Airport of the Week: KL35 - Big Bear Airport - Come for the views, stay because your plane can't climb!

Flying into Big Bear City Airport isn’t just scenic, it’s a masterclass in mountain flying. Nestled high in the San Bernardino Mountains of Southern California, Big Bear City Airport (KL35) is a destination that promises breathtaking views and a truly unique aviation experience. At an elevation of 6,752 feet, it’s a gateway to alpine adventures and a popular spot for pilots seeking a mountain flying challenge. But with that beauty comes a demanding environment, where the weather can change in the blink of an eye, making real-time, accurate weather data not just a convenience, but a critical tool for flight safety.

A High-Altitude Haven with a Weather Temperament

Big Bear City Airport has a single asphalt runway (8/26) stretching 5,850 feet. While seemingly ample, the high elevation and surrounding mountainous terrain demand a pilot’s full attention and respect. The air is thinner here, and that means aircraft performance is significantly different.

What makes Big Bear particularly challenging, especially for the less experienced private pilots, is the rapid fluctuation in weather conditions. The mountain environment is a breeding ground for microclimates. A calm, clear morning can quickly give way to afternoon winds, turbulence, and a significant spike in temperature.

One of the weather challenges at KL35 is density altitude. For the uninitiated, density altitude is the pressure altitude corrected for non-standard temperature. In simpler terms, on a hot day at a high-elevation airport like Big Bear, your aircraft will perform as if it’s at a much higher altitude. This translates to:

• Reduced engine power: Less dense air means less oxygen for the engine to burn.
• Decreased propeller efficiency: The propeller has less air to "bite" into.
• Longer takeoff rolls: Your aircraft will need more runway to get airborne.
• Reduced rate of climb: Gaining altitude will be a much slower process.

The DA Trap: Don't Take My Word For It

This isn't just a theoretical discussion. This phenomenon is so well-known that pilots have a name for it: the "DA trap." A recent YouTube aviator, Outside the Cockpit, shared their experience during a flight to Big Bear. Upon landing, the density altitude was a manageable 4,000 feet. However, after just an hour on the ground, the weather had changed enough to push the density altitude to 6,000 feet. This dramatic shift serves as a powerful reminder of how quickly conditions can deteriorate, turning a routine takeoff into a potentially hazardous situation.

If you need more evidence, here is what redditor archerdynamics had to say about L35.

Big Bear in SoCal is a notorious DA trap. It can get pretty hot up there in the summer and result in DAs over 10k', and many pilots have run into trouble over the years when they fly up from LA or OC with a fully loaded plane when it's cool in the morning and then realize they don't have the performance to get out in the hot afternoon. Fortunately most seem to figure it out when doing calcs on the ground and end up leaving once it cools down in the evening, but it's still enough of an issue that we were specifically warned about it when I was doing my PPL ground school in the LA area.

Since we are talking about density altitude, one experienced pilot (old_flying_fart!!) shared this pearl of wisdom.

I find many people only underestimate density altitude once.

You underestimate it, you go flying, and you find your trusty IO-360 is wheezing and gasping and your wing is flying through a weird mixture of nothing and sludge.

Then you either die, and you never underestimate it again, or you scare the bejeezus out of yourself, and you never underestimate it again.

Closing Thoughts

Suffice it to say, make sure you are well versed in weather and your airplane's performance when flying to KL35. I have personally not been to the Big Bear area, but looking at their website they seem very welcoming. There is even a free trolley that runs every 30 minutes, 7-days a week.

Here are some fun videos about flying into and out of KL35.

• Big Bear City Airport (L35) | The ULTIMATE Pilots Guide by Outside the Cockpit
• Best Pilot Accessory! | Fun Day Trip to Big Bear L35 | ETWOW GT Scooter Review by SoCal Flying Monkey

Some More Dangerous GA Airports

If you are curious about more airports with dangerous weather for general aviation private pilots, check out my post on reddit. As a bonus, Jerry Wagner actually replied in that thread! =)