B737 Memory Items (Recall Items)

Most failures on the Boeing 737 are handled by reading a non-normal checklist (NNC) from the quick reference handbook (QRH). A few cannot wait for the book to be found and opened. Those checklists begin with recall items, usually called memory items, which the crew performs from memory; the reference items that follow are read and done from the QRH. The rejected take-off, the stall and upset recoveries and the windshear and terrain escapes are flown from memory from start to finish.

This article gives the recall items as the 737 NG QRH and FCOM describe them, with the 737 MAX differences where they are known. Recall items change with QRH revisions, and the Runaway Stabilizer checklist was rewritten after the MAX accidents, so the operator's current QRH, and its own procedures, always govern over any summary, this one included. The wider principles are in standard operating procedures and checklists.

Recall items and the non-normal checklist

A recall item covers only what is urgent: oxygen on, the autothrottle off, a lever closed, a manoeuvre started. Everything else is a reference item. In Airspeed Unreliable, for example, checking the probe heat ON and cross-checking the captain's, first officer's and standby airspeeds are reference items read after the recall steps. Many recall lines are conditional, "if engaged" or "if the light remains illuminated", and the condition is part of what must be remembered.

One action recurs. The engine limit, engine fire and overheat, uncommanded roll, airspeed unreliable, runaway stabiliser, stall and rejected take-off sequences all disengage the autothrottle. The engine limit checklist gives the reason: with the autothrottle disengaged, the thrust lever stays where the pilot puts it.

The 737 FCOM has a second memory list. Limitations marked # are memory items that the crew must comply with without the manual: among them a 10 kt maximum take-off and landing tailwind, 280 KIAS or M 0.76, whichever is lower, for severe turbulence penetration in climb and descent, no autopilot engagement below 400 ft AGL after take-off and a 20,000 ft maximum altitude with flaps extended. A limitation is complied with; a recall item is performed (see B737 limitations).

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Rejected take-off

The rejected take-off (RTO) is flown entirely from memory, with the two pilots' actions overlapping:

1. The captain calls "REJECT" and, at the same time, closes the thrust levers, disengages the autothrottle and applies maximum manual braking or checks that the RTO autobrake is working. If the AUTO BRAKE DISARM light comes on or the deceleration is not adequate, manual braking is applied.
2. The captain raises the SPEED BRAKE lever and applies maximum reverse thrust consistent with the conditions, braking to the maximum until certain of stopping on the runway.
3. The first officer checks the actions and calls "SPEEDBRAKES UP" or "NO SPEEDBRAKES", then "60 KNOTS".
4. Field length permitting, the reverse thrust levers are brought back to reach the reverse idle detent by taxi speed.

The tower and cabin are told as soon as practical. Once stopped, the parking brake is not set unless the passengers must be evacuated, and the Brake Cooling Schedule gives the cooling time.

With the AUTO BRAKE select switch at RTO, maximum brake pressure is applied automatically when the thrust levers are retarded to idle at or above 90 kt; below 90 kt autobraking does not begin. With the SPEED BRAKE lever DOWN, as it is for take-off, the automatic speedbrake deploys only when the main wheels spin up above 60 kt, both thrust levers are at idle and the reverse levers are positioned for reverse, which is why the lever's position is checked and called rather than assumed (see take-off procedures and rejected take-off).

Engine fire, severe damage or separation

The Engine Fire, Severe Damage or Separation recall items:

1. Autothrottle (if engaged): disengage.
2. Thrust lever of the affected engine: close. This also helps confirm which engine is affected.
3. Engine start lever: CUTOFF.
4. Engine fire switch: pull, pressing the override if it is still locked.
5. If the fire switch or ENG OVERHEAT light stays illuminated: rotate the switch to a stop and hold for one second.
6. If after 30 seconds the warning remains: rotate it to the other stop and hold for one second, discharging the second bottle.

The switches and bottles are described in B737 fire protection.

Three shorter engine recalls share the opening. Engine Overheat: autothrottle disengage and thrust lever close; if the ENG OVERHEAT light remains, the full fire checklist follows. Engine Limit, Surge or Stall: autothrottle disengage, then retard the thrust lever until the engine indications stabilise within limits, or until the lever is closed. Aborted Engine Start, called for a hung start, no oil pressure by stable idle, no EGT rise within 15 seconds or an EGT quickly nearing or exceeding the start limit, has a single item: start lever CUTOFF (see B737 engines and engine indications).

Loss of thrust on both engines

1. ENGINE START switches: FLT, for continuous ignition.
2. ENGINE START levers: CUTOFF, interrupting the fuel.
3. When EGT is decreasing: ENGINE START levers to IDLE detent, to attempt a relight.
4. On the NG, if EGT reaches 950 °C on an engine: that start lever to CUTOFF, then back to IDLE detent.
5. Repeat the start lever steps as needed until a relight is achieved.

The 950 °C step is given for the NG; MAX crews follow their own QRH.

Approach to stall and stall recovery

The Approach to Stall or Stall Recovery procedure begins by holding the control column firmly and disengaging the autopilot and autothrottle: the shaker and buffet invite a pull, and an engaged autothrottle can add thrust on its own. The pilot flying then:

1. smoothly applies nose-down elevator to reduce the angle of attack until the buffet or stick shaker stops, with nose-down stabiliser trim if needed;
2. rolls the wings level;
3. advances thrust as needed, once the angle of attack has been reduced;
4. retracts the speedbrakes;
5. leaves the flaps and landing gear alone, and returns to the desired flight path once the stall indications have stopped.

Height loss is accepted: holding altitude with back pressure keeps the wing stalled. At high altitude the pitch attitude may have to go below the horizon to accelerate; close to the ground the nose-down input is no larger than needed to stop the indications. The pilot not flying (PNF) monitors altitude, airspeed and terrain and calls any omitted action.

Thrust comes after the pitch input for a reason. The underwing engines produce a nose-up couple, so thrust added while the wing is still stalled drives the angle of attack back up; leading with maximum thrust was withdrawn from this procedure. If nose-down authority is short, reducing thrust may even be necessary. On the NG the autopilot disengages by itself if the stick shaker persists for more than five seconds (see stall).

Nose high and nose low upset recovery

Both recoveries open with recognise and confirm the situation, then autopilot and autothrottle disconnect.

• Nose high: apply as much as full nose-down elevator and appropriate nose-down stabiliser trim; reduce thrust, because the underwing engines' nose-up couple opposes the recovery; roll, if needed, to obtain a nose-down pitch rate. Approaching the horizon, roll wings level, adjust thrust and establish the pitch attitude.
• Nose low: recover from a stall first if required; roll in the shortest direction to wings level; then apply nose-up elevator, nose-up trim if required, and adjust thrust and drag.

In both, the PNF calls out attitude, airspeed and altitude. A Boeing warning applies to both: excessive use of pitch trim or rudder may aggravate an upset or cause loss of control (see upset prevention and recovery).

Windshear and GPWS manoeuvres

These are the escapes in which the threat is outside the aeroplane, so they use maximum thrust and may pitch up towards the stall warning rather than away from it.

Ground proximity warning (PULL UP): disconnect the autopilot and autothrottle and apply maximum thrust; roll wings level while pitching to an initial 20° nose-up; retract the speedbrakes. If terrain remains a threat, continue rotation up to the pitch limit indicator, stick shaker or initial buffet. Gear and flaps stay as they are until terrain separation is assured, and when clear the pitch is reduced slowly while accelerating. On the NG, with the EECs in normal mode, the thrust levers may go full forward. The PNF monitors vertical speed and altitude. A ground proximity caution needs only a correction of flight path or configuration.

Windshear, manual flight: disengage the autopilot, press either TO/GA switch and apply maximum thrust, pitch to an initial 15°, retract the speedbrakes and follow the flight director's TO/GA guidance if available. Automatic flight: press either TO/GA switch, verify the TO/GA annunciation and that thrust advances to go-around power, retract the speedbrakes and monitor; the crew must be ready to disconnect the autopilot and autothrottle and fly by hand if the shear exceeds the system's performance. In both, configuration is not changed and lost airspeed is not chased until windshear is no longer a factor, and the pitch limit is intermittent stick shaker or initial buffet.

Runaway stabiliser, uncommanded rudder and airspeed unreliable

The Runaway Stabilizer recall items, now shared by the NG and MAX QRHs, cover stabiliser movement that is continuous or wrong for the conditions:

1. Control column: hold firmly.
2. Autopilot (if engaged): disengage, and do not re-engage.
3. Autothrottle (if engaged): disengage.
4. Control column and thrust levers: control pitch attitude and airspeed.
5. Main electric trim: reduce control column forces.
6. If the runaway continues: both STAB TRIM CUTOUT switches to CUTOUT.
7. If it still continues: grasp and hold the stabiliser trim wheel.

Training stresses trying main electric trim before cutting it out, and the checklist notes that reducing airspeed makes manual trimming easier. On the MAX an MCAS command is not stopped by pulling the column, but both cutout switches at CUTOUT stop it (see B737 pitch controls and stabiliser trim).

Uncommanded Rudder, Yaw or Roll: autopilot disengage; control the aeroplane with all available flight controls; if roll is uncontrollable, immediately reduce pitch attitude and angle of attack and increase airspeed, without trying to hold altitude; once roll is controllable, disengage the autothrottle and check that thrust is symmetrical.

Airspeed Unreliable: disengage the autopilot and autothrottle, set both flight director switches OFF, then set the memorised pitch and thrust: 10° and 80 % N1 with flaps extended, 4° and 75 % N1 with flaps up. The reference items and the QRH tables follow. On the MAX, AOA DISAGREE also leads to this checklist, and EASA's version allows the crew to silence an erroneous stick shaker by its circuit breaker, an option the FAA rejected (see unreliable airspeed).

Cabin altitude warning, rapid depressurisation and emergency descent

The Warning Horn recall decides on two facts. An intermittent horn in flight is the cabin altitude warning; on the ground it is the take-off configuration warning; a steady horn in flight is the landing configuration warning. The crew of Helios Airways Flight 522, a 737-300, took the cabin altitude warning for the take-off configuration warning in 2005 and were overcome by hypoxia.

Cabin Altitude Warning or Rapid Depressurisation:

1. Oxygen masks and regulators: ON, 100 %.
2. Crew communications: establish.
3. PRESSURIZATION MODE selector: MAN.
4. OUTFLOW VALVE switch: CLOSE; if pressurisation is restored, continue manual operation.
5. PASSENGER OXYGEN switch: ON if the cabin altitude exceeds, or is expected to exceed, 14,000 ft.
6. Emergency descent if above 14,000 ft MSL and the cabin cannot be controlled, or if cabin pressure is lost.

The masks come off only when both pilots have verified that the cabin altitude is stabilised at or below 10,000 ft.

Emergency Descent: the captain announces it to the cabin on the PA and the first officer advises ATC and obtains the altimeter setting; ENGINE START switches CONT; thrust levers closed, or as needed for anti-ice; SPEED BRAKE to the FLIGHT DETENT; target speed Mmo/Vmo, lower with structural damage suspected and avoiding high manoeuvring loads; level off at the lowest safe altitude or 10,000 ft, whichever is higher (see decompression).

Library articles are written for study and exam preparation. They do not replace your aircraft's approved documentation, your operator's procedures or the regulations themselves.