B737-400 Oral Exam Questions &
Answers
21 In simple terms, what does this valve do? - ANSWERAns: it connects the engine
feed system with the refueling station.
22 What is the primary source for DC power? - ANSWERAns: three normal TRs and a
ground service TR (battery charger)
32 If a leak developed in the lines of the electric pump and all pressure was lost, would
the PTU still be operational? - ANSWERAns: yes
27 What happens to the engine bleed valves upon engine shutdown? - ANSWERAns:
they automatically close (pneumatically)
06 What devices provide the pilots with control feel? - ANSWERAns: the feel
mechanism (ailerons & rudder) and the elevator feel computer
12 Does the engine bleed valve regulate a minimum value? - ANSWERAns: no, at less
than 45 psi, they are full open.
31 How do the reversers operate? - ANSWERAns: fan air is deflected forward by a
translating sleeve on the engine cowling.
07 If a leak developed in the "A" system engine driven pump, what indication would you
expect to see on the quantity gauge? - ANSWERAns: the quantity gauge would read
one quarter full.
10 Does this mean that the yaw damper is still effective with a loss of "B" system
pressure? - ANSWERAns: no, the system is still sensing, but cannot function without
"B" system pressure
43 What is the function of the reverse interlock? - ANSWERAns: it limits the amount of
thrust which can be applied when the reversers are in the incorrect position for the
forward or reverse thrust commanded.
26 When is the forward outflow closed? - ANSWERAns: when the main outflow valve is
within 1/2 degree of being closed or whenever the recirculating fan is operating,
33 When you pull an ENGINE FIRE WARNING SWITCH, what actions take place? -
ANSWERAns: 1. One discharge squib is armed on each fire bottle. 2. Closes the: A.
Fuel shutoff valve. B. Bleed air C. Thrust reverser, and D. Hydraulic shutoff valve. 3.
Trips the generator control relay and generator breaker. 4. Disarms the associated
,hydraulic "LOW PRESSURE" light. Allows the switch to be rotated. (2 arms, 3 closes, 1
trip, 2 disables)
14 How do you know that the RTO is operational? - ANSWERAns: when RTO is
selected, the "AUTO BRAKE DISARM" light illuminates for approximately 2 seconds, as
a self-test.
73 Why is the automatic transfer of the Standby Busses inhibited on the ground? -
ANSWERTo prevent excessive drain of the battery under normal ground operations
(after shutdown, for example.)
29 Which annunciator lights illuminate with a loss of "B" system pressure? -
ANSWERAns: 1. MASTER CAUTION 2. FLT CONTROL 3. HYD 4. SYSTEM "B" FLT
CONTROL LOW PRESSURE 5. SYSTEM "B" ENG & ELEC PUMP LOW PRESS 6.
FEEL DIFF PRESS
22 How many lights would you expect to see illuminated during this test? -
ANSWERAns: five.
03 What does it mean if the Autothrottle disengage light is flashing amber? -
ANSWERThere is an autothrottle speed error. The autothrottle is not holding speed
within +10 or - 5 knots of commanded speed when in flight, flaps not up, and
autothrottle engaged MCP SPD or FMC SPD mode.
17 Is this a self-powered probe? - ANSWERAns: no, it uses AC power.
APU: Maximum Altitude for APU electrical load only - ANSWERMaximum Altitude for
APU electrical load only is 35,000 ft.
12 Where is the external APU fire control panel located? - ANSWERAns: in the right
wheel well
42 How else might you think of the standby power off light? - ANSWERAns: it could be
thought of as an essential power warning light
Air Systems - Pressurization: Maximum allowable cabin differential pressure for takeoff
and landing. - ANSWER.125 psi
13 What does A/T LIM annunciation indicate? - ANSWERThe autothrottle is calculating
a degraded N1 limit for the affected engine or engines.
10 What is the normal decrease with flap extension? - ANSWERAns: .4 gal
08 In the standby mode, where is the altitude information derived from? - ANSWERAns:
from the air data computer.
,09 What is the power source for the turbo fan? - ANSWERAns: it is powered by bleed
air
26 When is the Mach trim activated? - ANSWERAns: above Mach .615
11 What problem source is indicated if a generator is showing a fluctuating frequency? -
ANSWERAns: a CSD problem
42 In flight, what would be an indication that the reverse lock had failed and the system
was working properly? - ANSWERAns: the reverser UNLOCKED light would cycle,
indicating the system was constantly detecting the condition and correcting it.
14 What malfunctions does the reset button affect? - ANSWERAns: 1. bleed trip 2. pack
trip 3. duct overheat/pack trip (does not reset a wing body overheat)
19 Where is the CSD oil pressure sensor located? - ANSWERAns: in the inlet line to the
CSD
12 What problem source is indicated by a fluctuating voltage? - ANSWERAns: normally,
a voltage regulator problem; if it is associated with a high amperage, it could be a
system short circuit.
18 What prevents tank surge pressure damage? - ANSWERAns: a system of surge
tanks and vents.
47 What is a more accurate perception of the "Battery Switch"? - ANSWERAns: it may
be more accurately thought of as the "battery bus switch"
07 How may the PMC be bypassed? - ANSWERAns: by turning off the PMC switches
or by an automatic shutdown.
13 When the APU is started, what normal indications are you looking for with respect to
the load meter? - ANSWERAns: the meter will show a slight discharge at first as the air
inlet door opens, then a high discharge as the starter engages.
01 What stages of bleed air do the engines use? - ANSWERAns: Fan, 5th, & 9th
11 What pressure does the engine bleed valve normally limit? - ANSWERAns: it limits
pressure to a maximum of 45 psi.
Wind considerations: Maximum crosswind - ANSWER35 KIAS
42 What powers the trim system? - ANSWERAns: the stabilizer trim is electric/manual,
the ailerons and rudder are hydraulic only
, 15 How would you know that it had automatically shut down? - ANSWERAns: it would
illuminate the master caution, PMC INOP and the ENG annunciator. The engine N1
would also start to drift.
APU: Bleed valve - ANSWERAPU bleed valve must be closed when 1- ground air
connected and isolation valve is open, 2- Engine no. 1 bleed valve is open, 3- isolation
valve and engine no. 2 bleed valves are open
14 When would the PTU become operational? - ANSWERAns: 1. Flaps between 1 and
5 2. A loss of pressure from system B engine driven pump is sensed
32 What technique should you use in discharging a fire bottle? - ANSWERAns: rotate
the handle and hold it until you see the "discharge" light illuminate.
35 If both system "A" and "B" pressure is lost, is there any power source for brake
application? - ANSWERAns: yes, from the brake accumulator
15 If a pack trip occurs during wing anti-ice usage, would you lose wing anti-ice to that
side? - ANSWERAns: no
19 Normally, what does the FAULT light indicate? - ANSWERAns: a valid test or a
failure in both loops of either engine
Airplane General: Maximum Speeds - ANSWERMaximum Speeds: Observe Vmo
pointer and gear/ flap Placards
63 What is the normal voltage range of the TRs? - ANSWERAns: 24 - 30
05 Why are the "A" and "B" system reservoirs pneumatically pressurized? -
ANSWERAns: to prevent foaming of the fluid (causes pump cavitation).
34 If the DC meter switch is placed to the STBY PWR position, what would you be able
to read? (e.g. volts/amps, both) - ANSWERAns: voltage only
13 Assuming a scheduled cruise altitude above 28,000, what differential pressure does
the AUTO controller schedule? - ANSWERAns: 7.8 ±.1 psid
10 Does the PMC offer overspeed or over-temperature protection? - ANSWERAns: yes,
both.
19 When does it operate? - ANSWERAns: at all times except when both packs are
operating and one or both of the packs is in the HI mode, or when fan is manually
turned off.
Flight Controls: Flap setting for takeoff - ANSWERTakeoff flaps may only be 5 or 15
