AMC 29.1459 Flight Data Recorders

This AMC provides further guidance and acceptable means of compliance to supplement FAA AC 29-2C § AC 29.1459. § 29.1459, to meet EASA's interpretation of CS 29.1459. As such, it should be used in conjunction with the FAA AC.

1. General

The installation of a recorder with an ETSO authorisation against ETSO-C124 (or equivalent standard accepted by EASA) satisfies the approval requirement in CS 29.1459(a).

In showing compliance with CS 29.1459, the applicant should take into account EUROCAE Document ED-112A ‘MOPS for Crash-Protected Airborne Recorder Systems’ or a later revision.

’FDR system’ designates the flight data recorder (FDR) and its dedicated equipment. It may include the following items as appropriate to the aircraft:

a. Equipment necessary to:

i. acquire and process analogue and digital sensor signals;

ii. store the recorded data in a crash-survivable recording medium; and

iii. when necessary, support dedicated sensors.

b. Digital data buses and/or networks providing communications between the elements of the system.

2. Automatic means to stop the recording after a crash impact

Refer to the Section of AMC 29.1457 titled ‘Automatic means to stop the recording after a crash impact’.

3. Combination recorder

Refer to the Section of AMC 29.1457 titled ‘Combination recorder’.

4. Instructions for continued airworthiness (ICAs)

When developing the ICAs for the FDR system, required by CS 29.1529 and its Appendix A, the applicant should address all failures that may affect the correct functioning of the FDR system or the quality of the recorded data.

Examples of failures (indicative and non-exhaustive list):

— The loss of the recording function or of the acquisition function of the FDR.

Any parameter (required by CS 29.1459(a)(1) or by the applicable air operations regulations) is missing or is not correctly recorded.

— The failure of a sensor dedicated to the FDR system.

— The failure of a means to facilitate the finding of the FDR recording medium after an accident (e.g. an underwater locating device or an emergency locator transmitter attached to the recorder).

— The failure of the start-and-stop function.

— The failure of a means to detect a crash impact (for the purpose of stopping the recording after a crash impact, or for the purpose of deploying the recorder if it is deployable).

In addition, the ICAs should include the following items, unless the applicant shows that this is not applicable:

— Calibration checks of the parameters from sensors dedicated to the FDR to verify the accuracy of these parameters; and

— FDR decoding documentation:

i. Definitions

FDR decoding documentation: a document that presents the information necessary to retrieve the raw binary data of an FDR data file and convert it into engineering units and textual interpretations.

Fixed frame recording format: a recording format organised in frames and subframes of a fixed length and that are recorded chronologically. ARINC specifications 573 and 717 provide an example of a fixed frame recording format.

Variable frame recording format: a recording format based on recording frames which are individually identified and time stamped, so that their order in the recording file is not important. ARINC specification 767 provides an example of variable frame recording format.

ii. Content of the FDR decoding documentation

The FDR decoding documentation should at least contain information on the following:

— the aircraft make and model;

— the document modification date and time;

— in the case of a fixed-frame recording format:

— the sync pattern sequence;

— the number of bits per word, of words per subframe and of subframes per frame; and

— the time duration of a subframe;

— in the case of a variable-frame recording format, the list of frames, and for each frame:

— its identification;

— information on whether the frame is scheduled or event triggered;

— the recording rate (for a scheduled frame);

— the frame event condition (for an event-triggered frame); and

— the list of parameters, by order of recording;

— for every parameter:

— the identification: name (and mnemonic code or other identification if applicable);

— the sign convention and the units of the converted values (if applicable);

— the location of each parameter component in the data frame;

— instructions and equations to assemble the parameter components and convert the raw binary values into engineering units (if applicable); and

— the conversion to text or the discrete decipher logic (if applicable).

iii. Format of the FDR decoding documentation

The FDR decoding documentation should:

— be provided in an electronic format;

— contain all the information described in paragraph (ii) above; and

— comply with the standard of ARINC Specification 647A or a later equivalent industry standard.

[Amdt 29/7]

[Amdt 29/9]