1. Title of the invention
Application process of poly sulphide sealant to avoid water ingress and jettisoning testing process on emergency exit door of helicopter.
2. Field of invention
It is an innovative manufacturing process for application of poly sulphide sealant on the emergency exit door to avoid the water ingress during flight or waterproofing of the sub assembly and to test its capability of jettisoning during emergency.
3. Introduction about Emergency Exit Door:
Emergency exit door:
Emergency exit door is a movable door/ window or a panel providing an unobstructed opening suitable for emergency evacuation of helicopter at emergency conditions.

a) Two main elements of emergency exit door assembly :
• The locking mechanism which locks the emergency exit door with the sliding door assembly and the helicopter structure via 6 locking pins. These pins can be operated by handles simultaneously from in and outside of the helicopter at the time of emergency situation.
• The poly sulphide sealant is being applied at the joggle area of the door to cover the gap between emergency exit door and sliding door. It avoids the water ingress during flight and holds the door up to an extant of pushing. Due to this even if the emergency door will be operated by mistake during flight it will not fall immediately.

b) Raw Materials used:
■ Poly sulphide sealant.
■ Foam rubber.
■ Pressure sensitive tape.
■ Masking tape
c) Tools and Facilities used:
■ Sealant application gun.
■ Load measuring gauge.
■ Mounting fixture to hold the door similarly as on helicopter.

4. Use of invention
This invented process can be used to seal the emergency exit doors of helicopters and to test it for proper jettisoning as per the standard FAR-29 at the time of emergency evacuation of the helicopter. The same technique can also be used for other vehicles also which have a provision of emergency exit door.
5. Prior art
Patents referred: The Details of the patents referred are given in the table below.
Emergency door:
The present invention relates to the technical field of emergency exit doors, for example in aircrafts, trains, boats or other vehicles. The invention concerns more specifically emergency jettison panels or Window panes in aircrafts, such as helicopters, which are not equipped with pressurized cabin. After an accident or a crash of a helicopter or another aircraft, it can be necessary for passengers to leave quickly their cabin, while the normal exit door is blocked. The passengers may also be injured and a quick access in the cabin must be possible for any rescue team. It is the reason why especially helicopters, are equipped with emergency jettisoning system.

Main constrains of emergency exit window assembly:
• The assembly should be easy to operate with a least amount of load so that a passenger in distress can evacuate from the helicopter in emergency situations or the help and rescue team can open the door and come in for rescue.
• It should be leak proof assembly so that the water ingress can be avoided in flight or on ground in the rain or bad weather condition.
• The requirement however it needs to be an easy to operate door but at the same time it should be attached to the structure until not operated.
• Even during flight if the operating mechanism of emergency exit door somehow gets
opened. It should not fall down due to vibrations.
Jettisoning process:
The locking mechanism has to be constructed with two handles which can be operated both from in and the outside. By operating the handle the locking pins get disengage and the door falls down thus it make a way for evacuation or entrance for the rescue team.
6. Draw backs of prior art
The following are the drawbacks:
• Few ejection systems use pyrotechnic means like gases for the purpose which is an expensive and difficult to handle system.
• Few systems use dry seal which is less efficient in waterproofing specially on irregular surfaces.
• Dry seals generally get hardened so these seals are more vulnerable to wear and tear which in turn again increases the risk of leakage.
• In general the dry seals will not provide additional strength to hold the door if the locking will get open by mistake.

• The installation process of the inflatable seal is also difficult and tricky which needs expertise and experience in such installations.
• Few prior arts are suitable only for small doors as it becomes more bulky and difficult to install for larger size of exit doors.
• It requires special tools and special structural features to accommodate the dry seal, which makes the system more complicated.
• There were no specific criteria about the applicable load to perform jettisoning operation and the limits of the load to be applied.
• There was not any specific procedure define to perform jettison testing which was causing variation in the results.
7. Comparison between prior art and present invention
The new invention in the sealant application and jettisoning testing gives following advantages over the prior arts.
• It is a very simple method of sealing the emergency exit window.
• It uses liquid poly sulphide sealant which after curing gets converts into solid rubber beading.
• The liquid sealant flows in the gaps between the emergency exit door and the structure thus provides a watertight sealing (fig.5).

• The material properties of the sealant are as following.
• The appropriate masking of the emergency exit door and the sliding door provides a controlled glue line thickness which in turn gives the optimum strength to the sealant (fig- 6).
• It gives an esthetic look to the door along with required waterproofing property.
• This method defines the testing procedure to test the jettisoning process and standardizes it thus there are not any variations in the results.
• It holds good even for large size emergency exit doors also hence it is easy to apply and having less weight.
• The application method is very simple so there is not any requirement of special tools or process.
• The load range is defined as per FAR-29.
8. Aim of the invention

The aim of the invention is to establish a well defined and standard process to seal the emergency exit door with the helicopter structure my means of a waterproof sealant and to establish a process of testing the jettisoning mechanism.
9. Summary of the present invention
It gives a method to apply a poly sulphide compound on the composite emergency door by means of controlling width and penetration of the sealant. This is being done by controlled masking width and accurate positioning of foam rubber sheet. It forms a waterproof bridge of rubber seal. To test the jettisoning a fixture has been developed which is a simulation of the actual helicopter as per the dimensions and contour. A load test gauge is being used to measure the applied load and a particular location has been defined to apply the load. It makes the whole process of sealing and testing standard.
10. Brief description of drawings
Fig. 1: emergency exit door on the helicopter.
Fig. 2: Locking mechanism of emergency exit door
Fig. 3: Sealant application gun.
Fig. 4: Holding fixture for sliding door assembly.
Fig. 5: position of the sealant
Fig. 6: Masking of the door
Fig. 7: Load application adapter
Fig. 8: Load test gauge
Fig. 9: Testing on jig
Fig. 10: Rain water test
Fig. 11: Drawing of the Component
11. Statement of invention
This technique establishes a standardized process of sealing of emergency exit door mainly in helicopters along with a standard method to check the jettisoning mechanism and applicable load values.

12. Detailed description of invention
The invention has been carried out in different phases as explained below:
Stage -I
Preparation and masking (fig. 6) of the door for sealant application is one of the important steps in sealant application. The door has to be masked from the both sides of the joggle maintaining 2 mm width all around. By controlling the width of the sealant optimum load only required hence it satisfies both the limits of load, maximum and minimum values.
Stage -II
The foam rubber has to stick by maintaining 1 mm distance from the corner radius. A care has to be taken while placing it as more sealant can flow in and stick and subsequently can require more loads to open the door and on the other hand if it is less than it will easily come out even due to vibration.

Stage -111
The application has to be done by a sealant mixing and application gun (fig. 3). It ensures a uniformly mixed sealant and uniform sealant beading all around the door.
Stage -IV
For the testing the need to be mounted on the jettisoning test fixture which is similar to the helicopter as per dimensions and contour. The door needs to be locked properly at all the 8 locking locations with the clamps. After that the locking mechanism handle has to be operated to disengage the locking pins (fig. 2). The testing has to be done by a load cell carrying load test gauge with a range up to 100 lbs. (fig. 8), a specially designed adapter (fig.7) has to be attached on the load gauge so that a uniform load can be applied. The adapter need to be placed on the designated and marked place on the door and then pushed to open the door (fig. 9)

Results:
20 sets of the doors assembled by the same process have been tested and the jettisoning load values have been recorded. Uniform readings have been achieved and the values were within the desired limits as per the FAR - 29 standard (between 20 lbs - 30 lbs). The sealing has shown excellent waterproofing during rain water test (fig. 10) and withstood the weight of the door even after disengaging the locking pins. It means it will be open only at a load of approximately 30 lbs. So this can be stated that if the locking mechanism is operated in flight, by mistake also it will not be falling down by its own weight.

Claims
• It is a very simple method of sealing the emergency exit window.
• It uses liquid poly sulphide sealant which after curing gets converts into solid rubber beading.
• The liquid sealant flows in the gaps between the emergency exit door and the structure thus provides a watertight sealing.
• The appropriate masking of the emergency exit door and the sliding door provides a controlled glue line thickness which in turn gives the optimum strength to the sealant.
• It gives an esthetic look to the door along with required waterproofing property.
• This method defines the testing procedure to test the jettisoning process and standardizes it thus there are not any variations in the results.
• It holds good even for large size emergency exit doors also hence it is easy to apply and having less weight.
• The application method is very simple so there is not any requirement of special tools or process.
• The load range is defined as per FAR-29.