On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below repeals Airworthiness Directive (AD) AD/B737/346 and issues the following AD under subregulation 39.001(1) of CASR 1998 and subsection 33(3) of the Acts Interpretation Act1901. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.
Boeing 737 Series Aeroplanes
AD/B737/346 Amdt 1
Cabin Altitude Warning Takeoff Briefing
Boeing Model 737-100, -200, -200C, -300, -400, -500, -600, -700, -700C, -800,
-900 and -900ER series aeroplanes.
1. Revise the Limitations Section of the applicable Boeing 737 Aircraft Flight Manual (AFM) to include the following statement:
“CABIN ALTITUDE WARNING TAKEOFF BRIEFING
With the CABIN ALTITUDE and TAKEOFF CONFIG lights not installed, or installed but not activated:
As part of the Takeoff Briefing before engine start for the first flight of the day or following any change of either flightcrew member, the pilot-in-command will ensure the Cabin Altitude Warning indications and procedures are briefed in accordance with the procedures contained in the Normal Procedures section of this manual.”
2. Revise the Normal Procedures Section of the applicable Boeing 737 AFM to include the following statement:
“CABIN ALTITUDE WARNING TAKEOFF BRIEFING
The following briefing is important to further reduce the risk of flightcrew incapacitation due to hypoxia. Because of the dual purpose of the intermittent cabin altitude/takeoff configuration warning horn, this briefing serves to remind flightcrews that the sounding of the cabin altitude warning horn in flight requires immediate action, beginning with the immediate donning of oxygen masks. Upon completion of the applicable WARNING HORN—CABIN ALTITUDE OR CONFIGURATION non-normal checklist memory items, other alerts and indications on the flight deck (e.g., air/ground sensing system failures, equipment cooling OFF, etc.) may then be addressed.
Memory item cabin altitude warning indications and procedures must be briefed on airplanes in which the CABIN ALTITUDE and TAKEOFF CONFIG lights are not installed, or are installed but not activated. This will be included as an additional item on the Takeoff briefing before engine start for the first flight of the day, or following any change of either flightcrew member.
The briefing must include the following items.
- Whenever the intermittent warning horn sounds in flight:
1. Immediately, don oxygen masks and set regulators to 100%.
2. Establish crew communications.
3. Do the CABIN ALTITUDE WARNING OR RAPID DEPRESSURIZATION checklist.
- Both pilots must verify on the overhead Cabin Altitude Panel that the cabin altitude is stabilized at or below 10,000 feet before removing oxygen masks.”
The above actions may be accomplished by inserting a copy of this Directive into the applicable AFM.
The Requirement 1 and 2 AFM revisions may be removed from the applicable AFM when the information they contain is inserted in the AFM by a normal or temporary revision.
Note: FAA AD 2008-23-07 Amdt 39-15728 refers.
For Requirements 1 and 2 - Within 120 days after the effective date of this Directive.
Revising the AFM as per the approved FAA AMOC Letter 130S-09-134a dated
28 April 2009 is an alternate means of complying with requirement 2 of this AD.
The effective date of this Amendment is 30 September 2013.
The United States Federal Aviation Administration (FAA) had advised of the receipt of continuing reports that flightcrew have failed to recognize and react properly to the cabin altitude warning horn. This Directive is issued to prevent 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 aeroplane control.
Amendment 1 allows the revising of the AFM as per the approved FAA AMOC Letter 130S-09-134a dated 28 April 2009 as an alternate means of complying with requirement 2 of this AD.
The original issue of this AD became effective on 25 November 2008.
Delegate of the Civil Aviation Safety Authority
10 September 2013