Download the PDF consolidation of Part 135 [PDF 432 KB]
Cockpit voice recorders must—
(1) meet the requirements of the TSO C84 series or the TSO C123 series; and
(2) be fitted with an underwater locating device that meets the requirements of the TSO C121 series; and
(3) have a minimum capacity of 30 minutes continuous recording time before any erasure.
Flight data recorders must—
(1) meet the requirements of the TSO C124 series; and
(2) be fitted with an underwater locating device that meets the requirements of the TSO C121 series; and
(3) be of a non-ejectable type and capable of recording and storing 8 hours of data in a digital form; and
(4) except as provided in an MEL, record the parameters as detailed in—
(i) Figure 1 below; and
as applicable, Table 1 and Table 2 below.
When reading the parameter specifications from Table 2 the corresponding shaded specification should be chosen for each parameter. This table refers to the FDR requirements of rule 135.369.
Table 1 PDF version [PDF 428 KB]
| (A) | (B) | |
|---|---|---|
| Parameter | 23 Parameter Helicopter | 25 Parameter Helicopter |
| 1 | Time | Time |
| 2 | Airspeed | Altitude |
| 3 | Altitude | Airspeed |
| 4 | Heading | Heading |
| 5 | Vertical acceleration | Vertical acceleration |
| 6 | Longitudinal acceleration | Pitch attitude |
| 7 | Pitch attitude | Roll attitude |
| 8 | Roll attitude | Radio transmitter keying |
| 9 | Altitude rate | Power in each engine: Free power turbine speed and engine torque |
| 10 | Main rotor speed | Main rotor speed |
| 11 | Free or power turbine for each engine | Altitude rate |
| 12 | Engine torque for each engine | Pilot input - primary controls |
| 13 | Primary hydraulic pressure | Flight control hydraulic pressure low |
| 14 | Secondary hydraulic pressure (if available) | Flight control hydraulic pressure selector switch position, 1st and 2nd stage |
| 15 | Radio transmitter keying | AFCS mode and engagement status |
| 16 | Autopilot engaged | SAS status - engaged |
| 17 | SAS status - engaged | SAS fault status |
| 18 | SAS fault status | Main gearbox temperature low |
| 19 | Collective | Main gearbox temperature high |
| 20 | Pedal position | Controllable stabilator position |
| 21 | Lateral cyclic | Longitudinal position |
| 22 | Longitudinal cyclic | Lateral acceleration |
| 23 | Controllable stabilator position | Master warning |
| 24 | Nav 1 and Nav 2 frequency selection | |
| 25 | Nav 1 and Nav 2 frequency selection |
This table refers to the FDR requirements of rule 135.369.
Table 2 PDF version [PDF 468 KB]
| Parameters | Range | Installed system minimum accuracy (to recovered data) 1 | Sampling interval (per second) | Resolution read out 2 |
|---|---|---|---|---|
| Relative time (from recorded on prior to take-off) | 25 hr minimum 24 hours |
±0.125% per hour | 1 0.25 |
1 sec |
| Indicated airspeed | Vmin to VD (KIAS) (minimum airspeed signal attainable with installed pitot/static system) As the installed measuring system |
±5% or ±10 knots, whichever is greater ±3% |
1 | 1 kt. |
| Altitude | -1,000 ft to 20,000 ft pressure altitude -1,000 ft to max certificated altitude of aircraft |
±100 to ±700 ft (see Table 1, TSO C51-a) | 1 | 25 to 150 ft 5’ to 30’ |
| Magnetic heading | 360° | ±5° ±2° |
1 | 1° 0.5° |
| Vertical acceleration | -3 g to +6 g | ±0.2 g in addition to ±0.3 g maximum datum ±1% of max range excluding datum error of ±5% |
4 (or 1 per second where peaks, ref. to 1 g are recorded) 8 |
0.05 g 0.01g |
| Longitudinal acceleration | ±1.0 g | ±1.5% max. range excluding datum error of ±5% | 2 4 |
0.03 g 0.01g |
| Lateral Acceleration | ±1.0 g | ±1.5% max. range excluding datum error of ±5% | 4 | 0.01g |
| Pitch attitude | 100% of usable range ±75° |
±2° | 1 2 |
0.8° 0.5° |
| Roll attitude | ±60° or 100% of usable range, whichever is greater ±180° |
±2° | 1 2 |
0.8° 0.5° |
| Altitude rate | ±8,000 fpm ±6,000 fpm |
±10% Resolution 250 fpm below 12,000 ft indicated As installed |
1 2 |
250 fpm below 12,000 0.2% |
| Engine power each engine | ||||
| Main rotor speed | Maximum range 0-130% |
±5% ±2% |
1 2 |
1% of full range 0.3% of full range |
| Free or power turbine | Maximum range 0-130% (power Turbine Speed) |
+5% +2% |
1 (per engine) | 1% of full range 0.2% to 0.4% of full range |
| Engine torque | Maximum range | ±5% ±2% |
1 (per engine) | 1% of full range 0.2% to 0.4% of full range |
| Flight Control - Hydraulic Pressure | ||||
| Hydraulic Pressure Low | Discrete, each circuit | 1 | ||
| Hydraulic Pressure Selector Switch Position, 1st and 2nd Stage | Discrete | 1 | ||
| Primary (discrete) | High/low | 1 | ||
| Secondary - if applicable (discrete) | High/low | 1 | ||
| Avionics | ||||
| Radio transmitter keying (discrete) | On/off | 1 | ||
| Autopilot engaged (discrete) | Engaged or disengaged | 1 | ||
| AFCS Mode and Engagement | Discrete (5 bits necessary) | 1 | ||
| SAS status - engaged (discrete) | Engaged/disengaged | 1 | ||
| SAS fault status (discrete) | Fault/OK | 1 0.25 |
||
| Flight Controls | ||||
| Collective | Full range | ±3% | 2 | 1% of full range 0.5% of full range |
| Pedal position | Full range | ±3% | 2 | 1% of full range 0.5% of full range |
| Lateral cyclic | Full range | ±3% | 2 | 1% of full range 0.5% of full range |
| Longitudinal cyclic | Full range | ±3% | 2 | 1% of full range 0.5% of full range |
| Controllable stabilator position | Full range | ±3% | 2 | 1% of full range 0.4% of full range |
| Main Gearbox Temperature Low | As installed | As installed | 0.25 | 0.5% of full range |
| Main Gearbox Temperature High | As installed | As installed | 0.5 | 0.5% of full range |
| Master Warning | Discrete | 1 | ||
| Nav 1 and Nav 2 Frequency Selection | Full range | As installed | 0.25 | |
| Outside Air Temperature | -50°C to +90°C | ±2°C | 0.5 | 0.3°C |
1. When data sources are aircraft instruments (except altimeters) of acceptable quality to fly the aircraft the recording system excluding these sensors (but including all other characteristics of the recording system) must contribute no more than half of the values in this column.
2. This column applies to aircraft manufactured after October 11, 1991.
