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ETTC'2003 - SEE

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CLASSICAL FLIGHT TEST INSTALLATIONS<br />

Over 20 years of Flight Tests have led to complex architectures for Flight Test Installations, mainly<br />

built by adding bricks to existing chains. When technology raised some barriers, the safe and easy<br />

way has often been to create new acquisition & recording chains. This has been the case with the<br />

duplication of the basic FTI (only Basic FTI is shown in Fig. 1) to perform FANS Flight Tests, or with<br />

the Wide Band specific chain for analog measurements up to 20 kHz.<br />

« CRASH » PARAMETERS<br />

ANALOG<br />

MEASUREMENTS<br />

DC to 20 Khz<br />

MEASUREMENTS<br />

DC to 100Hz<br />

buses<br />

discretes<br />

FTI n° 1<br />

FTI n° 2<br />

CONDITIONING<br />

UNIT<br />

PARAMETERS ’S COPY<br />

CONDITIONING<br />

UNITS<br />

PARAMETERS ’S COPY<br />

DIGITAL<br />

ACQUISITION UNITS<br />

PCM1<br />

DIGITAL<br />

ACQUISITION UNITS<br />

PCM2<br />

DIGITAL<br />

ACQUISITION UNITS<br />

PCM3<br />

DIGITAL<br />

ACQUISITION UNITS<br />

PCM4<br />

DIGITAL<br />

ACQUISITION UNITS<br />

PCM4<br />

PCM2<br />

PCM3<br />

DIGITAL<br />

ACQUISITION<br />

UNIT<br />

CENTRAL<br />

CONTROL<br />

UNIT<br />

SWITCHING<br />

UNITS<br />

PCM1<br />

PCM4<br />

4 PCM<br />

COCKPIT<br />

VOICE<br />

DIGITAL<br />

RECORDER 1<br />

PCM1<br />

PCM2<br />

PCM3<br />

PCM4<br />

DIGITAL<br />

RECORDER 2<br />

CRASH<br />

RECORDER<br />

SIGNAL<br />

PROCESSING<br />

UNIT<br />

2 DIGITAL<br />

RECORDER<br />

MADAM<br />

CENTRAL<br />

UNIT<br />

Figure 1 – A340-500/600 Basic FTI Architecture<br />

Various other acquisition chains have seen the light for very specific needs (audio, video, small FTIs…)<br />

and are also totally independent one from the others.<br />

The real limitation of these architectures, apart of the limited throughput, lies on the noninterconnectivity<br />

of the various equipments. Since data format is not homogeneous, and systems IO<br />

are only Half Duplex and mostly point-to-point connections, it was not possible to merge or exchange<br />

data between FTI systems on classical architecture.<br />

In classical FTI architecture, acquisition systems provide an output link coming from Telemetry world<br />

(Pulse Code Modulation), which principle is a cyclic transmission of all the aircraft parameters at a<br />

cadence around 800 kbit/s.<br />

MADAM<br />

DISPLAY<br />

MADAM KEYBOARD<br />

MADAM PRINTER<br />

One PCM is usually built with the following characteristics :<br />

12 bits per Word<br />

128 Words per Minor Cycle<br />

256 Minor Cycles per Major Cycle<br />

2 Major Cycles per second<br />

ANALOG<br />

RECORDER 1<br />

ANALOG<br />

RECORDER 2<br />

ANALOG<br />

RECORDER 3<br />

SLOW PCM6<br />

PCM 5<br />

SYNCHRO<br />

CUB<br />

PROCESSOR<br />

UNIT 1<br />

CUB<br />

DISPLAY<br />

UNIT 1<br />

CUB 1<br />

KEYBOARD<br />

TO TELEMETRY<br />

GROUND STATION<br />

ANTENNAS<br />

TELEMETRY<br />

TRANSMITTER<br />

FLIGHT<br />

CONDITION<br />

PROCESSOR<br />

UNIT<br />

FLIGHT<br />

CONDITION<br />

DISPLAY UNIT<br />

DGPS RAW DATA<br />

and PCM5<br />

RECORDER<br />

The standard bit rate of PCM messages used on AIRBUS FTIs is then 786,432 kbit/s.<br />

LD<br />

CUB<br />

PROCESSOR<br />

UNIT 2<br />

CUB<br />

DISPLAY<br />

UNIT 2<br />

CUB 2<br />

KEYBOARD<br />

FLIGHT TEST ENGINEER STATION<br />

GPS<br />

RECEIVER<br />

GPS CLOCK<br />

GPS TIME<br />

TIME<br />

BASE<br />

GENERATOR<br />

GPS<br />

ANTENNA<br />

PLOTTING<br />

PROCESSOR<br />

UNIT<br />

TRAJECTOGRAPHY<br />

GPS DIFFERENTIEL<br />

UNIT<br />

GMT<br />

IRIG-B<br />

TO<br />

EQUIPEMENTS<br />

GRAPHIC<br />

RECORDERS<br />

HARD<br />

COPIERS

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