Ahrens AR-404
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Ahrens AR-404

The AR-404 utility aircraft: was the brainchild of a US company who set up a production facility in western Puerto Rico. The company made various claims for the AR-404, including that it could be certified under the same standards as the large jetliners, but in one year rather than four. Suggested uses included fish spotting, Anti-Submarine Warfare, gunship, parachute dropping and training. Through obtaining money from the Puerto Rican government, it was said 1000 locals with no previous aircraft making experience would soon be turning out four per month. A mysterious US government investigation into the company dragged on, preventing the development money and loans going through. The project was abandoned and the principals decamped elsewhere. Only two AR-404s were built. The first prototype was last noted serving as a snack bar.

Jim Winchester "The World's Worst Aircraft", 2005

 ENGINE2 x 420hp Allison 250-B17B turboprops
    Take-off weight7710 kg16998 lb
    Wingspan20.12 m66 ft 0 in
    Length16.08 m53 ft 9 in
    Height5.79 m19 ft 0 in
    Max. speed315 km/h196 mph

Comments1-20 21-40
Dennis Dinzeo, 14.08.2015

I was stationed at the Coast Guard Air Station Hangar adjacent to the Ahrens hangar in 1978-1979 and I recall Mr. Ahrens coming over to examine the HH3F helicopter sponsons. Lo and behold the AR404 closely resembles the H3, at least in the landing gear department. We also heard somewhat anecdotally that the first test flight scared the bejesus out of the test pilot because the empennage turned out to be a bit undersized. I also remember the AR404 snack bar on the PR2 roadside in Aguada or Anasco some years later.

Sixto Díaz-Saldaña, 25.10.2014

Puerto Rico was wronged by stopping the Ahrens airplane. By now we would be in the map as aviation manufacturers and developers and exporters and creators of jobs and opportunities.

Sixto Díaz-Saldaña, 25.10.2014

Puerto Rico was wronged by stopping the Ahrens airplane. By now we would be in the map as aviation manufacturers and developers and exporters and creators of jobs and opportunities.

Sixto Díaz-Saldaña, 25.10.2014

Puerto Rico was wronged by stopping the Ahrens airplane. By now we would be in the map as aviation manufacturers and developers and exporters and creators of jobs and opportunities.

Sixto Díaz-Saldaña, 25.10.2014

Puerto Rico was wronged by stopping the Ahrens airplane. By now we would be in the map as aviation manufacturers and developers and exporters and creators of jobs and opportunities.

billy, 04.03.2013

If anyone would like to see video of the AR404 flying in Puerto Rico please email me. I have restored from VHS tape to digital video of the test runs and flights from the Puerto Rico days.


Ingmar Hedblom, 18.01.2013

Does anybody know what happened to the first Ahrens prototype N404AR? Is it still preserved someplace?

Leif Hallberg, 23.06.2012

During the time Peter an Kim was engaged with KM180 at Sturup (Malmoe Airport Sweden), I was an employee at formerly SATT Communication in Stockholm (now a part of SAAB AB). Peter had met our managing director at Farnborough and persuaded him to sponsor KM180 with materials for the aircraft cablings and some human assistance - it was me! My assignment was to manage the cablings work togethe with two hired british guys. But - the work had not proceed very far when LFV (the Swedish Air Authority - now SWEDAVIA) flagged it off. Serious lack of documentation and not following the stated qualification program was said as reason. Rumors that SAAB could be involved are - in my opinion - just rumors. My part was intended to mostly be done on private consulting basis and my expected salay was of coarse lost. As "plaster on the wound" I got all purchased special Sourieau connectors as a gift from our MD. These are still in its original bags in my basement store! Interested to buy them? - don´t hesitate to send me a mail! Peter has passed away I remember his enthusiasm, his capability to engage and persuade people and not least his one and only joke: Edison invented the light - Lucas the darkness (apropos the bad quality of Lucas components).
Rest In Peace Peter!

Judy (Clegg) Bennett, 17.04.2012

I knew the Ahrens family from 1968 to 1980's. My mother was a nurse (Rosina Clegg) at the hospital where Peter, Kim, Eddie, and Per worked when they first moved to California. Peters kids were all teenagers back then inviting me to the beach and teaching me surfing. The whole family (Gudrun included) were the smartest people I knew...and the most generous. I remember Per dancing with me in Peters living room to Simon and Garfunkle. Kim wrote a love letter to his girlfriend using "Bridge over troubled Water" as inspiration at the time. I was an artist and did a seascape painting for Peter. Gudrun lent me a report on the Wright Brothers to help me with a report I was doing. I named my daughter after Kim as that family was such a big influence on me. I am so sad to hear that "Captain A" as we lovingly called him and Kim have passed away. They were truly Renaissance men. These guys believed in their dreams and were fierce and fearless and the coolest family I ever knew! God bless them and their family!Love,Judy

Jose R Gonzalez, 12.02.2012

Reminiscing about the AR-404 and Peter Ahrens, a favorite topic, I recall one afternoon perhaps in 1978 that I accompanied him to a meeting at local FAA facilities with some officers that had flown in from Atlanta to question him about the plane and discuss certification issues etc. I recall vividly how Capt. Ahrens replied, with complete details and total knowledge of the topic. The FAA officials commended him on the thoroughness of his replies and his knowledge.

I enjoyed the meeting; now, after all these years I am still grateful to Capt. Ahrens for the opportunity of being with him at the meeting. He was a good man and had a great plane.

At one point in time, the Ahrens Aircraft manufacturing plant employed over 1,000 people at the former Ramey Base in Aguadilla PR.

Adam Elmholt, 12.12.2011

Hi everyone,
I was involved in Capt. Peter Ahrens project "KM180" in Sweden between 1985-87. The company "Scandinavian Aircraft Construction AB" under the leadership of Capt. Ahrens had managed to get the support of the Swedish government to pursue the development of a pressure cabin 4-engine turboprop multi-purpose aircraft, a development of the AR-404 made by Kim Ahrens.
To make a long story short the project was later stopped by the Swedish Aviation Authority due to lack of documentation.
Capt. Ahrens thought that SAAB had something to do with the withdrawal of the project permission.
At that time a full body of the "KM180" was already built, plus a mock-up of wood.
The project was then moved to Puerto Rico, Ramey Airport.
After that I lost track, but if anyone has question about the project in Sweden, let me know!
Adam Elmholt


Hello to all
Rafael from Sebastian Puerto Rico , first student at Ramey Aguadilla as Airframe Mechanic, the Arens-404 best of it line ,best dual duty , aircraft ,ask me I do not
forgotten those days,months,year ,nest to kim and family.

Rut Alonim, 19.06.2011

Dear Curt, Thank you for all your help on the SAC 180. Kim was the senior design engineer for the BHT 407 in Mirabel, Quebec and was working to ground the project long enough to fix the FADAC system problem that was caused because the harness cable that controlled the fuel flow was wired backwards. He was found dead in the bathtub full of water with severe brushing on his back. The original coroner told me that he had been in the cold water for 18 hours - Therefore he died on Sept. 11, 1995. He loved the project and refused to allow it to be delivered because the problem tested out to show it was sure to cause fatalities. Six months after his death, the FAA in the US and in Canada grounded the project until they could determined the cause. After all the children were settled and completed their highschool requirements, started their own lives and had university, I took the plans for the SAC180 and delivered it to a design engineer in Israel as a gift to the State of Israel. That was in 2000, the same year my granddaughter, Helena, was born in Ystad. The next year I acelerated my ascension to Israel as Helena had developed typhoid and needed a grandmother close by. The plans of the AR404 were the property of Jesse but I am not sure which way they went. It was a very difficult time after Kim's death. He was a magnificent person, no matter how angry I was with him, if he started a discussion on any subject I was captivated. How I loved him. Barbara

Gabe, 13.12.2010

Could this aircraft design be resurrected?

Rinah Ben Gershon, 12.11.2010

I'm the daughter of Kim Ahrens, formerly called Tanya Ahrens. It's so comforting to hear the kind words spoken about my father and grandfather, both deceased. As I grew up around both of them, I realized what true geniuses and pioneers the Ahrens men were, both in aviation and in lean manufacturering. It fills me with great pride to see that even if their dreams never formed into reality, the people that worked with them were positively influenced in their own lives. Anyone interested in information about the family can contact me at my email address.

Mr. Milton, 31.07.2010

Specializing in Defense Supplier Indenting, Importer, Exporter & Trading House
Ref: BTC/July-31 Date: 31/07/10

To :

Email :

Attn : Export (International Division.)

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Sl Items Description Qty
01. Utility Air Craft (AC) Fixed Wing (Twin Engine) 02 Units

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Rolf Rosén, 19.05.2010

I have no comments about the aircaraft. It is so that I had a company in Sweden when Peter and Magda was hier We calculated on his airplane and constructed the landing gear Is he or Magda alife. Should be intersted to hear from them
Kyllikki and Rolf Rosén

Martin Wienert, 06.04.2010

Made some 404 research - am interested to locate N1028S.
Any help is very much appreciated!

Jose Nieves, 26.02.2010

I did work for Ahrens back in 1978, and I admire the Aherens Family specially Capt. Peter, for hes perseverance in following his dream. I have located the AR 404,N1028G, N1028K and the N1028s. if you have any information related to this, and willing to share, please e-mail me.

Harald Mortimer, 02.02.2010

I am also a family member... My mom Gudrun sent me to this site. Very cool plane indeed!

1-20 21-40

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© The AR-404 had four rather small motors. A twin-engined version with two 1000hp Garrett turboprops was planned but never built.

© It was said the AR-404 could run on diesel fuel as easily as it did on jet fuel, which cost about 10 times as much.

© One proposed version was a carrier-capable transport to replace the C-2 Greyhound in the carrier onboard delivery (COD) role.

© The AR-404's competitors were such aircraft as the Shorts 330, GAF Nomad and even the C-130. Costs per seat-mile were quoted as lower than any direct competitor.

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