The APU is unable to properly cool the cabin
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https://www.pprune.org/tech-log/135762-fokker-f-100-a.html?
Among crews who flew the aircraft, the Fokker 100 developed a reputation for marginal ground cooling performance in hot weather, especially with a full passenger load. This wasn't necessarily because the APU itself was unreliable. It was more that the entire ECS, including the packs supplied by the APU, had limited cooling capacity in high ambient temperatures.
On hot days (30–40°C / 86–104°F), the APU could struggle to provide enough bleed air for both air conditioning packs to cool a fully loaded cabin before engine start.
It's a feature, not a bug
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This is actually something that affects other aircraft irl as well. The A320 also struggles to maintain cabin temperatures in hot conditions. Not as drastically as the F100 though, but sometimes 26°C is the lowest you can get when outside temperatures are very high. The APU and packs in MSFS addons are oftentimes a bit overpowered in this regard.
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This is realistic when on the ground.
Both the F28 and the F100 were designed for temperate Northern European summers and struggled here in the US, especially in the south.
If anything, I think the packs are actually too powerful once you take off. Today the cabin was 34C when I started the APU and it only got down to 31C by takeoff. After takeoff by around 4000 feet it was 19C. Would've been warm a lot longer!
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One of the pilots on our testing team, who operated the aircraft in a hot climate, said they used to call it Satan's Sauna because of how ineffective the air conditioning could be on hot days!
Mark - Just Flight
Thank you very much for your comments! I really appreciate them. I wasn't aware that the air conditioning was so weak
@Mark said in The APU is unable to properly cool the cabin:
One of the pilots on our testing team, who operated the aircraft in a hot climate, said they used to call it Satan's Sauna because of how ineffective the air conditioning could be on hot days!
Mark - Just Flight
Would it be possible to have an EFB option for pre-conditioned air? This would allow us to cool down the cabin on a hot day. It's awful to start boarding with a cabin temperature of over 40°C
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Hello,
First of all, thank you very much for this amazing add-on! I'm really enjoying it.
I noticed that with the APU turned on, it's impossible to keep the cabin cool in hot weather. I don't know whether the APU is too weak or whether the effect of the open passenger door is exaggerated. However, the APU should be able to maintain a cabin temperature of around 22°C, even when the outside temperature exceeds 30°C.
Greetings
Tim@Tim-HH Hi Tim. I flew the F100 for 10 years and we called it "The Dutch Oven" because in the summer, it was terribly hot once the doors were open for passenger embarkment and disembarkment as well as catering service at door 1R. Once the engines were started, it would cool down very slowly until the pressure in the duct reached about 32psi, which it didn't anywhere near idle thrust. If I was in a line of traffic and stopped and it was safe to do so, I would push the throttles up to get that 32psi in the supply duct and then the air cycle machines (packs) would begin to put out cooler air. Once the airplane climbed out it would slowly cool the airplane to comfortable levels, but it took some time to do that. I hope this information helps.
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@Tim-HH Hi Tim. I flew the F100 for 10 years and we called it "The Dutch Oven" because in the summer, it was terribly hot once the doors were open for passenger embarkment and disembarkment as well as catering service at door 1R. Once the engines were started, it would cool down very slowly until the pressure in the duct reached about 32psi, which it didn't anywhere near idle thrust. If I was in a line of traffic and stopped and it was safe to do so, I would push the throttles up to get that 32psi in the supply duct and then the air cycle machines (packs) would begin to put out cooler air. Once the airplane climbed out it would slowly cool the airplane to comfortable levels, but it took some time to do that. I hope this information helps.
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@Flys787 Very interesting! Thank you very much for sharing this insight
It makes you wonder why the F100 is/was so popular in Brazil and Australia.
@Tim-HH It was popular a lot of places because it did what the airlines needed it to do, at the time, better than other options. American Airlines was the largest single operator of the F-100, which does not seem to make sense. Once the CRJ came along, that is the way they went. However, that 100 seat aircraft niche was dominated by the Fokker 100 for a good bit of time. Financial issues (Dalmer-Benz) were the ultimate doom. I read that there was a company that as late as 2014ish was trying to bring it back into production with updated engines. Amazingly capable aircraft.
