Reading the OSH NOTAM without losing the will to live
The AirVenture 2026 NOTAM is the single most important document you will read all summer if you plan to fly into Wittman Regional (KOSH). It is also dense, long, and unforgiving if you skim it. EAA typically publishes the official NOTAM about six weeks before the show, which puts the 2026 release in early-to-mid June. Pull it directly from EAA at https://www.eaa.org/airventure when it goes live. Aggregator sites and pilot forums often host stale prior-year copies that look right at first glance and will get you in trouble.
The NOTAM is structured in roughly six sections, and you should know which one you need before you open it.
- General information. Show dates, controller positions, expected volumes, contact details. AirVenture 2026 runs July 20 to July 26.
- VFR arrival procedures. This is the part most pilots care about: Fisk arrival, Warbird arrival, Seaplane arrival, helicopter procedures, and the holding patterns at Rush Lake, Green Lake, and Endeavor Bridge.
- IFR procedures. Approach reservations, IFR-to-VFR transitions, and how to file when KOSH is at saturation.
- Mass arrivals. Bonanzas, Cessnas, Mooneys, Cirrus, Pipers. If you are not part of one of these, you do not need to read this section in detail, but you do need to know when they are inbound so you stay clear.
- Special operations. Banner tow, ultralight, balloon, parachute. Useful if your routing puts you near the show airspace at non-arrival hours.
- Ground handling. Parking, camping, fuel, taxi diagrams. This section is critical for first-time arrivals.
Print the pages that apply to your aircraft and your arrival type. Tab them. Highlight the frequencies and altitudes the NOTAM specifies for this year. Do not work from the prior year's notes.
Fisk arrival, the basics
The Fisk VFR arrival is the busiest visual procedure in the world during AirVenture. Conceptually it is simple. You fly to a railroad track and antenna at Ripon, Wisconsin, then follow the railroad northeast at a published altitude and airspeed in single file. At Fisk, controllers identify your aircraft by paint scheme and give you a runway assignment with a "rock your wings" call to confirm the ID. From Fisk you fly the published transition to your assigned runway at Wittman.
The framework that does not change year to year:
- Single-file from Ripon to Fisk. No formation. No overtaking. If you catch the aircraft ahead, slow down or S-turn. If you cannot maintain spacing, exit the procedure and re-enter at Ripon.
- Two altitudes and two airspeeds. The NOTAM publishes two stacked tracks for fast and slow aircraft. Use the one that matches your aircraft, not the one that matches your ego.
- Listen only. Fisk approach uses a one-way frequency from the ground to you. You do not transmit on it. You acknowledge instructions by rocking your wings. Read-backs clog the frequency and make the controller's job harder.
- ATIS is mandatory before Ripon. You must have the current ATIS information before reaching Ripon, every time.
Specific frequencies, altitudes, and airspeeds change in the NOTAM each year. Pull them from the 2026 document and brief them as part of your arrival plan. Do not memorize last year's numbers.
When ADS-B Out should be off (and why)
The long-standing OSH guidance is that ADS-B Out should be off, or set to anonymous mode, on the Fisk arrival. The reason is operational: hundreds of aircraft compressed into a narrow corridor at low altitude will saturate ATC's display with overlapping ADS-B targets, alerts, and conflict warnings. Controllers at Fisk identify aircraft visually and run the procedure by eye. ADS-B clutter does not help them and can actively hurt them.
The current year's NOTAM specifies the exact configuration EAA and the FAA want. Read it and follow it. The principle:
- ADS-B Out on the Fisk arrival: typically off or anonymous.
- ADS-B In: leave it on. You want the traffic picture in your cockpit even if you are not broadcasting your own position.
- Transponder: configuration is published in the NOTAM, often Mode C with a specific squawk for the procedure.
For Garmin GTX 335/345 boxes, anonymous mode is selected from the transponder setup page (the menu item is usually labeled "Anon" or "ADS-B Anonymous"). Avidyne AXP340 owners can enable anonymous mode via the configuration menu when no flight plan is filed. If your installation is older or the option is buried, brief the workaround on the ground, not at 1,800 feet over Ripon. If you fly an aircraft with no easy way to disable ADS-B Out, the NOTAM will tell you what to do.
What your portable receiver actually sees in the saturation event
Honest answer: a lot. On the Fisk corridor on a busy Saturday, a portable ADS-B receiver may display two hundred or more targets within a few miles. Your tablet will look like a swarm. This is the moment to be clear about what the device is for.
The targets that matter are within roughly 1 NM laterally and ±500 feet vertically. Beyond that, every target on your screen is noise relative to your immediate decision-making. A good receiver and a good app will declutter or visually de-emphasize distant traffic, but you should still expect more clutter than you have ever seen in normal flying.
Use the device for backup awareness. Fly the procedure visually, look outside, and listen to Fisk approach. The portable receiver tells you when something is closing on you that your eyes have not picked up yet, which is genuinely useful in a crowd. It is not a primary separation tool in this environment, and no portable receiver should be sold as one. For a deeper look at what supplemental traffic adds and where its limits are, see the portable ADS-B receiver with CO detection and our piece on 5 common situational awareness gaps in general aviation.
If you want your traffic feed to behave properly during the show, configure the app before you launch. Our guide on setting up your portable ADS-B receiver for ForeFlight, SkyDemon, and beyond walks through the connection steps and the display filters worth tuning.
CO risk on a hot taxi line
The angle most pilots miss at OSH: the taxi line, not the flight. Picture a hot July afternoon at Wittman, ground temperature in the high 80s, fifty aircraft ahead of you on the taxiway, and your engine running at low idle with the cowl flaps where you set them for cruise. The heat muff is hot. Airflow through the cabin is poor. The exhaust system is under more thermal stress than usual. This is the textbook scenario for cabin CO levels to rise.
A passive CO card on the panel will not warn you. By the time it darkens, you have already been breathing elevated CO for a while. An active sensor with an audible alarm, whether it's a CO Guardian unit or a SkyRecon-class detector with an integrated buzzer, will alert before symptoms set in. Typical alarm thresholds are around 50 ppm sustained, which is well below the level that produces noticeable headache or fatigue. Open a window if you can, lean for ground operations to reduce exhaust enrichment, and do not ignore the alarm because you are six aircraft from the ramp.
A pre-departure checklist for OSH
- Pull the official 2026 NOTAM from EAA the day it drops; brief every page that applies to your aircraft.
- Brief Fisk arrival procedures with a paper backup, including hold points at Rush Lake, Green Lake, and Endeavor Bridge.
- Plan fuel for 30+ minutes of holding at Ripon. Saturday inbound delays happen.
- Set ADS-B Out per NOTAM (typically off or anonymous on the Fisk arrival). Verify on the ground.
- Set ATIS in standby and have a pen ready to write the information letter and runway assignment.
- Brief diversions: KFLD (Fond du Lac), KATW (Appleton), KMSN (Madison) are the standard alternates. Fond du Lac is the closest and the most likely to be busy.
- Pre-flight the CO sensor. If it is a portable, charge it. If it is panel-mounted, confirm the self-test passes.
- Brief emergency procedures specific to the Fisk arrival, including the published exit and re-entry instructions if the procedure breaks down.
Frequently Asked Questions
When is AirVenture 2026? July 20 to July 26, 2026, at Wittman Regional Airport (KOSH) in Oshkosh, Wisconsin.
Where do I get the official AirVenture NOTAM? From EAA directly at https://www.eaa.org/airventure. The 2026 NOTAM is expected to be published in early-to-mid June 2026. Do not use prior-year copies.
Should I have ADS-B Out on or off for the Fisk arrival? Historically, off or anonymous to avoid saturating ATC's display. The current year's NOTAM specifies the exact configuration. Verify it before you launch.
What if the Fisk arrival is closed when I get there? The NOTAM publishes hold points at Rush Lake, Green Lake, and Endeavor Bridge with specific altitudes. If the procedure is fully closed (weather, saturation, or a runway incident), divert to KFLD, KATW, or KMSN and wait for the procedure to reopen. Do not free-lance into the Class D.
Do I need a special endorsement to fly into Oshkosh? No. There is no special endorsement required. You do need to have read the NOTAM, briefed the procedures, and be current and proficient in your aircraft. Realistically, if you have not flown an unfamiliar high-traffic visual procedure before, fly with someone who has.
Can I fly into AirVenture without prior experience flying into busy events? You can, but it is not the place to learn under pressure. If this is your first time, fly the procedure on a weekday rather than a Saturday, arrive early in the morning when volumes are lower, and consider riding along with a more experienced AirVenture arrival before you fly your own.
Pull the NOTAM the day it drops
The 2026 NOTAM is the single document that ties the whole arrival together. Read it the day EAA publishes it, brief it twice, fly the procedure as written, and leave room in your fuel and your schedule for the unexpected. See you at the show.
