Airworthiness Directive · Amendment 39-14666 · Boeing Model 737 Airplanes
Boeing Model 737 Airplanes
Superseded. A later AD replaced this one: AD 2008-23-07. Comply with the one in force.
This AD applies to all Boeing Model 737-100, -200, -200C, -300, -400, -500, -600, -700, -700C, -800 and -900 series airplanes, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for all Boeing Model 737 airplanes. This AD requires revising the airplane flight manual to advise the flightcrew of improved procedures for pre- flight setup of the cabin pressurization system, as well as improved procedures for interpreting and responding to the cabin altitude/ configuration warning horn. This AD results from reports that airplanes have failed to pressurize, and that the flightcrews failed to react properly to the cabin altitude warning horn. We are issuing this AD to prevent failure of the airplane to pressurize and subsequent failure of the flightcrew to recognize and react to a valid cabin altitude warning horn, which could result in incapacitation of the flightcrew due to hypoxia (lack of oxygen in body) and consequent loss of airplane control.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Within 60 days after the effective date of this AD, revise the Cabin Pressurization procedures in the Normal Procedures section of the AFMs for Model 737-100, -200, -200C, -300, -400, -500, -600, -700, -700C, -800, and -900 series airplanes to include the following procedure:
“For normal operations, the pressurization mode selector should be in AUTO prior to takeoff.”
(g) Within 60 days after the effective date of this AD, revise the Emergency Procedures section of the AFMs for Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, or the Non-Normal Procedures section of the AFMs for Model 737-600, -700, -700C, -800, and -900 series airplanes, as applicable, to include the following procedure:
Condition: An intermittent or steady warning horn sounds:
• In flight an intermittent horn indicates the cabin altitude is at or above 10,000 feet
• On the ground an intermittent horn indicates an improper takeoff configuration when advancing thrust levers to takeoff thrust
• In flight a steady horn indicates an improper landing configuration.
If an intermittent horn sounds in flight:
| Oxygen Masks and Regulators | on, 100% |
| Crew Communications | Establish |
| Do the Cabin Altitude Warning or Rapid Depressurization checklist. |
If an intermittent horn sounds on the ground: Assure proper airplane takeoff configuration.
If a steady horn sounds in flight: Assure proper airplane landing configuration.”
For Model 737-100, -200, -200C, -300, -400, and -500 series airplanes: Using the phrase, “If the intermittent cabin altitude/configuration warning horn sounds in flight:” in place of the phrase, “If the cabin altitude warning horn sounds:”, in the revisions to the “Cabin Altitude Warning or Rapid Depressurization” procedure specified in Figures 2 and 3 of AD 2003-03-15 R1, is acceptable for compliance with the requirements of paragraph (a) of AD 2003-03-15 R1. All other requirements of AD 2003-03-15 R1 remain unchanged.
(i) For Model 737-600, -700, -700C, -800, and -900 series airplanes: Using the phrase, “If the intermittent cabin altitude/configuration warning horn sounds in flight:” in place of the phrase, “Condition: The cabin altitude warning horn sounds:”, in the revisions to the “Cabin Altitude Warning or Rapid Depressurization” procedure specified in Figure 1 of AD 2003-14-08, is acceptable for compliance with the requirements of paragraph (a) of AD 2003-14-08. All other requirements of AD 2003-14-08 remain unchanged.
The AFM revisions specified in paragraphs (f) and (g) of this AD may be done by inserting a copy of this AD into the AFM.
(k) When statements identical to those specified in paragraphs (f) and (g) of this AD have been included in general revisions of the AFM, then the general revision(s) may be inserted into the AFM, and the copy of the AD may be removed from the applicable revised sections of the AFM.
