GM1 NCC.GEN.145(b) Handling of flight recorder recordings: preservation, production, protection and use

INSPECTION OF THE FLIGHT RECORDERS’ RECORDINGS FOR ENSURING SERVICEABILITY

(a)     The inspection of the recorded flight parameters usually consists of the following:

(1)     Making a copy of the complete recording file.

(2)     Converting the recording to parameters expressed in engineering units in accordance with the documentation required to be held.

(3)     Examining a whole flight in engineering units to evaluate the validity of all mandatory parameters – this could reveal defects or noise in the measuring and processing chains and indicate necessary maintenance actions. The following should be considered:

(i)      when applicable, each parameter should be expressed in engineering units and checked for different values of its operational range – for this purpose, some parameters may need to be inspected at different flight phases; and

(ii)     (only applicable to an FDR) if the parameter is delivered by a digital data bus and the same data are utilised for the operation of the aircraft, then a reasonableness check may be sufficient; otherwise a correlation check may need to be performed:

(A)     a reasonableness check is understood in this context as a subjective, qualitative evaluation, requiring technical judgement, of the recordings from a complete flight; and

(B)     a correlation check is understood in this context as the process of comparing data recorded by the flight data recorder against the corresponding data derived from flight instruments, indicators or the expected values obtained during specified portion(s) of a flight profile or during ground checks that are conducted for that purpose.

(4)     Retaining the most recent copy of the complete recording file and the corresponding recording inspection report that includes references to the documentation required to be held.

(b)     When performing the inspection of an audio recording from a flight recorder, precautions need to be taken to comply with NCC.GEN.145(f)(1a). The inspection of the audio recording usually consists of:

(1)     checking that the flight recorder operates correctly for the nominal duration of the recording;

(2)     examining samples of in-flight audio recording from the flight recorder for evidence that the signal is acceptable on each channel and in all phases of flight; and

(3)     preparing and retaining an inspection report.

(c)      The inspection of the DLR recording usually consists of:

(1)      Checking the consistency of the data link recording with other recordings for example, during a designated flight, the flight crew speaks out a few data link messages sent and received. After the flight, the data link recording and the CVR recording are compared for consistency.

(2)      Retaining the most recent copy of the complete recording and the corresponding inspection report.

(d)     When inspecting images recorded by a flight recorder, precautions need to be taken to comply with NCC.GEN.145(f)(3a). The inspection of such images usually consists of the following:

(1)     checking that the flight recorder operates correctly for the nominal duration of the recording;

(2)     examining samples of images recorded in different flight phases for evidence that the images of each camera are of acceptable quality; and

(3)     preparing and retaining an inspection report.