# CAT eBook Viewer vs SkyTest BU/GU Preparation App

The clearest difference is price: CAT eBook Viewer at Free against SkyTest BU/GU Preparation App's $89.99. CAT eBook Viewer also leads on iOS requirement (7.0 vs 15.0). On update cadence, ads, in-app purchases and device support there is nothing between them.

CAT eBook Viewer is free to download; SkyTest BU/GU Preparation App costs $89.99 up front. Neither carries in-app purchases, so what you see is what you pay.

CAT eBook Viewer ships an update every 5 months, SkyTest BU/GU Preparation App every 3 months. The most recent releases landed on October 10, 2026 and October 15, 2026 respectively.

## The numbers

| Metric | CAT eBook Viewer | SkyTest BU/GU Preparation App |
| --- | --- | --- |
| Price | **Free** | $89.99 |
| Rating | **[1.0 (1 ratings)](https://appshunter.io/ios/app/cat-ebook-viewer/id448922100/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | — | 40.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 3 months** |
| Monetization | **Free** | Paid |
| Size | 36 MB | 429 MB |
| Requires iOS | **7.0** | 15.0 |
| Devices | iPad | iPad |
| Age rating | 4+ | 4+ |
| Developer | [CAT Civil Aviation Training](https://appshunter.io/developer/448922103) | [Aviation Media & IT GmbH](https://appshunter.io/developer/504134961) |

## What reviewers say

### CAT eBook Viewer

[App page](https://appshunter.io/ios/app/cat-ebook-viewer/id448922100)

Access customized aviation training materials for JAR/EASA pilot licenses. View content for aeroplanes and helicopters, including PPL, IR, CPL, and ATPL.

**Highlights:** View customized teaching material, JAR/EASA PPL, IR, CPL, ATPL content, Aeroplane and Helicopter modules, Civil Aviation Training material

**In-app purchases:** none


### SkyTest BU/GU Preparation App

[App page](https://appshunter.io/ios/app/skytest-bugu-preparation-app/id775751981)

Prepare for pilot aptitude tests with a comprehensive suite of training modules covering attention, memory, spatial orientation, psychomotor skills, math, logic, physics, technical comprehension, and English. Features include detailed explanations, customizable difficulty levels, performance analysis, and progress tracking to optimize your training outcome.

**Highlights:** 41 training modules, Bilingual (English/German), Interactive demos, Customizable difficulty, Performance analysis, Progress tracking, Training Assistant

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

**In-app purchases:** none


## Frequently asked questions

### Is CAT eBook Viewer free?

CAT eBook Viewer is free to download, with no in-app purchases.

### Is SkyTest BU/GU Preparation App free?

SkyTest BU/GU Preparation App costs $89.99, with no in-app purchases.

### Do CAT eBook Viewer or SkyTest BU/GU Preparation App have ads?

Neither CAT eBook Viewer nor SkyTest BU/GU Preparation App shows ads.

### Which is updated more often, CAT eBook Viewer or SkyTest BU/GU Preparation App?

CAT eBook Viewer ships an update every 5 months, and SkyTest BU/GU Preparation App every 3 months. Most recently, CAT eBook Viewer was updated on October 10, 2026 and SkyTest BU/GU Preparation App on October 15, 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.*