ASTB Prep vs CBDR
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
ASTB Prep
Prepare for military aviation exams with comprehensive lessons, practice tests, and realistic simulators. Track your progress and study offline for the ASTB-E and OAR tests.
- Comprehensive lessons for ASTB-E and OAR
- 1200+ sample test questions with explanations
- Adaptive practice tests
- Realistic PBM simulators (DLT, UAV, TI, RC)
- Offline content access
- Progress tracking
- Controller support for simulators
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ASTB PREP is a comprehensive study tool for the ASTB-E and OAR military aviation exams, created by a former Naval Officer. Full Access is available as a one-time in-app purchase. Whether you are preparing for Navy, Marine Corps, or Coast Guard aviation selection, ASTB PREP gives you the tools to study efficiently and build confidence before test day. FREE FEATURES • Create a free account • Access introductory lessons covering exam overview, structure, and study strategies • Track your study progress • Sync your progress and access with your ASTB PREP account FULL ACCESS • 81 comprehensive lessons with review sections across all 7 ASTB subtests • 140+ flashcard decks for rapid knowledge reinforcement • 1,200+ sample test questions with detailed explanations • Unlimited adaptive practice tests that target your weak areas • Dichotic Listening Test (DLT) simulator • UAV tracking simulator • Terrain Identification simulator • Rear Cockpit simulator • Hardware-enhanced PBM training for a more realistic practice experience • On iPhone and iPad, train with intuitive on-screen controls or compatible Bluetooth game controllers, including supported Xbox and PlayStation controllers • Performance coaching tools • All content is available offline after download, making ASTB PREP ideal for deployment, travel, and other low-connectivity environments STUDY WITH YOUR ACCOUNT Full Access is tied to your ASTB PREP account. Sign in with the same account to keep your access and study progress synced and available wherever your account is supported. EXISTING CUSTOMERS If you previously purchased ASTB PREP, your access is preserved. Simply sign in or create an account to link your Full Access. ALL 7 ASTB SUBTESTS COVERED • Math Skills Test (MST) • Reading Comprehension Test (RCT) • Mechanical Comprehension Test (MCT) • Aviation and Nautical Information Test (ANIT) • Naval Aviation Trait Facet Inventory (NATFI) • Performance Based Measures (PBM): DLT, UAV, TI, RC • Biographical Inventory with Response Validation (BI-RV) Also covers all 3 OAR subtests: MST, RCT, and MCT. Account required. Free to create. Privacy policy: https://www.iubenda.com/privacy-policy/24362764
CBDR
This app trains junior deck officers and watchstanders in essential radar watch skills, including contact evaluation, COLREGS classification, and generating contact reports. It features a live radar scope, generated scenarios for various navigation situations, and drills for recognition and maneuvering.
- Live radar scope with vectors and trails
- Generated navigation scenarios
- COLREGS classification
- Contact report scoring
- Maneuvering board drills
- Recognition drills
- USCG Rules of the Road test bank
- Offline group testing
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CBDR is a training app for junior deck officers. Twelve subjects cover radar, Rules of the Road, maneuvering boards, navigation calculations, positioning, tides and currents, shiphandling, vessel identification, weather and waves, maritime law, visual signals and testing. RADAR. Practice contact assessment, CPA, relative motion and contact reports. Use the scenario library or build a picture of up to six contacts to share by code or QR. Give a report by voice with on-device recognition, or type it. A Rule 17 drill stops the scope where the stand-on vessel must keep her course and speed, where she may act, and where she must. Eleven explainers and a tuning simulator cover the signal, receiver controls and propagation. RULES. Practice with the 954-question Rules of the Road bank and read the governing Navigation Rules passages in the app. Optional Guided Practice directs questions toward material that needs more work. Lights, shapes and sound-signal drills include their rules and explanations. MANEUVERING BOARD. Work nine Pub 1310 problem types with step-by-step constructions, including CPA avoidance, stationing, limiting range, bearings-only TMA, advance and transfer, and wind. Practice a generated problem, enter your own values, or print a problem set with blank boards and an answer key. CALCULATIONS. Work time, speed and distance, compass conversion, mental minute rules, visibility, anchoring, time zones, ETA and speed of advance. POSITIONING. Step through visual and radar fixes, soundings, celestial navigation, inertial navigation, GPS, AIS, the fathometer, running fixes, dead reckoning, and set and drift, with illustrated plots built step by step. Study aids to navigation with an animated range and recognition practice. Search the bundled Chart No. 1 plates. Star Finder identifies navigational stars from the camera's star pattern without asking for, computing or storing your position. TIDES AND CURRENTS. Animated lessons on tides, reversing flow in San Diego Bay, rotary currents, and hydraulic flow in the Cape Cod Canal. A separate lookup retrieves NOAA and Canadian Hydrographic Service station predictions, saved for offline use and export. SHIPHANDLING. Animated lessons show how a propeller and a rudder work, the pivot point, tugs, and twisting off a pier. Man-overboard recoveries step through the Anderson, Williamson and racetrack turns. Hydrodynamic lessons cover bank cushion and suction, interaction alongside an oiler, and squat, drawn with their pressure fields. VESSEL IDENTIFICATION. Recognize ship classes and vessel types from silhouettes, photographs, or both. This feature is marked Beta. Source and license credits accompany the images. WEATHER AND WAVES. Bowditch's weather on a rotating globe, from the wind belts and fronts to fog, tropical cyclones and Buys Ballot's law. Waves on a three-dimensional sea: how they form, travel, shoal and break. MARITIME LAW. Six pages from UNCLOS, SOLAS, MARPOL and STCW: where the rules come from, the maritime zones, passage rights, flag and port state, and warships and assistance at sea. Each step names the article it follows. VISUAL SIGNALS. Signal flags and pennants, hoists decoded from Pub. 102's examples, and Morse by light from a signal lamp or a ship at night. TESTING. Build a test from any topic in the app, with calculations as multiple choice or typed answers, questions from every explainer page, and questions of your own. Host and join group tests by QR or text code, entirely offline, and export the instructor's record as PDF or CSV. Print a test with its answer key. Hosted exams reveal answers after the test is finished. Training works offline. The station-prediction lookup uses the internet when requested, including Apple's map service. No account, advertising, analytics or tracking. Training settings, optional question-level practice progress, custom scenarios, saved tests and saved predictions stay on the device. There is no history of session scores.
Screenshots
Verdict
The clearest difference is in-app purchases: CBDR at none against ASTB Prep's 2. CBDR also leads on update cadence (weekly vs fortnightly). ASTB Prep's advantage is ratings volume (450 vs 5). On price, rating, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. ASTB Prep sells 2 one-off in-app purchases. CBDR asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 4.9 for ASTB Prep against 5.0 for CBDR. That said, the two scores are not equally well evidenced: ASTB Prep has 450 ratings behind it against 5, so its average is the more settled of the two.
ASTB Prep ships an update fortnightly, CBDR weekly. The most recent releases landed on November 3, 2026 and October 31, 2026 respectively.
| Parameter | ASTB Prep | CBDR |
|---|---|---|
| Price | Free | Free |
| Rating | 4.9 (450 ratings) | 5.0 (5 ratings) — better |
| Positive reviews | 93.6% of reviews | — |
| Number of ratings | 450 — better | 5 |
| Update frequency | Fortnightly | Weekly — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad, Mac — better | iPhone, iPad |
| Requires iOS | 17.0 | 17.0 |
| Further details — not scored | ||
| Size | 816 MB | 80 MB |
| Age rating | 9+ | 4+ |
| Developer | Alex Hastings | Sean Bowman |
Customer experience
ASTB Prep
CBDR
Bugs and requests
ASTB Prep
Reported bugs
2 issues- Mechanical comprehension test has 30 questions, not 20
- Terrain identification section has occasional screen color issues
Requested features
4 requests- Option to disable timer for terrain identification
- Ability to configure duration of correct answer display
- Add audio for UAV portion to simulate real test experience
- Include emergency scenario training for UAV
CBDR
Not enough reviews yet to summarise bugs or requests.
In-app purchases
ASTB Prep
- Joystick FunctionalityFree
- Full Access$39.99
CBDR
No in-app purchases









