# AD 91-10-05: Oxygen Mask Presentation Units - Type: Airworthiness directive - Status: Current - Products: Bombardier CL-600-1A11 (CL-600), CL-600-2A12 (CL-601), CL-600-2B16 (CL-601-3A), CL-600-2B16 (CL-601-3R), CL-600-2B16 (CL-604), Mystere-Falcon 20 - C5, Mystere-Falcon 20 - D5, Mystere-Falcon 20 - E5, Mystere-Falcon 20 - F5, G-1159, G-1159A, G-1159B and 5 more - Effective: June 3, 1991 - Superseded by: Nothing supersedes this AD - Product type: Appliance - Amendment: 39-6989 - Docket: 90-CE-43-AD - Registered aircraft: 1,152 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/AFAC2C50822E286786256A410063CC96.0001 - DRS record last changed: January 21, 2026 - Page: https://openairdocs.org/ad/91-10-05 ## The airworthiness directive 91-10-05 O2 CORPORATION (FRANK MCGOWAN CO.): Amendment 39-6989. Docket No. 90-CE-43-AD. Applicability: The following Mask Presentation Unit Part Numbers that are installed on, but not limited to, British Aerospace 125-800A airplanes; Challenger CL600-1A11, CL600-2B16, and CL600-2A12 airplanes; Gulfstream G-1159, G-1159A, G-1159B, and G-IV airplanes; and Falcon 20 airplanes, certificated in any category: 121-040-04 150-004-03 151-020 150-002 150-004-04 151-020-02 150-002-01 150-004-05 151-020-04 150-002-02 150-004-06 152-001 150-002-03 150-004-07 152-001-01 150-002-04 150-004-08 152-001-04 150-002-05 150-004-12 152-001-05 150-002-08 150-005 152-001-08 150-003T 150-006 152-001-13 150-003-04T 150-022 152-003 150-004 151-010 152-004 150-004-01 151-010-02 152-004-05 150-004-02 151-010-04 Compliance: Required within the next 3 calendar months after the effective date of this AD, unless already accomplished. To prevent malfunctioning of the lanyard release pin that could prevent the flow of oxygen to a passenger in an emergency situation, accomplish the following: (a) With the oxygen system activated, perform a test of the lanyard release pins by accomplishing the following: (1) Open the passenger mask presentation units of the airplane and allow the mask assemblies to drop out. (2) Make up a 7.5 pound weight with an attached string and hook, (e.g., spring, clip, etc.). (3) Attach the hook to the lanyard attaching point of each actuator pin without dropping the weight and allow the weight to hang from the lanyard attaching point. (b) If the pin pulls free from the oxygen actuator valve at 7.5 pounds or less of hanging weight, then the pin is satisfactory and the unit may be returned to service. (c) If the pin does not pull free from the oxygen actuator valve using the test required by paragraph (a) of this AD, prior to further flight accomplish the following:(1) Replace the pin with either part number 100-111-2 or 100-111-3, which has a 20-degree angle and a rounded nose. NOTE 1: The pin is available from the manufacturer by contacting Mr. Burt Parry, O2 Corporation, 3522 N. Comotara, Wichita, Kansas 67226; Telephone (316) 634-1240; Facsimile (316) 634-1061. (2) Test the replacement pin installation in accordance with the test requirements of paragraph (a) of this AD to assure that the lanyard pin can be removed with a pull of 7.5 pounds or less. If the pin pulls free from the oxygen actuator valve at 7.5 pounds or less of hanging weight, then the pin is satisfactory and the unit may be returned to service. (d) An alternate method of compliance or adjustment of the compliance time that provides an equivalent level of safety may be approved by the Manager, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas; Telephone (316) 946-4419. The request should be forwardedthrough an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Wichita Aircraft Certification Office. (e) All persons affected by this directive may obtain copies of any information that is applicable to this AD from the FAA, Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 90-CE-43-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106. Replacement parts that might be needed to complete the actions of this AD may be obtained from Mr. Burt Parry, O2 Corporation, 3522 N. Comotara, Wichita, Kansas 67226; Telephone (316) 634-1240; Facsimile (316) 634-1061. This amendment (39-6989, AD 91-10-05) becomes effective on June 3, 1991. ## Affected data sheets (4) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A12EA](https://openairdocs.org/tcds/A12EA): Gulfstream Aerospace Corporation; names 4 of 7 models: G-1159A, G-IV, G-1159B, G-1159 - [TCDS A7EU](https://openairdocs.org/tcds/A7EU): Dassault Aviation; names 4 of 11 models: Mystere-Falcon 20 - D5, Mystere-Falcon 20 - C5, Mystere-Falcon 20 - F5, Mystere-Falcon 20 - E5 - [TCDS A21EA](https://openairdocs.org/tcds/A21EA): Bombardier Inc.; names 3 of 5 models: CL-600-1A11 (600), CL-600-2A12 (601), CL-600-2B16 (604 Variant) - [TCDS A3EU](https://openairdocs.org/tcds/A3EU): Textron Aviation Inc.; names 1 of 50 models: BAe.125 Series 800A (U-125) ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 1,152 (1,152 by airframe model, 0 by engine model) - Makers: Bombardier 432, Gulfstream Aerospace 411, Canadair 164, British Aerospace 66, Gulfstream American 29, Dassault-Breguet 14, Grumman 9, Corporate Jets 8, Raytheon Corporate Jets 8, Grumman American Avn. 4 Models with the most aircraft: - [Bombardier CL-600-2B16](https://openairdocs.org/model/bombardier-cl-600-2b16): 388 aircraft (airframe model) - [Gulfstream Aerospace G-IV](https://openairdocs.org/model/gulfstream-aerospace-g-iv): 357 aircraft (airframe model) - [Canadair CL-600-2B16](https://openairdocs.org/model/canadair-cl-600-2b16): 134 aircraft (airframe model) - [British Aerospace BAE 125 SERIES 800A](https://openairdocs.org/model/british-aerospace-bae-125-series-800a): 61 aircraft (airframe model) - [Bombardier CL-600-2B16(CL-604)](https://openairdocs.org/model/bombardier-cl-600-2b16-cl-604): 42 aircraft (airframe model) - [Gulfstream Aerospace G-1159A](https://openairdocs.org/model/gulfstream-aerospace-g-1159a): 32 aircraft (airframe model) - [Gulfstream American G-1159A](https://openairdocs.org/model/gulfstream-american-g-1159a): 27 aircraft (airframe model) - [Canadair CL-600-2A12](https://openairdocs.org/model/canadair-cl-600-2a12): 19 aircraft (airframe model) - [Dassault-Breguet MYSTERE FALCON 20-F5](https://openairdocs.org/model/dassault-breguet-mystere-falcon-20-f5): 10 aircraft (airframe model) - [Gulfstream Aerospace G1159B](https://openairdocs.org/model/gulfstream-aerospace-g1159b): 10 aircraft (airframe model) - [Corporate Jets BAE 125-800A](https://openairdocs.org/model/corporate-jets-bae-125-800a): 8 aircraft (airframe model) - [Grumman G-1159](https://openairdocs.org/model/grumman-g-1159): 8 aircraft (airframe model) - [Gulfstream Aerospace G-IV (G400)](https://openairdocs.org/model/gulfstream-aerospace-g-iv-g400): 8 aircraft (airframe model) - [Raytheon Corporate Jets BAE 125-800A](https://openairdocs.org/model/raytheon-corporate-jets-bae-125-800a): 8 aircraft (airframe model) - [British Aerospace BAE 125-800A](https://openairdocs.org/model/british-aerospace-bae-125-800a): 5 aircraft (airframe model) - [Canadair CL-600-1A11](https://openairdocs.org/model/canadair-cl-600-1a11): 5 aircraft (airframe model) - [Grumman American Avn. G-1159](https://openairdocs.org/model/grumman-american-avn-g-1159): 4 aircraft (airframe model) - [Canadair CL600-2B16(CL601-3A)](https://openairdocs.org/model/canadair-cl600-2b16-cl601-3a): 3 aircraft (airframe model) - [Dassault-Breguet MYSTERE FALCON 20-C5](https://openairdocs.org/model/dassault-breguet-mystere-falcon-20-c5): 3 aircraft (airframe model) - [Canadair CL600-1A11](https://openairdocs.org/model/canadair-cl600-1a11): 2 aircraft (airframe model) All 34 models: https://openairdocs.org/ad/91-10-05/models.md Every aircraft: https://openairdocs.org/ad/91-10-05/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.