Ahrens AR-404
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Hubertus Obst, e-mail, 03.12.2022 08:55

Jag är kusin till Kim Ahrens, hans mamma Ursula Ahrens var min mors sister. Jag kom till Kims föräldrar 1955 när Kim var 6 år gammal. Jag kan gärna ge dig mer information om du hör av dig. Varken Kims föräldrar, Kim och hans yngste bror Per är i livet längre. Med vänlig hälsning Hubertus Obst +46702703059

ulderico pace, e-mail, 28.07.2021 01:00

Hola Rafael

Podemos hablar del AR404?

Un cordial saludo.


ulderico pace, e-mail, 28.07.2021 00:58

Dear Rolf

We can talk about AR404?

Best regards.


ulderico pace, e-mail, 28.07.2021 00:57

Dear Rinah

We can talk about AR404 aircraft and your father?

Best regards.


ulderico pace, e-mail, 28.07.2021 00:52

Dear Adam

We can talk about the AR-404 project?

Best regards.


ulderico pace, e-mail, 28.07.2021 00:45

Dear Scott

Do you have any contact with Kim or his parents related AR 404?

Best regards.


Mario Overall, e-mail, 07.06.2021 17:02

Check the Ahrens 404 at the LAAHS website:


Remove the () from the URL above, since this website doesn't allow posting links.

Anonymous, 08.05.2021 01:53

I am Alan Aden here in Orlando putting a 2.0L in the C172. I have static test data that shows this uses 1/3 the fuel of the airplane or the car for that reason. Easy to put stock V8 engines in the plane for the same hp and probably 1/5 the cost of operating the turboprop and ours is almost emission free.

It looks like Peter's AR404 plans are gone. We have an interest in building that plane. Is that even possible anymore? I did know Peter quite well and visited his FW190 project several times. Even came up with 3 - 8 tracks showing it's progress that I gave to Gerd Muehlbauer at MT props. I knew Keller quite well who worked with him.

Let me see what you have to say about making the airplane. Al Aden

Ingmar Hedblom, e-mail, 02.10.2020 17:18

Thank you for the info. I would appreciate a picture of the aircraft at its present position in Puerto Rico.

Björn Rosengren, e-mail, 02.10.2020 11:42

The last time I was in Puerto Rico I saw it close to Mayaguez as a Piza shop.
Anyone know if any family members are still alive?
Björn Rosengren

peet, e-mail, 22.04.2020 17:51

hi billy, if you worked at the hanger in 1979, most likely we met.
we had to take a training , for 6 month before working on the floor.
i remember, after the flight, there were issues with the control cables.
it's strange, after 7 years, i found this website. fourty years, has pass,
hope to hear from you soon. bye

Scott Partei, e-mail, 10.04.2020 05:52

I worked for Kim in Reno Nevada for a year or so as a carpenter. 1983 or 4. The project was a house on Wilcox Ranch road in Palomino Valley.

I know Kim was a good man and loved his family.
He spoke of the 404 fondly and as an aviation enthusiast myself I appreciated him.

Good luck to his family

Dennis Dinzeo, e-mail, 14.08.2015 19:39

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 Daz-Saldaa, e-mail, 25.10.2014 18:03

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 Daz-Saldaa, e-mail, 25.10.2014 18:03

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 Daz-Saldaa, e-mail, 25.10.2014 18:03

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 Daz-Saldaa, e-mail, 25.10.2014 18:02

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, e-mail, 04.03.2013 01:12

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, e-mail, 18.01.2013 10:37

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

Leif Hallberg, e-mail, 23.06.2012 14:11

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? - dont 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, e-mail, 17.04.2012 05:11

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, e-mail, 12.02.2012 20:24

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, e-mail, 12.12.2011 19:14

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

RAFAEL MEDINA RODRIGUEZ, e-mail, 30.10.2011 06:08

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, e-mail, 19.06.2011 23:23

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, e-mail, 13.12.2010 15:10

Could this aircraft design be resurrected?

Rinah Ben Gershon, e-mail, 12.11.2010 07:20

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.

Rolf Rosn, e-mail, 19.05.2010 13:26

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 Rosn

Martin Wienert, e-mail, 06.04.2010 03:44

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

Jose Nieves, e-mail, 26.02.2010 18:53

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, e-mail, 02.02.2010 02:31

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

susan cakmak/ahrens, e-mail, 01.02.2010 04:26

I am a family member of the Ahrens and appreciate the work that went into this aircraft and the creativity of peter and kim in particular and its rewarding to hear there are people out there who acknowledge their originality in this project

susan cakmak/ahrens, e-mail, 01.02.2010 04:25

I am a family member of the Ahrens and appreciate the work that went into this aircraft and the creativity of peter and kim in particular and its rewarding to hear there are people out there who acknowledge their originality in this project

Robert F. Neefus, e-mail, 17.10.2009 03:36

In 19780-81, I was flying for Sun International out of San Juan, P.R. At that time, my boss had invested in the Ahrens 404 and had been promised the first two flyable production planes. Sun International wents defunct in 1982 or so and I was long gone by then. Saw the prototype in the hanger at Ramey. Compared to the Beech 18 and Islanders I was flying, this was going to be a major step up. Ahhh, what dreamers can do!

Robert E. Frank, Colonel, USAF, e-mail, 05.10.2009 10:12

I was the USAF Program Director in 1983-'85 that expressed an official to purchase 18 Ahrens 404 for use by the USAF in Europe.

However, the PR Bank was allegedly influenced by the Spanish Government to stop payment on the Ahrens loan. When the bank refused (without warning) to release the final SBA-guaranteed loan payment, it also used armed guards to confiscate all of the engineering drawings, tools, and aircraft components that were required to complete the FAA certification. Ahrens should have been able to find alternative funding for the final step of certification, but due to the unjustified bank seizure, it was impossible for Ahrens to bid as the sole US candidate in competition with two European light cargo aircraft (Spain-backed and Ireland-backed aircraft).

I did everything I could with numerous USAF 4-star general backing to try and straighten matters out, but the international politics were vicious and effective. It was a serious loss for the global aviation markets as the engineering of the Ahrens 404 was a breakthrough in engineering value and low-cost life-cycle operating capabilities.

If anyone is interested in more details, please send email to safe_mail@cox.net I also would really love to talk to Peter Ahrens and his sons again. They were true pioneers and patriots.

BILLY BLACK, e-mail, 21.07.2009 21:13


Basil Meecham, e-mail, 03.07.2009 20:33

Does anyone know how to get in contact with Capt. Peter Ahrens. The last time I saw him was in Deland Florida and he had just returned from New Zealand.

Lynn B Stites, e-mail, 28.02.2009 07:42

I knew Peter Ahrens quite well, I was an attorney with a law firm and I represented him and his company in many matters. I was an aerospace engineer, and understood the 404 well; I even drove a few rivets in it when it was being built in Oxnard. I wonder where Peter, kim are now? Lynn Stites

Nigel Prevett, e-mail, 11.09.2008 20:17

Clearly the spec is wrong, should be 4 engines not two...

Anyway, a fuselage survives on the side of a house a few miles east of Las Vegas McCarren airport, on west side of Sandhill road between Harmon and Flamingo cross streets. It's painted all white now but fuselage without tail matches the airliners.net pic of N1028G on scrapheap mentioned in other comments. Is this the one?

curt Schr�der, e-mail, 19.08.2008 15:21

When the Peter Ahrens left Purto Rico he came to Sweden and started a company together with several persons (including me) to go omn with the next generation 404. It became C180 constructed by Kim Ahrens and a prototype were build in Malmoe. For several reason the project couldnt be fullfilled in Swede, but it was a very god project and Peter and Kim made a fantatic work in Sweden

Graeme Sambell, e-mail, 14.06.2008 16:10

I am a personal friend of the Ahrens family and I saw the prototype in Oxnard just before they flew it. Kim was very proud of it and so he should have been as it was a good aircraft and the lean concept was ahead of its time.
It is so sad to see the photo of it on the scrap heap as it certainly had potential and would, even today be filling a niche that few other aircraft do today

Jose R Gonzalez, e-mail, 04.05.2008 05:08

I had the opportunity of meeting Capt. Peter Ahrens a very capable and resourceful man. His sons were geniuses.

The demise of the AR-404 was a sad occasion for Puerto Rico and aviation but specially to the Ahrens family who spent many hours trying to make a dream come true only to have the powers in Washington and elsewhere kill the plane. Fortunately there is a photo of frame N1028G in Airliners.net at McCarran International in Las Vegas evidence that it was totally airworthy. You can checki it out at http://www.airliners.net/photo/Ahrens-404/0154260/M/


Jose R Gonzalez
San Juan Puerto Rico

Alfredo herrera, e-mail, 04.02.2008 22:57

It is interesting and what a coincidence you all talking about this aircraft AR404. I was conducting research about this aircraft to talk about it in my Master level Aircraft Design course at Worldwide Embry-Riddle Aeronautical University and found your discussions very enlightening. Well, let me tell you; I was the only aeronautical engineer Ahrens Aircraft had before they closed. I worked side by side with Kim Ahrens who was the original designer. This company used Lean concepts to the maximum. I would say if any aircraft company wants to learn lean they should research about Ahrens Aircrafts frugal design and manufacturing approach.

Aircraft one flew several hours and its performance was well. Any issues were corrected on the fly by Kim Ahrens and his team. I can really write a dissertation about this company and its design and manufacturing approach. If you need any additional information dont hesitate in contacting me at aherrerapadua@hotmail.com. The people of Puerto Rico can be proud of been involved in the development of this aircraft as well as its follower the Bromon BR2000. I also, worked for them at the beautiful Ramey Base in Aguadilla.

Aisen Lopez, e-mail, 04.01.2008 03:46

Intersting info. I do remember the Ahrens 404 flying at ramey. The last time I saw the airfoil of the remaining aircraft it was sitting on top of a small hill in front of Aguada beach. An ex-girlfriend told me that it was owned by a person known as Chuco Ramos and he had planned to use it as part of a theme park. I think it still there.
I'm really interested in the model for flight simulator, please design it for FS2004 also and let me know when it's available.

avia.russian.ee, 13.08.2007 15:59

To Antonio Acosta:

Jim Winchester "The World's Worst Aircraft", 2005
it's not my words, it's the name of the book. You should read more carefully next time.

avia.russian.ee, 13.08.2007 15:57

To Antonio Acosta:

<> - it's not my words, this is the name of the book. You should read more carefully next time.

Gerardo M. Hernandez, e-mail, 12.08.2007 13:07

You said just two the true is they almost flies two aircraft one paint in blue an the other in yellow plus two other fuselage that never been finish and was used for stress test. I know where is the resting place of two fuselage the yellow one and one that was used for testing. The other stress fuselage end as snack bar in road PR-2 in Aguada but isn't there any more and I don't know where is it. I'm making an effort to salvage this fuselage because it historical value, to preserved it as static display. I'm working on aircraft model for simulator, for at least fullfill the dream of see the aircraft made on P.R. take to the sky. I'm president of PRINAIR historical association and invite you to visit www.prinair.org thanks.

Antonio Acosta, e-mail, 08.08.2007 00:27

Well you say it is the world's worst aircraft, but in that plane were the heart of all employees, like my dad, they build that aircraft from nowhere, its very easy now to how worst was but it flyed ! unfortunetly the company closed, but all people who work on that Ar-404 they got the experience to build something from scrath and it work, an experience that maybe you dont have, and then you called the world worst aircraft.
dont quite remember the first flight because i was 1 year old but i can remember my dad telling me how was the flight, and it flies very smooth, and for last . . . i see companies with billions, bulding aircraft with a lot of experiences and they really sucks !

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