The Clearspar blog
Notes on building a Part 135 charter quoting + compliance tool — the hard calls, the tradeoffs, and the things we got wrong and fixed.
Why no LLM touches a dollar in our quotes
A language model reads the email. Plain, testable arithmetic does the money and the compliance — so anyone can recompute the number by hand.
We made compliance the moat, not speed
Anyone can quote fast. A correct, defensible compliance gate a Director of Operations will sign off on is the hard part — so that is the product.
Designing software that says no
Most software is built to say yes. Compliance software has to surface UNABLE — with the citation and a legal alternative.
The integration is a forwarding address
Operators will not rip out their stack for a startup. So the whole integration is forwarding an email.
The night prod went down: a Prisma foot-gun
A unique constraint crash-looped a deploy into an overnight outage. The fix was resilience — not the dangerous flag everyone reaches for.
Why we don’t touch the charter payment
It is tempting to take a cut of a six-figure flight. Moving that money is a trap — and a tell. Here is why we stay out.
Audit-ready by default
The compliance log you keep anyway becomes a report a DO — or an underwriter — can use. Honestly framed, no premium promises.
A data flywheel without breaking trust
Every quote teaches us the real market rate on a lane. Capturing that without betraying the operators who created it.
Gray charter: the risk buyers don’t know they have
Flying commercially under Part 91 to dodge 135 is the most expensive mistake in charter — and an educated market is our market.
Pricing a trust product
Per-seat punishes a dispatch desk. Cheap signals “utility.” How we landed on custom, demo-led, unlimited-user pricing.
14 CFR 135.267: what the duty time rules actually say
A plain-language breakdown of the Part 135 duty and rest limits — the 14-hour duty period, the 10-hour rest minimum, cumulative caps, and what “reduced rest” really means.
Charter dispatch software: what to ask before you buy
Most charter dispatch tools handle scheduling. The legal gate is where the real risk lives. Questions that separate compliance tools from calendar apps.
Part 135 crew rest: the 8-hour floor, the 10-hour minimum, and when you can reduce
The FAA gives Part 135 operators one reduced-rest provision per 135.267(d). Here is exactly when you can use it, what the floor is, and what the logbook must show.