# Missing Numbers Minds vs HSI

The clearest difference is update cadence: HSI at every 2 months against Missing Numbers Minds's every 5 months. HSI also leads on iOS requirement (16.4 vs 26.1). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Missing Numbers Minds sells 2 one-off in-app purchases and HSI sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

Missing Numbers Minds ships an update every 5 months, HSI every 2 months. The most recent releases landed on October 26, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | Missing Numbers Minds | HSI |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.7 (6 ratings)](https://appshunter.io/ios/app/hsi-instrument-approach-sim/id1278956934/reviews)** |
| Number of ratings | — | **6** |
| Positive reviews | — | 81.8% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 2 months** |
| Monetization | — | Free with in-app purchases |
| Size | 4 MB | 16 MB |
| Requires iOS | 26.1 | **16.4** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Juan Fullana](https://appshunter.io/developer/692107580) | [NATHAN STANKEVICIUS](https://appshunter.io/developer/923933206) |

## What reviewers say

### Missing Numbers Minds

[App page](https://appshunter.io/ios/app/missing-numbers-minds/id980949764)

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Donation for maintenance. | $0.99 | one-time |
| Extra for develop and maintenance | $0.99 | one-time |


### HSI

[App page](https://appshunter.io/ios/app/hsi-instrument-approach-sim/id1278956934)

Practice instrument approaches with realistic HSI displays and customizable navigation modes. Import your own approach plates to fly procedures as published. This app is designed for student pilots, instrument-rated pilots, and flight instructors.

**Highlights:** Import custom PDF approach plates, Realistic HSI instrument display, Multiple navigation modes (VOR, TACAN, LOC, NDB), Fix to Fix (Point to Point) training, Adjustable speed control for practice, Privacy-focused with zero data collection

**Features:** macOS Compatibility, Family Sharing, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Upgrade | $9.99 | one-time |


## Frequently asked questions

### Is Missing Numbers Minds free?

Missing Numbers Minds is free to download, with in-app purchases available.

### Is HSI free?

HSI is free to download, with in-app purchases available.

### Do Missing Numbers Minds or HSI have ads?

Neither Missing Numbers Minds nor HSI shows ads.

### Which is updated more often, Missing Numbers Minds or HSI?

Missing Numbers Minds ships an update every 5 months, and HSI every 2 months. Most recently, Missing Numbers Minds was updated on October 26, 2026 and HSI on October 29, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*