully-approved (by the FAA in the US anyway) means by which co-pilot's brakes can be installed in a Goose of any kind is per STC SA2317WE – and it is applicable to and approved for use only on Grumman G-21A aircraft still certified under ATC-654. It is NOT applicable to or approved for use on a so-called “McKinnon G-21C” supposedly converted and re-certified under TC 4A24 – like N642 is.

I suppose that N642’s owner could develop and get approved a new STC of his own, but I find that unlikely that he would go that route. In a sense, it's already been done, so why would he go to the trouble that it would be if he did it correctly, according to the applicable regs, or with any kind of “originality” – i.e. without “stealing” or “plagiarizing” someone else’s existing designs?

It seems much more likely to me that he thinks that in some way he can copy the examples of installations of co-pilot's brakes in other McKinnon (or just so-called "McKinnon") turbine Goose aircraft. However, in almost every other example of co-pilot's brakes installed in a "McKinnon" turbine Goose, whether rightly so or not, they were installed supposedly also in accordance with STC SA2317WE - and even "copying" those examples without the explicit and expressed written permission of the current owner of that STC would be "stealing" someone else's property, probably both “real” and “intellectual”.

Note that according to...

14 CFR §21.120 Responsibility of supplemental type certificate holders to provide written permission for alterations.
A supplemental type certificate holder who allows a person to use the supplemental type certificate to alter an aircraft, aircraft engine, or propeller must provide that person with written permission acceptable to the FAA.


14 CFR §91.403 General
Para. (d) A person must not alter an aircraft based on a supplemental type certificate unless the owner or operator of the aircraft is the holder of the supplemental type certificate, or has written permission from the holder.

I am curious to see what he comes up with on his own without such written permission to use STC SA2317WE - or the engineering drawing(s) on which it is based.
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