Complete Specification of Weight off Wheel (WOW) simulation box to simulate WOW without jacking up the Aircraft

S.No. Content Sheet No
1 Title of the invention 3
2 Field of invention 3
3 Use of invention 3
4 Prior art 3
5 Draw backs of prior art 3
6 Comparison between prior art and present invention
7 Aim of the invention 4
8 Summary of the present invention 4
9 Drawings & worked examples 5

1. Title of the invention
Weight off Wheel (WOW) simulation box to simulate WOW without jacking up the Aircraft

2. Field of invention
It is an electrical engineering design used for aircraft Integration.

3. Use of invention
This invention finds its applicability in aircrafts for testing the aircraft system on the ground in the 'weight off wheels' condition.

4. Prior art
The current practice is to jack up the aircraft to create weight off wheel condition for testing the aircraft systems in weight off wheel condition, i.e. flight mode.

5. Draw backs of prior art

i. The Aircraft has to be jacked up for creating weight off wheel condition which takes 2 to 3 hours.

ii. Jacking up the aircraft requires lot of infrastructure and manpower.

iii. In Jackup condition, any test with weight on wheel condition, i.e. ground mode checks can not be done.

iv. Removal of the jack also needs lot of time, infrastructure and manpower.

6. Comparison between prior art and present invention

Prior invention I Present invention

The Aircraft has to be jacked up for No need to jack up the aircraft for creating weight off wheel condition creating weight off wheel condition.

Creating weight off wheel condition Creating weight off wheel condition takes 2 to 3 hours. takes 5 to 10 minutes Jacking up the aircraft requires lot This invention requires the WOW of infrastructure and manpower. simulation box and one person only.

In Jackup condition, any test with Weight off wheel or weight on wheel weight on wheel condition can not test can be done at any time by be done. selecting the switch on the WOW

Simulation box accordingly.

7. Aim of the invention
Aim of the invention is to eliminate the draw backs in the present practices of putting the aircraft on the jack for creating weight off wheel condition.

8. Summary of the present invention
In aircraft, weight off wheel (WOW) signal is being used by many systems viz. Flight Control System, Mission Computer, Armament System, Brake System, etc. In order to carry out checks on ground of any of the system above, it became necessary to jack up the Aircraft. Jacking up the aircraft required 5-6 hours of work and was quite cumbersome. WOW Simulation Box has been fabricated to avoid jacking up of the aircraft.

On the aircraft, there are micro-switches for sensing the Weight on Wheel status of nose, LH and RH landing gears respectively. For each of these micro-switches there is a connector through which the micro-switch is integrated to the aircraft wiring.

The WOW Simulation box comprises of three switches and four connectors. The three switches are designated as nose, LH and RH respectively. Each switch has two positions Air and Ground.

There is a harness linking the simulation box and the aircraft. One end of the harness is connected to the simulation box. The other end of the harness has 3 connectors to mate with the aircraft weight on wheel connectors. A provision has been made in the box to store the link harness when not in use.

Using the simulation box, either one WOW or all the three WOWs can be simulated. To simulate Weight off Wheel condition on ground, the aircraft connectors are demated from the aircraft micro switches and mated with the WOW box link harness connectors. Depending on the requirement, the particular WOW (Nose, LH or RH) can be simulated for Air (Weight Off Wheel) or Ground (Weight on Wheel Condition) by selecting the switch on the simulation box.

Using this box, performance of all systems on aircraft which need "Weight off Wheel" condition, can be tested without actually having to jack up the aircraft. Routine Functional Tests (RFT) which needs weight off wheel signal can be carried out using this simulation box. This WOW simulation box has also been used for simulation of "In-flight Engine Relight" on ground. This is a significant simulation test done on the ground to evaluate the performance of aircraft systems during In-flight restarting.

Claims

1. A single and simple Weight Off Wheel Simulation Box replaces the complicated practice of putting the aircraft on jack for testing the aircraft systems underweight off wheel condition.

2. With simple Weight Off Wheel Simulation Box it is easily possible to change from Weight off wheel condition to weight on wheel condition and vice versa by just selecting the switches on the Weight Off Wheel simulation Box accordingly.