Access cover

1. An access cover for an aircraft hole comprising:

a plurality of access cover holes,

an inner surface configured to face towards the aircraft hole,

a plurality of first projections protruding from the inner surface, and

a plurality of fixing elements configured to fix the access cover to a supporting structure of the aircraft hole, each fixing element comprising:

a male fixing element having an outer threaded surface, the male fixing element being configured to pass through one of the plurality of access cover holes, and

a locking element comprising a threaded hole and an extended portion, wherein the outer threaded surface of the male fixing element is configured to thread with the threaded hole of the locking element,

wherein the male fixing elements, the locking elements and the first projections are configured such that when a male fixing element inserted through an access cover hole and through a locking element is rotated in a lock direction, friction between the male fixing element and the locking element causes the locking element to rotate with the male fixing element until rotational movement of the locking element is stopped by one of the first projections, and further rotation of the male fixing element in the lock direction causes a threading of the locking element with the male fixing element, the access cover further comprising a plurality of second projections protruding from the inner surface, wherein each second projection is configured to limit the rotational movement of the locking element when the male fixing element inserted through the one of the plurality of access cover holes and through the locking element is rotated in a release direction, the release direction being opposite to the lock direction, and wherein the first projection has a first height with respect to the inner surface and the second projection has a second height with respect to the inner surface, the second height being smaller than the first height,

wherein each second projection defines, together with a first projection, a housing comprising a wall extending from the first projection to the second projection, and

wherein the wall of the housing has a height with respect to the inner surface which monotonically increases from the second projection to the first projection.

2. The access cover according to claim 1 , wherein the inner surface comprises a peripheral portion suitable for being supported on the supporting structure of the aircraft hole.

3. The access cover according to claim 2 , wherein in a position where the rotational movement of the locking element is limited by the one of the plurality of first projections, an extended portion of the locking element is positioned over a peripheral portion of the access cover.

4. The access cover according to claim 3 , wherein in a position where the rotational movement of the locking element is limited by the one of the plurality of first projections, the extended portion of the locking element protrudes beyond the peripheral portion of the access cover.

5. The access cover according to claim 2 , wherein a central portion of the access cover has a thickness less than a thickness at a peripheral portion of the access cover.

6. The access cover according to claim 1 , further comprising a plurality of outstanding portions, wherein each outstanding portion protrudes from the inner surface and wherein each of the plurality of access cover holes is located in an outstanding portion.

7. The access cover according to claim 3 , wherein the extended portion of the locking element comprises a third projection configured to contact the supporting structure of the aircraft hole.

8. An aircraft comprising:

at least one aircraft hole, and

an access cover according to claim 1 .