Go ahead, ask me how I know what a vernatherm is.
As mentioned in previous posts, we started having engine issues the day before we left the Bahamas. The engine seemed to overheat way too quickly and easily, despite being built with two oil coolers and being flown and tested in Australia in 40-degree heat.
After flying too low for my comfort through the last bit of the Bahamas, we cleared customs and immigration and started the flight to the Dominican Republic.
For this flight, we flew from Matthew Town (MYIG) to Sosua (MDPP), following the Hattian Coast. Anxiety was high as we flew into Haitian airspace, unable to contact the controller because of a mountain but it was all good, they had no issue with us.
After getting settled in Sosua we asked around and got given the contact of an AME in Santiago. We reached out and decided on a time we would fly to Santiago to have the AirVan checked out.
Before heading to Santiago we had done some research and my Dad had started to speculate that the issue was with the vernatherm.
Now I had gone over the basic parts of the engine in ground school and all that, but I had no clue what a vernatherm was, so if you are scratching your head as to what it is let me help. The vernatherm is essentially a temperature-controlled bypass. When it reaches a certain temperature it will open and allow oil to pass into the oil coolers.
So, back to Santiago; we took the cowling off and started inspecting everything. While we wished nothing was wrong with GIPU, a problem with the vernatherm would probably be the best outcome out of the possibilities. If the vernatherm wasn't the issue then it would probably mean that it was something much more time consuming and expensive to fix. The AMEs agreed that the vernatherm is a good place to start.
Once the vernatherm was pulled out and we decided to test it. In theory, our vernatherm should open when it reaches 85 degrees Celcius. We started by heating it with a heat gun before deciding to put it in boiling water.
Dropping the vernatherm in some water, we slowly brought it to a boil in the coffee pot, monitoring the temperature as we went.
After being in bubbling and boiling water for over 3 minutes it still didn't spring open as it should. This confirmed that the vernatherm was not working properly.
While this wasn't good news, I was still relieved as it meant that it was relatively easy to fix. Next step was finding a replacement.
Lucky for us the AME knew a friend that had a vernatherm in stock in Puerto Rico so we would only have to wait a week! So with the new vernatherm waiting to be shipped, we put the old one back in and flew back to Sosua to wait.
After the part arrived it was as simple as testing the new vernatherm (which sprung open as soon as it reached 85 degrees Celcius ) and then installing it. The AirVan was once again climbing like a "homesick angel" as my dad described it.
Overall I was extremely glad the engine was once again performing as it should be. Flying low over ocean crossings with not the best weather and limited options to climb was not my ideal situation, but we made it work and it all turned out alright. Plus I now know what a vernatherm is! There's more to learn every day.
After the AirVan had been to the doctor, we were ready to leave the D.R, and our next stops were the 3 G's, Guadeloupe, Grenada and Guyana before continuing down through South America.
A "vlog" from our TikTok about the adventure!
NOTE: The Dominican Republic is very General Aviation friendly, even with lots of commercial flights. The parking fees for small planes are low, if not nonexistent and the controllers are absolutely awesome. Once you clear customs and immigration accessing your plane or flying around is simple; even in crazy busy airports like Punta Cana. A tip would be to check flight arrivals and plan to fly in the morning, especially in Punta Cana (after 3pm it gets much busier with jets). Punta Cana is easy to fly into with small general aviation planes. ATC is great, and there is little to no parking and airport fees.