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Aircraft performance

STC ST09992SC

FAA DRS lists ST09992SC as Current · Issued, held by Underwood - Instrument Services, Inc., for Learjet 24, Learjet 24A, and Learjet 24B, and 8 more aircraft configurations. Recorded change: Replace existing production installed S-225 series Mach Airspeed Indicators with REVUE THOMMEN AG Type 5C18.22.65K.00.0 Mach Airspeed Indicators. Snapshot dated June 30, 2026.

FAA-listed holder
Underwood - Instrument Services, Inc.
Aircraft configurations
11
FAA revision date
FAA status
Current · Issued

Recorded modification

What the FAA record covers

Replace existing production installed S-225 series Mach Airspeed Indicators with REVUE THOMMEN AG Type 5C18.22.65K.00.0 Mach Airspeed Indicators.

ST09992SC identifies the approval, recorded holder, named aircraft, and modification scope. It does not confirm kit availability, serial-number effectivity, data rights, price, or installation authority.

Applicability

Aircraft named in FAA DRS

Named aircraft: Learjet 24, Learjet 24A, and Learjet 24B, and 8 more aircraft configurations. Confirm the approved model list, serial effectivity, configuration, and certificate revision.

Learjet 24A10CELearjet 24AA10CELearjet 24BA10CELearjet 24DA10CELearjet 24FA10CELearjet 25A10CELearjet 25AA10CELearjet 25BA10CELearjet 25CA10CELearjet 25DA10CELearjet 25FA10CE

Buyer checks

Confirm before sourcing

  1. 01Does it cover the exact Learjet 24 and Learjet 24A, and 9 more aircraft configurations model, serial range, and configuration?
  2. 02Which limits, loading assumptions, performance data, and supplements apply?
  3. 03Who can legally supply the design data, kit, instructions, and ICAs?
  4. 04What parts, labor, conformity, and return-to-service work are excluded?

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