Definition
An FAA Technical Standard Order that sets the minimum performance standards for airborne supplemental navigation sensors using GPS augmented by Satellite-Based Augmentation System (SBAS) signals. Equipment certified to TSO-C196 (or its successors) may be used as a supplemental means of navigation under IFR, and is one of the authorizations that allows a pilot to plan an instrument flight with destination weather forecasts below standard alternate minima while still using a GPS-based approach at the alternate, subject to current operational rules.
Plain English
It is the FAA approval standard for a type of GPS receiver that can use satellite-based correction signals to improve accuracy. If your GPS is approved to this standard, the FAA treats it as reliable enough for certain IFR planning rules involving alternate airports.
Context Anchor
You may see TSO-C196 in the aircraft flight manual supplement, GPS equipment approval paperwork, or FAA guidance about IFR alternate airport requirements.
Derivation
TSO stands for Technical Standard Order, which is the FAA's way of saying 'here is the minimum spec a piece of equipment must meet to be approved.' The number (C196) is just the catalog identifier for this particular standard. Knowing it is a TSO tells you it is an equipment-approval document, not a procedure or regulation.
Why Pilots Care
Confirms whether installed GPS equipment satisfies regulatory requirements for filing and using IFR alternates.
Intuition Check
Do not read TSO-C196 as just a serial number or a GPS model name. It is an FAA approval standard that affects how the equipment may be used.
Example Sentence 1
Because the aircraft's GPS is certified to TSO-C196, the pilot was able to file an alternate that only had a GPS approach available.
Example Sentence 2
Before departure the pilot verified that the navigation equipment complied with TSO-C196 as required for the planned IFR flight.