{"data":{"id":"us/14-cfr-appendix-e-to-part-135","jurisdiction":"us","citation":"14 CFR Appendix E to Part 135","heading":"Appendix E to Part 135—Helicopter Flight Recorder Specifications","body":"Parameters Range Accuracy sensor input to DFDR readout Sampling interval (per second) Resolution 2 read out\nTime (GMT) 24 Hrs ±0.125% Per Hour 0.25 (1 per 4 seconds) 1 sec\nAltitude −1,000 ft to max certificated altitude of aircraft ±100 to ±700 ft (See Table 1, TSO-C51a) 1 5′ to 30′.\nAirspeed As the installed measuring system ±3% 1 1 kt\nHeading 360° ±2° 1 0.5°.\nNormal Acceleration (Vertical) −3g to + 6g ±1% of max range excluding datum error of ±5% 8 0.01g\nPitch Attitude ±75° ±2° 2 0.5°\nRoll Attitude ±180° ±2° 2 0.5°.\nRadio Transmitter Keying On-Off (Discrete) 1 0.25 sec\nPower in Each Engine: Free Power Turbine Speed and Engine Torque 0-130% (power Turbine Speed) Full range (Torque) ±2% 1 speed 1 torque (per engine) 0.2% 1 to 0.4% 1\nMain Rotor Speed 0-130% ±2% 2 0.3% 1\nAltitude Rate ±6,000 ft/min As installed 2 0.2% 1\nPilot Input—Primary Controls (Collective, Longitudinal Cyclic, Lateral Cyclic, Pedal) 3 Full range ±3% 2 0.5% 1\nFlight Control Hydraulic Pressure Low Discrete, each circuit 1\nFlight Control Hydraulic Pressure Selector Switch Position, 1st and 2nd stage Discrete 1\nAFCS Mode and Engagement Status Discrete (5 bits necessary) 1\nStability Augmentation System Engage Discrete 1\nSAS Fault Status Discrete 0.25\nMain Gearbox Temperature Low As installed As installed 0.25 0.5% 1\nMain Gearbox Temperature High As installed As installed 0.5 0.5% 1\nControllable Stabilator Position Full Range ±3% 2 0.4% 1.\nLongitudinal Acceleration ±1g ±1.5% max range excluding datum error of ±5% 4 0.01g.\nLateral Acceleration ±1g ±1.5% max range excluding datum of ±5% 4 0.01g.\nMaster Warning Discrete 1\nNav 1 and 2 Frequency Selection Full range As installed 0.25\nOutside Air Temperature −50 °C to + 90 °C ±2° c 0.5 0.3° c\n1 Per cent of full range.\n2 This column applies to aircraft manufactured after October 11, 1991.\n3 For all aircraft manufactured on or after December 6, 2010, the sampling interval per second is 4.","path":["Title 14—Aeronautics and Space","CHAPTER I—FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION","SUBCHAPTER G—AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS","PART 135—OPERATING REQUIREMENTS: COMMUTER AND ON DEMAND OPERATIONS AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-14.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:20Z","sha256":"e0eb6475befdc305e06ab49d6663aa145ffe898b5a9d259f41c1c54c5e86dd6a","source_id":"us-cfr","stale":true,"prev":"us/14-cfr-appendix-d-to-part-135","next":"us/14-cfr-appendix-f-to-part-135"},"notice":"GroundRules: Original legal text. Not legal advice."}