# 737 CSFF — Cold Soaked Fuel Frost guide > 737 CSFF study guide for understanding cold soaked fuel frost scenarios. (iPhone/iPad app by Dan O'Leary.) - Source: https://appshunter.io/ios/app/737-csff/id1551516212 (this page in markdown: same URL + `.md`) - Developer: [Dan O'Leary](https://appshunter.io/developer/1177083778) - Category: Utilities, Education - Price: $2.99 - Rating: 5.00/5 from 2 App Store ratings - Age rating: 4+ - Requires: iOS 17.6 · 11 MB - Languages: English - Released: 2021-02-25 - Data updated: 2026-08-03 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/737-csff/id1551516212/reviews.md ## What is 737 CSFF? This app is a study guide and a visual representation to aid in the understanding around the many scenarios when Cold Soaked Fuel Frost (CSFF) is encountered on the wing of a 737. This app is not approved for use during flight operations. The CSFF guidance in this app is designed around a North American Airline Flight Handbook and reference to the Boeing FCOM. This app is not a substitute for company flight manuals, an FAA approved deicing program, Boeing FCOM guidance or good judgement. ## Key features - Visual representation of CSFF scenarios - Study guide for 737 wing frost - References North American Airline Flight Handbook - Includes Boeing FCOM guidance - Educational tool for pilots ## Chart rankings - #197 in Top Paid · Utilities (US App Store) ## Frequently asked questions about 737 CSFF ### What is 737 CSFF? 737 CSFF is a study guide and visual tool designed to help users understand Cold Soaked Fuel Frost (CSFF) scenarios encountered on the wings of a 737 aircraft. It references industry standards for educational purposes. ### Is 737 CSFF approved for flight operations? No, 737 CSFF is explicitly stated as not approved for use during flight operations. It is intended solely as a study guide and educational resource. ### What information sources does 737 CSFF use? The guidance within 737 CSFF is based on a North American Airline Flight Handbook and references the Boeing FCOM. It is not a replacement for official company flight manuals or regulatory guidance. ### What devices does 737 CSFF support? 737 CSFF is available on Apple Watch, iPhone, and iPad, offering flexibility for users across different Apple devices. ### How often is 737 CSFF updated? The latest version, 1.3.3, was updated on July 21, 2025. This indicates a commitment to keeping the app current with relevant information. ### What is the price of 737 CSFF? 737 CSFF is a paid application, available for $2.99. This one-time purchase grants access to its educational content. ### What is the user rating for 737 CSFF? 737 CSFF has received an excellent rating of 5.0 stars based on 2 user reviews, suggesting high user satisfaction with its content and utility. ### Does 737 CSFF have ads? No, 737 CSFF does not contain advertisements. Users can access the study guide without interruptions from in-app ads. ## Version history (last 5 releases) ### 1.3.3 — 2025-07-21 Updated image assets. ### 1.3.2 — 2024-11-12 Selecting whether or not there is frost on the upper surface of the wing is now a button, instead of a two-position picker. Emphasizing that condition better and keeps the interaction of the app consistent throughout. ### 1.3.1 — 2024-06-29 Added support for larger text sizes. ### 1.3 — 2023-10-01 This update removes the expression "Secondary Ice Inspection" and replaces it with "Ice Check". The app has also been updated for compatibility with iOS and iPadOS 17. ### 1.2 — 2023-03-07 watchOS Fixed incorrect wording regarding precipitation from "Visible Moisture" to "No Visible Moisture". Added (3mm) depth for under wing frost to better adhere to metric values. Minimum deployment target is now watchOS 9.0 iOS Added image of Fuel Stick 4 for greater awareness of where under wing frost may affect upper wing frost. Thank you Thomas. Added metric value of 3mm at header caution note. ## Apps similar to 737 CSFF | App | Rating | Price | Category | | --- | --- | --- | --- | | [SSI Steel Design](https://appshunter.io/ios/app/ssi-steel-design/id1474838160) | 3.0 (1) | Free | Utilities | | [JEDA Live 職達](https://appshunter.io/ios/app/jeda-live/id1476523220) | — | Free | Utilities | | [Rule of Three Calculator](https://appshunter.io/ios/app/rule-of-three-calculator/id1185318300) | 2.3 (4) | Free | Utilities | | [小灵龙App](https://appshunter.io/ios/app/app/id1221738240) | 1.0 (12) | Free | Utilities | | [TLF Events Tamil](https://appshunter.io/ios/app/tlf-events-tamil/id1481109080) | — | Free | Utilities | | [レコーダー - スピークバディ パーソナルコーチング](https://appshunter.io/ios/app/id1469874020) | — | Free | Utilities | ## More apps by Dan O'Leary - [Run Roster](https://appshunter.io/ios/app/run-roster/id1496557315) - [Tyre Myles](https://appshunter.io/ios/app/tyre-myles/id1595711689) - [FBO Fuel Management: ProFuelr](https://appshunter.io/ios/app/fbo-fuel-management-profuelr/id6446459695) - [Crochet Critters](https://appshunter.io/ios/app/crochet-critters/id6478188972) - [The Midst](https://appshunter.io/ios/app/the-midst/id6593661633) All apps by Dan O'Leary: https://appshunter.io/developer/1177083778 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-03.*