AD 75-04-03

75-04-03 MCDONNELL DOUGLAS: Amendment 39-2085. Applies to Douglas Model DC-10-10, -30, and -40 Series airplanes, certificated in all categories.

Compliance required as follows unless already accomplished.

To improve cabin oxygen mask deployment reliability, accomplish the following:

A. Within the next 300 hours' additional time in service after the effective date of this AD, unless already accomplished within the last 300 hours' time in service:

1. Conduct an oxygen mask functional (drop) test, by cabin or by each section, in accordance with Paragraph IX of Douglas All Operators Letter No. 10-742, dated December 13, 1974, or 10-742A, dated January 24, 1975, or later FAA-approved revisions.

2. Oxygen compartments that fail to open must be inspected and modified in accordance with all of the applicable provisions of Douglas All Operators Letter No. 10-742, dated December 13, 1974, or 10-742A, dated January 24, 1975, or later FAA-approved revisions.

3.Repeat the oxygen mask functional test until 100% mask drops are achieved by cabin or by each section.

B. Within the next 1500 hours' additional time in service after the effective date of this AD:

1. Modify partition oxygen compartment doors to insure 180 degrees opening in accordance with Douglas Service Bulletin No. 25-163, dated June 11, 1974, or later FAA-approved revisions.

2. Install pictorial warning placards on oxygen generator heat shields in accordance with Douglas Service Bulletin No. 35-12, dated April 26, 1974, or later FAA-approved revisions.

3. Modify oxygen compartments in passenger seat backs and partitions in accordance with Douglas Service Bulletin No. 35-16, dated August 19, 1974, or later FAA-approved revisions.

4. (a) Inspect and modify the cabin oxygen system, as applicable, in accordance with Douglas All Operators Letter No. 10-742, dated December 13, 1974, or 10-742A, dated January 24, 1975, or later FAA-approved revisions.(b) Repeat the oxygen mask functional test until 100% mask drops are achieved by cabin or by each section.

C. Results of the functional tests required in paragraphs A. and B. must be forwarded within 30 days in a written report to the Chief, Aircraft Engineering Division, FAA Western Region. Recording approved by the Bureau of the Budget under Order BOB No. 04-R0174.

D. The Chief, Aircraft Engineering Division, FAA Western Region, may approve equivalent inspections and modifications upon submittal of substantiating data.

E. Aircraft may be flown to a base for accomplishment of the maintenance required by this AD per FAR's 21.197 and 21.199.

This amendment becomes effective February 14, 1975.