(1) Servicing of the crew oxygen system is by the replacement of the crew oxygen cylinder
installed in the forward cargo bay.
(2) Servicing of the passenger oxygen system is by the replacement of the chemical generators
which are installed in the service units (PSUs, ASUs and LSUs).
(3) Servicing of the portable oxygen cylinders is by the replacement of the portable oxygen
cylinders with full portable oxygen cylinders.
(4) Use steel or composite oxygen cylinders on the same cylinder support structure.