Gear
You don't need much. An iPhone, a USB-C audio adapter and one cable put the intercom on the record. An ADS-B receiver is optional.
What you need
An iPhone
Any iPhone with iOS 18 or later. The adapter plugs into USB-C, which iPhone 15 and newer have. Older iPhones with a Lightning port need a different adapter, and we haven't tested one.
An iPad works too. A Wi-Fi only iPad has no GPS of its own, so choose one with cellular if you want the track.
A USB-C audio adapter
It must be class compliant: the iPhone uses it as an audio input with no extra app or driver. When it's plugged in, the Preflight screen shows "USB" and the adapter's name in green, and the level bar moves when people talk.
A cable from the intercom's recording output
Look for an output meant for a recorder on your intercom or audio panel, and check its manual. The cable runs from that output into the adapter.
Set the level once. If the summary says the audio clipped, or the recording screen shows a yellow LOUD, turn the intercom's recording level down. When the adapter allows it, the app also shows a gain slider next to the level bar.
Power for long flights
A plain adapter takes the iPhone's only USB-C port, so the phone can't charge while it records. Start with a full battery.
Preflight shows how many minutes of recording the battery has left, and the app sends a silent notification at about 20 minutes left. In our early tests an iPhone 15 Pro Max with the intercom adapter used about 10 to 11 percent of its battery an hour, with the screen mostly off.
To charge while you record, you need a USB-C adapter with a power passthrough port. We haven't confirmed one that works yet.
A place for the iPhone
Put the iPhone where it can see the sky, for a clean GPS track. Mount it, and route the cable, so nothing blocks or interferes with the controls, instruments, radios or intercom. When the iPhone is mounted, CaptainVoice also records motion.
Without an adapter
CaptainVoice still records. It uses the iPhone's own microphone, shows "Built-in mic" in yellow, and never stops you from starting.
The trade-off: with headsets on, the iPhone microphone mostly hears the engine. ATC and the intercom will be faint or missing. It's fine for a test on the ground, not for a real debrief.
CaptainVoice uses a Bluetooth microphone only if you pick it on Preflight. In the aircraft it has the same trade-off as the built-in microphone.
For a ground lesson in a quiet room, the iPhone microphone works well. You can also pick an outside USB or Bluetooth microphone, such as a conference speaker, on Preflight.
ADS-B receivers (optional)
With an ADS-B receiver on the cockpit Wi-Fi, CaptainVoice also records your own position, pressure altitude and attitude from the receiver, and the traffic around you (within about 10 nm and 3,000 ft). When the receiver gives pressure altitude and attitude, CaptainVoice uses them instead of the phone's own sensors.
CaptainVoice is built for Stratux and Sentry. Other receivers that send GDL90 may work. We're still testing both receivers in the aircraft.
Next to ForeFlight
A Stratux sends its data to each device on its Wi-Fi. On one iPhone, though, only one app can receive that data at a time, usually the one that started listening first. ForeFlight's traffic display is the one you fly with, so ForeFlight comes first.
- Best setup: ForeFlight on an iPad, CaptainVoice on the iPhone, both joined to the Stratux Wi-Fi. Each device gets its own copy of the data.
- One iPhone for both: open ForeFlight first and check that it shows traffic. Then slide to record in CaptainVoice, and check ForeFlight again. If ForeFlight shows no traffic, stop the recording before takeoff and tell us. In this setup CaptainVoice usually records no ADS-B data, and that's fine: ForeFlight keeps its traffic.
CaptainVoice listens for ADS-B only while it records, never on the Preflight screen.
No internet on the receiver Wi-Fi
A receiver's Wi-Fi has no internet. Keep cellular on so Chunks can upload during the flight. If they can't, they wait on the phone and upload after landing.
Questions about gear
Write to [email protected] with your intercom and adapter, and we'll help you get a clean recording.