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Two groups have recommended changes to the current JARFAR Regulations Parts 27 and 29, as described in CAA Paper 200506 CAA, 2005. The JAA Helicopter Offshore
Safety and Survivability HOSS working group were concerned that current helicopter ditching requirements preclude the helicopter being capsized by a wave. They cite an
accident when a helicopter ditched and then inverted in severe wave conditions and where all 11 passengers and one crew member escaped through push-out windows in
the cabin. Push-out windows were acknowledged as having made a fundamental contribution to occupant survivability. However, they considered that hand holds close to
the windows would be needed to help occupants to apply sufficient force to ensure removal of the windows. They also considered that emergency lighting systems should
be extended to apply to push-out windows, automatically activated following flooding of the cabin. Their third concern related to the high risk of disorientation following a capsize,
making location and use of push-out windows difficult and looked at optimising seating configuration to reduce possible escape times. HOSS thus recommended Appendix F;
CAA 2005:
FARJAR 27.807 and 29.809 be amended to require that all apertures in passenger compartments suitable for the purpose of underwater escape shall be made
openable in such an emergency, and hand holds should be provided adjacent to such apertures to assist their location and operation. Associated advisory material
should be developed to indicate what constitutes a suitable aperture.
Emergency exit marking systems should also be required on push-out windows and be automatically activated following flooding of the cabin.
Seat rows should be aligned with windows. The FAAJAAIndustry Joint Harmonisation Working Group on Water Impact Appendix G;
CAA, 2005 recommended:
All apertures in the passenger compartment suitable for the purposes of underwater escape shall be equipped so as to be usable in an emergency.
This recommendation was based upon the fact that there were specific regulatory requirements for emergency exits relating to ditching certification, but none for escape
routes underwater in the event of a submersion or capsize. They argued that research and accident experience has shown that occupant survivability is improved when the
opportunity for emergency egress is increased in a water impact. A rule change for helicopters operating over water would allow push-out windows to be marked with
appropriate emergency exit markings and thus improve occupant safety.
4.4 EXIT MECHANISMS AND DESIGN
When considering the ease of use and operation of exits one of the main problems is the wide range of mechanisms found in different helicopter types, their various positions in
relation to the exit and the different directions of operation see RHOSS report, 10.18; CAA, 1995. RHOSS recognised that it must be possible to operate emergency exits in a
crash scenario when individuals may not act in a deliberate and rational manner. A review of helicopter door and window jettison mechanisms for underwater escape by
Brooks and Bohemier 1997 identified 23 different door, hatch and window release mechanisms in 35 different types of helicopter. They found neither standardisation
between helicopter types nor any standardisation in individual designs of helicopter. Some exits required rotation of a lever in a clockwise direction, some in an anticlockwise
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direction, some a pull, some a push action. Whilst many were single action, some had a double action. The position of the operating mechanism differed widely. These authors
called for the use of just two operating mechanisms: one mechanism to fit all doors whether they be in the cockpit or in the passenger cabin, and a second operating
mechanism for all emergency exits and escape windows. Some of the passenger cabin doors and emergency exits described included designs
used in the offshore industry:
Eurocopter AS-332L Super Puma door i.
Pull lever down clockwise; through 60 °
to down vertical position
1
Bell 214 emergency exit i.
Pull lever up clockwise, through 90 °
to up vertical position Sikorsky S-61 stairway
i. Push forward lever;
ii. Rotate lever clockwise through 90
° from left of vertical to right of vertical.
Sikorsky S-76 door i.
Pull cover; ii.
Lift up lever at right angles to fuselage. When considering escape windows, again a number of different means of operation were
found Brooks and Bohemier, 1997: Eurocopter AS-332L Super Puma
i. Pull off shield
ii. Pull tab;
iii. Push out window;
Bell 214 i.
Pull tape ii.
Push out window Sikorsky S-61
i. Lift up using hand recess at base of window;
ii. Pull to release;
iii. Push out window.
Sikorsky S-61 S-76 i.
Pull cap; ii.
Press button; iii.
Lift up lever; iv.
[Push out]. The majority of designs included lanyards or beading that must be removed before the
window could be pushed out. Pull-tabs were located in many different positions. According to an experienced helicopter pilot personal communication the most difficult
action when operating a push-out escape window is the removal of the beading around the window. In his view, if this is done successfully, the window should not be too difficult
to push out. Figure 1 shows a comparison between the dimensions of the emergency exits and escape
windows as defined in the aviation regulations and guidance and the dimensions of two example helicopters, the Eurocopter AS-332L2Super Puma and the Bell 412. The Super
Puma has one door, one Type IV emergency exit and four escape windows, two of which are fitted in the door, on each side of the passenger cabin Figure 2. The Type IV exit
and one escape window are shown in Figure 3. The Bell 412 has two emergency exit windows fitted within a large sliding door, both capable of being jettisoned.
1
All angles and positions of levers described assume that the helicopter is in the upright position.
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Figure 1: Comparison of actual exits with regulations and guidance JARFAR Regulations:
CAA Guidance: Minimum sizes
2
Minimum size
2
suitable for all passengers including large males
Type IV Emergency exit
Push-out window
Eurocopter AS-332L2Super Puma
Type IV Emergency exit size
2
Push-out window size
2
Bell 412 Type IV Emergency exit push-out window size
2
2
Not drawn to scale
660mm 26
483mm 19
680mm 26½
510mm 20
440mm 17½
483mm 19
432mm 17
500mm 19½
686mm 27
559mm 22
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Figure 2: Super Puma door fitted with two escape windows
Figure 3:
Type IV emergency exit and escape window in a Super Puma
4.5 USE OF EXITS IN WATER IMPACT ACCIDENTS
