A little while ago, I uploaded a photo of N77AQ (McKinnon G-21G Turbo Goose s/n 1205) but FlightAware automatically labeled it as a “Grumman G-39” and didn’t give me a way to edit or correct that. It was a Grumman G-39 (ex-USN JRF-5) until 1969 when it was converted and re-certified under FAA Type Certificate No. 4A24 (as opposed to the original Grumman TC for the G-21A series, no. 654) by McKinnon Enterprises Inc. of Sandy, OR. At that point, it was no longer a Grumman anything.
We automatically tagged it as a G21 because that’s the aircraft code it has been operating under. In the FAA publications G21 has a number of possible manufacturer/model names:
Grumman | G-39 Goose
Grumman | G-38 Goose
Grumman | G-21A Goose
Grumman | Goose
Grumman | JRF Goose
Now that the photo is tagged as aircraft type G21T, it the photo is labelled as a MCKINNON G-21G Turbo Goose.
Does that mean that ICAO flight planning codes take precedence in determining the labeling / identification? Originally, I identified N77AQ as what it is, a (McKinnon) model G-21G; did the FlightAware system read that as a G-21A with a flight plan equipment code of /G? (as in G21/G, whatever that might be - I don’t have an AIM handy right now.)
ICAO is the only “place” that the identification “G21T” is meaningful. McKinnon had STCs to make turbine conversions out of Grumman G-21A as well as his own originally piston-powered G-21C and G-21D aircraft. McKinnon’s G-21E and G-21G models were certified from the beginning as new turbine aircraft (even though, of course, he did convert them from legacy G-21A aircraft.)
The slant G equipment code has nothing to do with the aircraft being a G-21G model or not.
If you tag a photo with a tail number, we do our best to also tag the aircraft type based on the aircraft type code it has been operating as recently. In this case N77AQ has been filing G21, so we tagged it as that. You should have had no problem changing the aircraft type tag to G21T.
For each aircraft type there can be multiple submodels/license builds/marketing designations/etc that used the same code.
For example G21T can be:
MCKINNON | G-21G Turbo Goose
MCKINNON | G-21E Turbo Goose
MCKINNON | Turbo Goose
We default to the first option in our list, so we label any G21 as “Grumman G-39 Goose” and any G21T as “MCKINNON G-21G Turbo Goose”. If there’s some other name that best represents the majority of G21/G21T aircraft, we’re happy to take feedback and update the displayed names.
Just out of curiosity, why do you use “G-39” or “G-38” at all? Those are typically considered just “design” numbers, not officially “model” numbers. In any event, the FAA recognizes only the model designation “G-21A” and all ex-military Gooses that have been re-certified and registered as civilian aircraft are recognized as such. I realize that the original civilian versions of the Goose (actual models G-21 and G-21A) were in the minority in terms of overall production numbers, but the fact of the matter is that all ex-military models and even the original 12 plain “G-21” aircraft were all supposedly brought up to G-21A standards for civilian registration in the US - if they lasted long enough. Of course, the most numerous examples of any Goose were the US Navy’s JRF-5s, accounting for 184 out of the total production of 345.
When the owner of N77AQ, for example, files a flight plan identifying it as a “G21/R” first of all, it should be identified as a “G21T/R”, but secondly it is still incorrect for FlightAware to label it as a “Grumman G-39”. Although it is now a McKinnon G-21G (having been re-certified under a completely different type certificate, TC 4A24), prior to its turbine conversion in 1969, it was an ex-USN JRF-5 (s/n B-62) and as such it was originally a Grumman model G-38.
Goose production actually broke down as follows:
12 models G-21 (all supposedly brought up to full G-21A standards)
30 models G-21A
1 model G-26 (US Navy XJ3F-1 prototype for later JRF series)
26 models G-31 (USAAC OA-9)
12 models G-21B (pure flying boats built for Portugal)
204 models G-38 (five JRF-1, five JRF-1A, ten JRF-4, and 184 JRF-5 for the USN)
10 models G-39 (seven JRF-2 and three JRF-3 for the USCG) and
50 JRF-6B* contracted for the British (although not all were delivered to them)
*Most reference sources call the British JRF-6B aircraft Grumman “G-38” aircraft as well, just like all of the USN aircraft, but if they were similar to any of them, it was only to the first five JRF-1 because all of the rest of the USN aircraft had camera wells (almost 3 ft diameter holes) in their bellies but the British JRF-6Bs did not.
So, defaulting to “G-39” just because it was the last or highest “design” number is not correct in almost every case and in every case, the FAA recognizes “G-21” and “G-21A” as the only actual, certified “models” of Grumman Goose aircraft. In fact, only two “G-39” aircraft still show up in any current civilian registry; ex-JRF-2 serial no. 1077 is still flying in Canada as C-FUAZ for Pacific Coastal Airlines in British Columbia and ex-JRF-3 serial no. 1085 (last registered as N12CS) is now hanging from the ceiling of the National Museum of Naval Aviation in Pensacola, FL.
We had to pick something and last usually isn’t too bad. I’ve updated G21, G21M, and G21T to reflect the most generic option available:
G21 Grumman Goose
G21M McKinnon Goose
G21T McKinnon Turbo Goose
On the flight page we display the aircraft code the pilot files and the best name we have for that code. N77AQ now reads “Grumman Goose (twin-piston) (G21/R” since the pilot chooses to file G21. I realize the pilot is filing incorrectly, but we’re not going to change it. The registration page says 1969 MCKINNON G21G since that’s what the FAA registry database says.
Probably needn’t bother with “G21M” for McKinnon Goose (i.e. piston G-21C or G-21D as opposed to turbine G-21E and G-21G ) because the ONLY one still in existence is half-disassembled and derelict in Bangladesh - McKinnon G-21C, serial no. 1202, registered since 1971 as S2-AAD - and it’s not going anywhere anytime soon.
And just to further confuse things, not all of the turbine Gooses that were ever built were “McKinnon” Gooses. In addition to those that were actually re-certified by McKinnon under his TC, there were others that remained “Grumman” Gooses - just with a McKinnon turbine engine STC installed - AND still others that were not “McKinnon” in any way. Two Gooses were converted to turbines by Alaska Coastal-Ellis Airlines about the same time that McKinnon was doing his. The two ACEA turbine Gooses, N95431 (s/n 1164) and N4773C (s/n B-52) were much simpler than the McKinnons; they were essentially un-modified except for the PT6A engines mounted on the original Grumman nacelles from the previous R-985 installations. Both aircraft were much later re-converted back to R-985 engines and both still exist, although one is in Australia (s/n 1164 is now VH-MBA) and s/n B-52 is now N42GL in Wisconsin.