1 Title of the Invention
Detachable Toe-in Foot Step Door.
2 Field of the Invention
The present invention relates to the technical field of an aircraft, in particular
5 to the technical field of a detachable Toe-in Foot Step Door.
3 Background of the Invention
For personnel get into and out of the cockpits on the left side of an aircraft,
by the use of a retractable footstep, a Toe-in foot step and, an extending
footstep, a footstep on the top of the air intake. The Toe-in Foot Step is fitted
10 above and immediately to the left of the retractable foot step. The Toe-in
Footstep has a back plate which has a door hinged with solid rivets along
its top edge. The door is spring loaded to the closed position, wherein
leading to inaccessibility to restoring spring.
4 Brief Summary of the Invention
15 The present invention describes a method to overcome the inaccessibility
to the spring mechanism which comprise a detachable Toe-in Foot Step
Door. The Toe-in Foot Step has a backplate which has a door hinged with
double lugged anchor and single lugged anchor nut along its top edge. The
door is spring loaded to the closed position.Through the arrangement of
20 anchor nuts, the toe-in foot step door can be directly disassembled by
removing the cruci head screws to restore spring mechanism from corrosion
due to extreme weather conditions ...
5 Detail Description of the Drawings
25 Figure 1: describes the location of the, and, an extending footstep (1 ), a
toe-in footstep (2), retractable footstep (3), a footstep on the top of the air
intake ( 4) on an aircraft.
Figure 2: describes the sectional view of toe-in foot step (12) with door (8)
hinged(?) with and single lugged anchor nuts(5) & double lugged anchor
~ 30 nuts (6) along its top edge with restoring spring(11 ).

Figure 3: describes the construction of detachable toe-in foot step door(8)
hinged(?) with single lugged anchor nuts(5) and double lugged anchor
nuts(6) along its top edge with restoring spring(11 ).
6 Detail Description of the Invention
5 For personnel get into and out of the cockpits on the left side of an aircraft,
by the use of a retractable footstep (3), a toe-in footstep (2) and, an
extending footstep (1 ), a footstep on the top of the air intake (4). The Toein
Foot Step Door (8) usually flushes to the contour of the fuselage (1 0). The
toe-in foot step (2) is fitted above and immediately to the left of the
10 retractable foot step (3). The toe-in foot step door (8) has a stopper (g) fitted,
moves inside the fuselage (10) against the spring (11) tension after
releasing the door (8) comes to the contour profile. The spring (11) is
manufactured using 16 SWG spring steel wire of specification D.T.D 215
and protective treatment to STD 2500 P2+P13. The failure of the spring ( 11)
15 even after the corrosive protective treatment to MIL-C-161730 Grade 1, the corrosion was found. The Corrosion on most of the springs (11) was a cause of concern and has got flight safety connotations. In one of the incidents, toe in flap spring (11) on one aircraft was found broken, the premature failure of spring (11) was attributed to corrosion. With the existing
20 method, If the spring ( 11) to be accessed, the solid rivets need be de-riveted
to access the spring (11) mechanism. However, solid rivets cannot be
riveted again due to inaccessibility and therefore, blind rivets need to be
used after de-riveting and again blind rivets has safety concerns. Therefore,
the present invention discloses a detachable toe-in foot step door(8) to
25 access spring(11) mechanism to mitigate the corrosion issue of toe in door
spring (11 ). The toe-in footstep(2) has a backplate which a door(8)
hinged(?) with single lugged anchor nuts (5), Qty 2 nos and double lugged
anchor nuts(6), Qty 4 nos along its top edge. Through, the arrangement of
anchor nuts(5)(6), the toe-in foot step door(8) can be directly disassembled
30 after removing the screws on the anchor nuts.
Thus prevention invention describes prevention of corrosion due to service
of aircraft in different weather conditions viz. extreme hot, cold and sea water environment and meanwhile, the present invention also describes
corrosion prevention control procedure wherein during minor, minor star
servicing of an aircraft, special note will be introduced for removal of the
detachable toe-in foot step door( B) for restoring spring(11 ). The Spring(11)
5 can be protected against corrosion by spraying the following:
a. Corrosion prevention chemicals
b. Corrosion cleaning spray
c. Corrosion prevention spray
The Corrosion prevention control procedure helps the durability of the
10 restoring to increase.The present invention also provides a scope to
introduce anti skid tape on the toe in foot step rest area(12) wherein the grip
for the pilot foot step increases.

We Claim,
· 1) Detachable Toe-in Footstep Door (8) with toe-in footstep (2) comprising:
a restoring spring ( 11) mechanism through the arrangement of anchor
5 nuts(5)(6);
wherein said toe-in foot step door(8) directly disassembled by removing
the screws, to prevent premature failure of said spring(11) due to
corrosion;
a door(8) hinged (7) with single lugged anchor nut (6) in plurality, along
10 top edge said door (8); and
a door(8) hinged (7) with double lugged anchor nuts (6) in plurality, along
top edge said door (8).
2) Detachable Toe-in Footstep Door (8) with toe-in footstep (2) as claimed
in claim 1, use of corrosion prevention control procedure to increase the
15 durability of spring (11) stiffness.
3) Detachable Toe-in Footstep Door (8) with toe-in footstep (2) as claimed
in Claim 1, use of anti skid tape on pilot toe in foot step ( 12) area.