B737 NG BRIEFINGS
EMERGENCY DESCENT
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This maneuver is designed to bring the airplane down smoothly to a safe altitude, in the minimum time, with the least possible passenger discomfort.
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Use of the autopilot is recommended by Boeing to cover any possible incapacitation (Time of Useful Consciousness is dramatically reduced at high altitude).
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This briefing addresses basic techniques and procedures for a rapid descent. Some routes over mountainous terrain require careful operator planning to include carrying additional oxygen, special procedures, higher initial level off altitudes, and emergency routes in the event a depressurization is experienced.
pilot
BOEING GENERIC QRH
These requirements are normally addressed in an approved company route manual or other document that addresses route specific depressurization procedures. •
An emergency descent is generally preceded by a cabin altitude warning or a rapid depressurization.
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Rapid descents are normally made with the landing gear up. However, when structural integrity is in doubt and airspeed must be limited, extension of the landing gear may provide a more satisfactory rate of descent. If the landing gear is to be used during the descent, comply with the landing gear placard speed
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B737 NG BRIEFINGS •
A generic emergency descent scenario is presented by Boeing in the FCTM:
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Bear in mind that “Special Procedures For In-Flight Contingencies (Emergency Descent Procedures)” are officially requested by a specific ICAO document, applicable in Europe. The Ref ICAO DOC 7030 – Proposal EUR/NAT – S 01/29 – EUR RAC/11 approved T13/4 E – RQ – L030104.ATM is available in the Emergency section of the Jeppesen manual (page EE-21) and is reproduced below: ACTION BY PILOT IN-COMMAND: 1. When an aircraft operated as a controlled flight experiences sudden decompression or a (similar) malfunction requiring an emergency descent, the aircraft shall, if able: a. Initiate a turn away from the assigned route or track before commencing the emergency descent; b. Advise the appropriate air traffic control unit as soon as possible of the emergency descent; c. Set transponder Code to 7700 and select to Emergency Mode on the Automatic on the automatic dependent surveillance/controller-pilot data link communications (ADS/CPDLC) system if applicable; d. Turn on exterior lights; e. Watch for conflicting traffic both visually and by reference to ACAS (if equipped) and f. Coordinate its further intentions with the appropriate ATC unit. 2. The aircraft shall not descend below the lowest published minimum altitude which will provide a minimum vertical clearance of 300 meters (1000 feet) or in designated mountainous terrain 600 meters (2000 feet) above all obstacles located in the area specified. Copyright 2008 - SmartCockpit.com
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B737 NG BRIEFINGS •
It is recommended to use the CTR mode of the EFIS panel to better spot potential conflicting traffics all around position while starting emergency descent. The advantage of using CTR mode instead of EXPANDED mode is to have a 360 degree spotting, as shown below. TWO DIFFERENT VIEWS FOR THE SAME POSITION
EXPANDED MAP Mode
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CENTER MAP Mode
An emergency descent could be exceptionally flown manually even though this scenario is not recommended by Boeing. In this case: The entry may be accomplished on heading or a turn may be made to clear the airway or controlled track. However, since extending the speedbrakes initially reduces the maneuver margin, it is recommended that turns not be initiated until the airplane is established in the descent. Boeing does not specify any specific duty in its FCTM and prefers to give generic information: - disconnect the autothrottles and retard thrust levers to idle. - Smoothly extend the Speedbrakes - Disconnect the autopilot - Smoothly lower the nose to initial descent attitude (approximately 10 degrees nose down). - About 10 knots before reaching target speed, slowly raise the pitch attitude to maintain target speed. - Keep the airplane in trim at all times. - If MMO/VMO is inadvertently exceeded, change pitch smoothly to decrease speed. - Approaching level off altitude, smoothly adjust pitch attitude to reduce rate of descent. - The speedbrake lever should be returned to the down detent when approaching the desired level off altitude. After reaching level flight add thrust to maintain long range cruise or 300 knots. Note: Control Wheel Steering – CWS (if installed) may be used to reduce pilot workload. Follow the manually flown procedure but instead of disengaging the autopilot, engage CWS. Copyright 2008 - SmartCockpit.com
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B737 NG BRIEFINGS EMERGENCY DESCENT
Example based on RYANAIR Procedures CAPTAIN (PF)
FIRST OFFICER (PM)
REMARKS
- Call “EMERGENCY DESCENT RECALL ITEMS”
- Select ENGINE START switches to CONT - Advise ATC “MAYDAY, MAYDAY, MAYDAY, RYANAIR XYZ EMERGENCY DESCENT ON HEADING ___,REQUEST LOCAL QNH” - Squawk 7700 - Turn ON Turnoff and Inboard Landing Lights - Set QNH when obtained - Verify MORA on Jepp Enroute chart
- The local QNH is requested to adapt the level-off altitude
- Read all recall items in silence to check all items have been correctly done (announce any deviation)
- When descending with the A/P engaged and S/B extended at speeds near VMO/ MMO, the airspeed may momentarily increase to above VMO/MMO if S/B are retracted quickly. Retracting smoothly and slowly retract S/B to allow the A/P sufficient time to adjust the pitch attitude to maintain the airspeed within limits.
- Take Public Address and call “EMERGENCY DESCENT, EMERGENCY DESCENT, EMERGENCY DESCENT” (3 times)
1 - Verify autopilot engaged 2 3 4 5 6
- Select lower MCP altitude - Select HDG SEL and turn 45 deg. off Existing Heading or Track, terrain Conditions permitting - Select LVL CHG
- Monitor TCAS - Call “EMERGENCY DESCENT RECALL ITEMS COMPLETE”
- Close thrust levers manually (do not disengage autothrottles) - Extend smoothly the speedbrakes
- Anticipate turbulence and icing requirements.
7 - Adjust MCP Speed
- Call every 10,000 feet during descent.
8 - Set QNH
- Call “TWO TO GO” and “ONE TO GO”
9 - Reset MCP altitude at 10, 000 ft MORA /
MEA whichever is higher and respond to altitude calls by “CHECKED” 10 - Retract Speedbrakes at the call “two to go” and reduce speed at the call “one to go” when approaching level-off altitude
- Public Address call is essential to enable the cabin crew to start their specific duties. - To be able to find the accurate MORA, one pilot at least should have a Jeppesen Enroute chart correctly folded on the part of the route flown by the airplane
- The MCP speed has to be adjusted either to M.82/340 kts or to be limited to current speed (or less) if structural integrity exists or is suspected. Do not assume structural integrity unless it can be positively assured from the flight deck. - High maneuvering loads to be avoided - During descent, the IAS/MACH speed window changes from MACH to IAS at approximately 300 KIAS. Manually reset to VMO as needed. - When reducing speed at the call “one to go”, it will also reduce rate of descent.
LEVEL OFF
If CABIN altitude is at or below 10,000 ft, announce: “I HAVE ATC, REMOVE OXYGEN MASK”
- Reply when appropriate: “YOU HAVE ATC” 1 - Remove headset (around neck)
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- Remove oxygen mask
3 4
- Press to reset oxygen mask and Replace headset - Switch to BOOM on ASP
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- Establish comm with Captain
- F/O verifies pressurization system and advise captain when CABIN ALTITUDE is below 10,000 feet. - Communication capabilities may be significantly enhanced if and when the flight crew can remove oxygen masks.
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B737 NG BRIEFINGS
CAPTAIN
FIRST OFFICER - Reply when appropriate: “I HAVE ATC AND CONTROL”
- Announce: “YOU HAVE ATC AND CONTROL”
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- Remove headset (around neck)
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- Remove oxygen mask
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- Press to reset oxygen mask, put it on the ground and put headset on
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- Switch to BOOM on ASP
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- Establish communication with F/O
- Determine new course of action based on weather, oxygen, fuel remaining, system status, medical condition of crew and passengers and available airports.
- Obtain a new ATC clearance. - Complete NNC.
- Announce over the PA “NUMBER 1 TO THE FLIGHT DECK IMMEDIATELY”. - When in contact with CSS initiate NITS drill by saying “THIS IS A NITS DRILL PLEASE LISTEN CAREFULLY”.
REMARKS - Both pilots have to evaluate the situation: if pressurization is restored, continue manual operation. Emergency descent may be terminated if cabin altitude is controllable. If aircraft is depressurized, remember to descend at a low rate of decent (500 ft/min for optimum passenger comfort) when diverting to the appropriate airfield.
“NUMBER 1 TO THE FLIGHT DECK IMMEDIATELY” indicates an emergency and the CSS will immediately go to the cabin interphone and ask the Captain for NITS. The Captain at this time may decide to unlock the flight deck door and allow the CSS to enter the flight deck for the NITS drill or he may decide to keep the door locked and continue all communication via the interphone. This is at Captain’s discretion. In conducting the NITS, the Captain shall clearly state the individual components of the drill, i.e. “NATURE OF THE PROBLEM IS………...” “INTENTIONS ARE ……………….………..” “TIME AVAILABLE TO LANDING IS ……” “SPECIAL INSTRUCTIONS ARE……..….” The CSS will acknowledge the Captain’s briefing by repeating back the NITS given and must ask for clarification on anything not understood or omitted.
- Make PA announcement to PAX, when time permits.
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B737 NG BRIEFINGS
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Avoid high maneuvering loads. If structural integrity is suspected, remember that use of speedbrakes at speeds in excess of 320 kts could result in a severe vibration which, in turn, could cause extreme damage to the horizontal stabilizer.
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Do not be distracted from flying the aircraft.
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Use of the V/S mode is not recommended.
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Do not forget to reset local QNH.
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Do not forget to take into account cold temperature altitude corrections when doing an emergency descent in a mountainous area.
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