Coming soon to the App Store.Coming soon to the App Store. In development by the maker of DETENT.
Say it out loud.
Speak real ATC calls and get graded word by word, on device, in under a second.
One-time purchase
Tower Cessna one two three alpha bravo, runway two six, cleared touch and go.
Youcleared touch and go runway two six cessna one two tree alpha bravo
12 of 13 exact, 1 accepted variant.
- exact
- accepted variant
- wrong or missing
Radio calls only get comfortable once they leave your mouth. SQUELCH turns your iPhone into a patient tower: hold to talk, make the call, and watch every word come back graded in under a second. All of it on device.
No account. No subscription. No cloud.
- Price: One-time purchase
- Device: iPhone, iOS 26+
- Speech: 100% on-device
- Live mode: MSFS 2024 via bridge
Mic fright is the last gate.
Every student pilot knows the moment: hand on the mic, call rehearsed, and the freeze anyway. Reading about radio calls does not fix it. Saying them out loud does. SQUELCH gives you a tower that never sighs, never rushes you, and grades every word so the real frequency stops being scary.
See it grade
Hold. Speak. Release.
Four steps from mic fright to muscle memory.
Tower Cessna one two three alpha bravo, runway two six, cleared touch and go.
Youcleared touch and go runway two six cessna one two tree alpha bravo
12 of 13 exact, 1 accepted variant.
- exact
- accepted variant
- wrong or missing
- 01
Pick a scenario
Choose a lesson: pattern work at a towered field, non-towered calls, picking up ATIS, more as the curriculum grows.
- 02
Hold to talk
Press and hold the PTT bar like a real yoke switch. Haptics click on key and unkey.
- 03
Make the call
Say the whole call out loud. A live transcript follows your voice as you speak.
- 04
Read your grade
Release and the call is graded word by word against FAA phraseology, variants accepted, errors flagged.
Tolerance with a hard edge
Niner or nine. Tree or three.
Real pilots do not all sound like the AIM, and rigid graders are the reason most radio trainers feel like a spelling test. SQUELCH accepts documented real-world variants of the same call. Tolerance has a hard edge, though: it applies to pronunciation, never to meaning.
- niner ↔ nine
- tree ↔ three
- fife ↔ five
- two seven ↔ twenty seven
- with information delta ↔ with delta
Youcleared touch and go runway two four cessna one two three alpha bravo
Runway two four is not runway two six. Wrong slots are flagged, never auto-corrected.
A wrong runway or a wrong callsign is always caught, never auto-corrected. Detecting the dangerous readback is the product.
Workflow
How it works
Four steps from mic fright to muscle memory.
- 01
Pick a scenario
Choose a lesson: pattern work at a towered field, non-towered calls, picking up ATIS, more as the curriculum grows.
- 02
Hold to talk
Press and hold the PTT bar like a real yoke switch. Haptics click on key and unkey.
- 03
Make the call
Say the whole call out loud. A live transcript follows your voice as you speak.
- 04
Read your grade
Release and the call is graded word by word against FAA phraseology, variants accepted, errors flagged.
SQUELCH runs on iPhone with iOS 26 or later. Live mode is optional: pair the DETENT bridge on your PC to fly Microsoft Flight Simulator 2024 while SQUELCH prompts and grades your calls.
Curriculum
A curriculum, not a phrase list
Scenarios play out like real flights: you hear the situation, you make the call, the lesson moves with you. Start in the pattern and work outward.
Towered pattern work
Ground, tower, pattern entries, touch and goes, full stop. The calls every student flies first.
Non-towered fields
Self-announce on CTAF: taxi, upwind, crosswind, downwind, base, final, clear of the runway.
ATIS and ground
Copy the letter, make the call with information current, taxi with a readback that gets graded.
Turn-by-turn feedback
Every turn shows what was exact, what was accepted, and what was wrong, with the canonical call to compare.
Live mode
Live mode: fly it for real in MSFS
Pair SQUELCH with the DETENT bridge on your PC and your simulator becomes the scenario. Fly Microsoft Flight Simulator 2024, and SQUELCH reads your live situation over your own Wi-Fi: airport, runway, position in the pattern. It prompts the call you would actually make right now, and grades what you say.
- 01
Fly
Any flight in MSFS 2024, from pattern laps to a cross country.
- 02
Bridge
The same lightweight bridge DETENT uses, over your own network. Nothing leaves your LAN.
- 03
Prompted
SQUELCH derives your situation and prompts the right call at the right moment.
- 04
Graded
Speak it out loud on your iPhone and get the word-by-word grade instantly.
Advantages
Why SQUELCH
Why SQUELCH, in full
SQUELCH is built by the developer of DETENT on the same principles: instrument-grade feel, total privacy, and no strings. You buy it once, you own it, and your voice never leaves the phone.
100% on-device speech
Transcription and grading run entirely on your iPhone with Apple's on-device speech engine. Airplane mode is a supported configuration.
Graded word by word
Every call comes back marked: green for exact, amber for an accepted variant, red for wrong or missing. You see exactly which slot needs work.
Errors get caught
A wrong runway or callsign is never smoothed over by fuzzy matching. Catching the dangerous mistake is the whole point.
Tolerant of real phraseology
Niner and nine, tree and three, twenty seven and two seven all count. You are graded on the call, not on sounding like a robot.
Graded in under a second
Release the push to talk and the grade is on screen in under a second. Drill a call twenty times without waiting on anything.
No account, no cloud
No sign-up, no subscription, no telemetry. One purchase, yours forever.
Roadmap
What's next
SQUELCH ships focused and grows deliberately. Here is where it is headed.
Towered and non-towered pattern curriculum
LaunchLive mode with the MSFS 2024 bridge
Launch windowFlight following and Class C/B transitions
NextIFR clearances and copy-readback drills
NextController voice replies
Exploring
The people
What simmers are saying
Reviews from students and CFIs will land here as pilots get their hands on SQUELCH at launch.
SQUELCH is made by Dayel Ostraco, developer of DETENT, a GA pilot and simmer for over 20 years.
Support
FAQ
- Do I need an internet connection?
- No. Speech recognition and grading run on the phone. There is no account, no cloud, and airplane mode works fine.
- Is my voice recorded or uploaded?
- Audio is processed on device by Apple's speech engine and never leaves the phone. There is nothing to upload it to.
- Will it accept how pilots actually talk?
- Yes. Documented real-world variants are accepted: niner or nine, tree or three, twenty seven or two seven. Rigid graders are the problem SQUELCH exists to fix.
- What happens if I read back the wrong runway?
- It gets flagged, every time. Tolerance applies to pronunciation, never to a semantically different token. A trainer that quietly corrects your wrong runway is training the wrong habit.
- Which devices does it run on?
- iPhone running iOS 26 or later.
- Does it work with Microsoft Flight Simulator?
- Yes. Live mode pairs with the DETENT bridge on your PC and prompts the calls that match your actual flight in MSFS 2024.
- How much will it cost?
- One-time purchase, priced at launch. No subscription, ever.
- Do I need a CFI or a medical to use it?
- No. SQUELCH is a practice tool for anyone who wants to sound comfortable on the radio, from pre-solo students to rusty pilots.