Sunday, 27 March 2011

Dutch Door

Dutch Doors

The next structural difference we will discuss is the “Dutch Doors” on the starboard side of the fuselage. As the upper “Dutch Door” is the same on both aircraft, there is no need to discuss this particular component.  The lower doors however, are completely different.  Both Labradors and Voyageurs were fitted with the standard CH-46/KV-107 lower door with a full width piano hinge on the bottom of the door, unlike later model Japanese KV-107s that were eventually fitted with aft sliding doors. The Voyageur’s lower door, unlike the Labrador’s door, which was also hinged to the right side of the fuselage and lowered outwards were equipped with steps.  Once opened and secured in the lowered position persons emplaning or deplaning simply used steps built into the lower door.

The Labrador on the other hand routinely used the door operationally, thus Voyageur style steps were more of an encumbrance than a convenience.  In fact, the door was utilized operationally whether the mission involved hoisting or placing the aircraft in the water, so door design went beyond encumbrance it was an important operational change.

From a design standpoint, the Labrador lower doors differed in that they incorporated a slide and rungs to accommodate delivery and recovery of search and rescue personnel in a variety of situations.  When hoisting or conducting similar operations from the front of the aircraft, the door was pinned completely underneath the aircraft to prevent ropes, hoist cables and/or equipment from snagging on the door.  The door was also pinned underneath the fuselage when search and rescue person were dispatched in the water (with or without scuba tanks) in what was called a “front door entry”. Although a less common occurrence, the door could alternatively be pinned in a horizontal position to conduct front door entries.

When deplaning or emplaning, the Labrador’s lower Dutch Door was secured at about a 45-degree angle and the rungs used as steps.  This position was also used when recovering search and rescue personnel from the water, a procedure referred to as “front door pickup”.  More often then not when a front door pickup was being executed a door extension was attached to the end of the door.  The extension made it easier for personnel being recovered to grab and pull themselves into the aircraft, with or without the assistance of a Flight Engineer (FE).
As Voyageurs were integrated into the SAR fleet, it was readily apparent the step style lower Dutch door would need to be changed before the Voyageur could be a more efficient rescue resource. While the  Voyageur style door would not necessarily affect hoist operations, it would negate the use of the door for front door entry and front door pickup procedures – a common and oft trained SAR procedure in the 1960, 70s and ‘80s .  Voyageurs slated for modification sometime after 1975, as part of what became the “Speedline Program” would be the first to get Labrador style lower Dutch Doors. Eventual1y, all Voyageur lower Dutch Doors were modified to that of the Labrador.

The brace to pin the Labrador’s lower Dutch door underneath the airframe differed initially, however the initial style brace was removed in favour of that used by search and rescue modified Voyageurs. Prior to being used in SAR, Voyageurs did not require a brace.

Early Labrador braces were red in colour whereas the newer braces for both the Labrador and modified Voyageurs were either gray or yellow. The brace on SARCUP aircraft was capable of securing the lower Dutch door in one position only, directly under the aircraft. The next blog will discuss the Emergency exit on the left side of the fuselage.


No comments:

Post a Comment