Annexure-I

Complete Specification of Design and fabrication of In-situ simulation test kit for AHRS Memory
module programming.

Title of the invention

In-situ test kit for AHRS Memory module programming for Advanced Light Helicopter.

Field of invention

This invention is related to programming of AHRS Memory module.

Use of invention

This invention is used to decrease the TAT time of Helicopter servicing. With the test kit AHRS reprogramming can be performed on helicopter In-situ without removing.

Prior art

AHRS unit is integrated in Helicopter to provide attitudes, helicopter attitude rates, yaw rate, heading and accelerations to Automatic flight control system and IADS.Each AHRS has one magnetometer connected to it which is used to provide the heading information and each AHRS has both the air data units connected to it which provide baro-altitude,indiated air speed and true airspeed .During flight or ground run if the system is malfunctioning, AHRS unit will be removed along with Memory module and send for bench check/Functional check at LAB/OEM to know the serviceability of LRU. This test kit method is unique. There was no previous In-situ test kit method was available.

Draw backs of prior art

AHRS & Memory module is fitted at LH & RH side of Station #4 (On the floor
board).

Following are the sequence of operation to be followed to remove the AHRS &
Memory module unit from the Helicopter.

1. Troop seats both LH & RH side to be removed.

2. Disconnect the AHRS harness connected.

3. Remove the Memory module and AHRS mounting bolts along with the bonding braid connected.

4. Prepare the necessary snag sheet/PDO for the faulty unit and send to LAB/OEM for further testing.

5. At LRU Lab unit will be functionally tested for the reported snag.

6. After completion of shop level testing for the said snag, unit will be offered to Quality assurance for clearance.

7. If no deviation is observed LRU will be cleared as a IMFF case else If any deviation persists LRU need to be repaired at the concerned repair agency.

Comparison between prior art and present invention

As indicated above in Draw back section, AHRS & Memory module serviceability can only be known after completion of points mentioned from 1 to 7.With the In-situ test kit all the sequence mentioned from 1 to 7 can be avoided.

Aim of the invention

Aim of the invention is to decrease the TAT of Helicopter servicing by programming AHRS Memory module unit on the installed condition.

Summary of the present invention

AHRS unit is integrated in Helicopter to provide attitudes, helicopter attitude rates, yaw rate, heading and accelerations to Automatic flight control system and IADS.Each AHRS has one magnetometer connected to it which is used to provide the heading information and each AHRS has both the air data units connected to it which provide baro-altitude,indiated air speed and true airspeed .During flight or ground run if the system is malfunctioning, AHRS unit will be removed along with Memory module and send for bench check/Functional check at LAB/OEM to know the serviceability of LRU. This test kit method is unique. There was no previous In-situ test kit method was available.

After helicopter overhaul, during Air test schedule-1 AHRS calibration will be performed in air to ascertain attitudes, helicopter attitude rates, yaw rate, heading and accelerations. Using AHRS calibrator instrument AHRS calibration will be performed in different air profile/regimes. A caution indicator is installed on calibrator instrument which provides visual warning to pilot during performing flight.

During flight if the calibration fails, it will be recorded on calibration equipment as a caution. Accordingly pilot will register the snag in the concerned helicopter flight logbook. Ground engineering crew as per the snag recorded by the pilot will take the corrective action. At this instant serviceability of the AHRS unit along with memory module has to be checked.

By using this in-situ test kit reprogramming can be performed without disconnecting AHRS unit and memory module from the helicopter.

10. Statement of invention

This invented method is highly useful for production, Repair and overhaul divisions of helicopter industry, where Snag can be rectified in In-situ, fastest time, which will avoid the repeated removal and installation of the LRU thus improving the efficiency of the LRU and reduction in TAT for acceptance of the helicopter.

11. Detailed description of invention
a) AHRS unit is integrated in Helicopter to provide attitudes, helicopter attitude rates, yaw rate, heading and accelerations to Automatic flight control system and IADS. Each AHRS has one magnetometer connected to it which is used to provide the heading information and each AHRS has both the air data units connected to it which provide baro-altitude, indicated air speed and true airspeed.

b) AHRS is a single LRU mounted on the helicopter with harness connected from Station # 4 and provides output information to cockpit.

c) In the event of AHRS Memory module programming following sequence of technical activities will be carried out:

1. Harness from station #4 (Sliding door) to station l(Nose cabin) continuity to be checked.

2. Junction modules connected in between station #4 to station #1 to be checked for any loose contact or damage.

3. If the continuity of the harness is found satisfactory then meggar check to be done for measuring the insulation of the cables.

4. From station 1 to inside cockpit, connected harness continuity and meggar to be carried to know the serviceability of the harness.

5. If the steps from point.1 to point.4 are satisfactory then AHRS Memory module programming will be carried out as indicated below:

(i)Connect function 28 v DC input voltage.

(ii)Remove AHRS unit from helicopter.

(iii)Collect new memory module from stores.

(iv) Install new memory module on AHRS.

(v) Connect AHRS to programming loom.

(vi) Connect other end of the programming loom to serial port of computer.

(vii)Load software on the programming computer,

(viii) Power on 28 v dc power supply,

(ix) Collect the data to be fed in the memory module,

(x) According to data start programming memory module, (xi) Disconnect AHRS and memory module, (xii) Disconnect serial port connection and power connections, (xiii) Install AHRS and memory module in the helicopter.

7. With the AHRS Memory module programming in-situ kit point.i to point.xii can be eliminated and serviceability of the AHRS and memory module can be confirmed without removal of unit from the helicopter. 8. In-situ test kit consists of following features:
(a) In built 28 v DC power supply tapping.
(b)Easy serial port connection cable.
(c)AHRS D-connectors compatible versions.
(d)Easy serial port connector locking.
(e) Easy to carry.
(f) Saves maintenance time for snag rectification.

Annexure-II

We Claim

1. The design and fabrication of In-situ simulation test kit for AHRS Memory module programming unit and its methodology gives a conformation of serviceability/functionality of AHRS unit and Memory module is claim-1

2. The design and its methodology is to test Memory module data in static condition is claim-2.

3. The design and methodology of use of 28 v inbuilt power supply is claim-3.

4. The design and methodology of and easy accessibility serial port is claim-4.

5. The design and methodology of providing D-type connector to avoiding short circuit is claim-