Engines, Fuel and Electrics Flashcards
What does amber REV above N1 indicate?
Associated reverser not fully stowed (but not fully deployed) Should be < 10 secs, if >10 sec = MC and auto stow
If EGT is in red, what does this mean?
EGT limit has been exceeded
If pre-start there is a red box around the EGT, what does this mean?
On the previous trip there was an exceedance. The box will also show after shutdown
What are the primary engine instruments?
N1, EGT
When does an amber ‘ENG FAIL’ show on the EGT gauge?
<50% N2 and eng start lever (ESL) at idle detent
What will occult a ‘ENG FAIL’ warning?
- ESL to CUTOFF
- Engine recovers >50% N2
- eng fire swx pulled
What does ‘START VALVE OPEN’ on the upper DU mean?
The start valve is open, air can be supplied to the starter. Normal to see up to around 56% N2
Amber ‘ENG CONTROL’ on o’head panel?
- Not dispatchable
- Operates up to 80kts or 30sec after landing.
- Doesn’t illum in the air
If a secondary engine limit is exceeded in flight how is the crew notified?
The blanked lower DU will come up, individual warnings are then displayed on each parameter, either in red, amber or contrast inverted
What are the different modes of the EEC?
- Normal. White ‘ON’ lights illuminated.
- Soft fail. White ON and amber ALTN both illum with high TL position
- Hard fail. White ON and amber ALTN with low TL position
- Hard fail. Only amber ALTN illuminated
Which controls can be used to close the eng fuel shut off valve?
ESL or eng fire swx
During start when should eng start swx move to off?
Around 56% N2. If not automatically the FO can move the switch
During start when should you select the ESL to idle detent?
At 25% N2 (if hot and high N2 may stagnate lower, you can select idle above 20%)
You hear a click at 50% N2 on first start, is this the eng start swx going off early?
No the CVR switch pops from on back to auto at 50% N2 on the start of the first engine, eng start swx is at 56%
Indications of a wet start?
Fuel flow after ESL to idle but no EGT rise. After 15 sec the ac will auto shut off fuel flow.
When does the engine driven alternator provide enough power for self- sustained operation of the engine?
15% N2
What engines does the 737-800 have?
CFM-56
How is thrust produced by the engine?
80% from bypass air, 20% residual jet thrust
How many spools on the engine?
- 2
- N1 (1 x Fan, 3 x compressors, 4 x turbines)
- N2 (9 x compressors, 1 x turbine)
Where is the gearbox driven from?
The N2 spool (hyd pumb, IDG, fuel pump, oil pump, hydromechancal unit, air starter)
Is there any over temp protection on start?
No, protection only kicks in after over temp, must be regulated by crew.
What must you wait for the N2 to decay to before dry cranking?
20% N2
How many channels does each EEC have?
- both channels are compared to a set of look up tables, if one differs from the other and the look up table, it is automatically swapped out of use
Which EEC channel does the engine normally start in?
It swaps between starts and is uncontrollable or monitorable by the crew.
What is the min oil level to start?
12
What does ‘OIL FILTER BYPASS’ mean?
Impending filter bypass, not that it has already bypassed. Follow QRH, scavenger pump filters saturated with contaminent, will need to reduce TL towards closed until caption extinguishes
What indications will you get with ‘LOW OIL PRESSURE’ on engine instruments and when?
10 sec flash on illuminate. The flash is inhibited between 80kts and 400ft but the caption will still come on.
Explain the eng start swx?
GND, air starter valve opened for start
OFF, auto ignition on L AND R igniter during flame out (<50% N2)
CONT, the selected igniter (L OR R) is permanently firing (selected for TO, lngd, heavy rain or icing conditions)
FLT, for in flt starting fires both L AND R igniters
If EGT is likey to exceed during start what is the indication?
A flashing white box around the temp digits
Can you trust the magenta X-BLD caption for relighting?
No, there is a table in the QRH, the X-BLD may illuminate in widmill areas
What is the VIB limit?
4
Can you operate in the amber band of the EGT?
Yes for up to 10 mins, after this it will go red and record an exceedance
If hyd A or B fail with the associated REV deploy?
Yes, but a t reduced speed (circa 50% slower than norma via stby hyd)
What triggers limit REV deployment?
WoW or RALT <10ft must be active to allow REV select
Is there any mechanical linkage to the engines from the throttle for reversionary operation?
No
How many idle settings?
Ground, flight & approach (flaps in land config or eng TAI selected) App idle is the highest to allow quick accel for GA
If the EEC has failed when is approach idle selected?
Below 15000ft, as flap lever and TAI correlation is unavailable without EEC
How can the AC trans BUSs be powered?
Eithe IDG, the APU or gnd power cart
What services are powered from the ground service BUS?
The battery chargers and servicing utilities (on gnd and in the air!)
If IDG 2 fails how can AC trans BUS 2 be powered in flight?
Via both BTBs from AC trans BUS 1 (and IDG1) or via a single BTB from the APU
With only 1 IDG running what load shedding occurs?
None by default, if it can supply the full load it will. First to be shed are the galleys, then the main AC BUSs
If you disconnect an IDG in flt can it be re selected?
No (red covered switches are irreversable in flight)
Normally where does DC BUS 1 receive power from?
TR1 ( but can be powered by TR 2 or 3 also)
BUS TRANS swx OFF, where is the CBTR (cross BUS tie relay)?
Open (both BTBs are also open) isolating the 2 halves of the electric system
BUS TRANS swx AUTO, where is the CBTR?
Closed, until ILS captured, then open to prevent double failure on apprach
When is STBY PWR activated in AUTO?
AC trans BUS 1 and DC BUS 1 lose power
How long does battery stby power last?
60mins if fuly charged (30 mins per batt), main batt will be partly discharged if an internal APU start was done
How are the stby BUSs powered on the ground with no AC?
Battery
What are norm and stby power supplies for the stby AC BUS?
Normal from AC trans BUS 1
Stby from the static inverter from the battery
Can you parallel AC sources (have 2 AC sources on one BUS)?
No
Can you parallel DC sources?
Yes
APU altitude limits?
Electric load only, up to 41000ft
Bleed only, up to 17000ft
Electric and bleed, up to 10000ft
How much fuel does the APU use?
Circa 70kg per hour
If APU is your only AC source in flt, is there any auto load shed?
Yes, the galleys
IDG 1 fails, you have IDG2 & APU providing AC, will there be auto load shed?
No, if the APU is only supplying one AC trans BUS it will keep the galleys
How long does a fully discharged battery take to charge?
Circa 60 mins
At the end of the charge cycle what does the battery charger do?
Runs a test dischsrge on the battery ‘BAT DISCHARGE’ amber if failed
What actually powers the hot bat BUS in flight with no failures?
The battery charger(s), once the bat is charged the chargers supply DC
What have you lost with STBY PWR OFF light?
Loss of power to any of: AC stby BUS, DC stby BUS or Batt BUS
Meaning of blue APU GEN OFF BUS?
APU is available to be on the bus, but isn’t. (different logic to GEN OFF BUS)
Meaning of blue GEN OFF BUS?
1 or 2 IDG is off the BUS, may or may not be in a position to provide power
Batt voltage?
24V (batt charger 22-32 V)
Normal AC?
115V, 3 phase, 400Hz, 90 KVA
Is APU AC different to IDG output?
No, both IDGs and APU have same rating
Where is the air starter mounted, what is it connected to?
Engine aux gear box, connected to N2 shaft
What are the possible sources of power?
- 2 x AC IDGs
- 2 x DC Batteries
- Extrenal AC connection
- AC APU generator
When is the switched hot batt BUS powered?
When the battery is charged and the batt swx is on
Fuel x-feed selected open, caption stays bright blue?
Valve not open. (dim blue would be valve open, bright indicates opposite condition to the caption)
How is a fuel imbalance shown, when,when does is go off?
> 453kgs between main (wing) tanks, amber IMBAL under the lower tank capacity gauge (IMBAL remains until <91kg difference)
What does a fuel amber CONFIG warning mean?
Both ctr pumps off or low pressure, but with >726kgs in ctr tank
Fuel gauging inop, how can you measure contents?
Drip sticks, 6 in each wing, 4 in the ctr tank, 16 total (a fuel gauge inop is dispatchable iaw the MEL CDL!)
What 2 operations are achieved with the manual defueling valve?
Defuelling an transfer?
How can you transfer fuel in the air?
You can’t
How is the refuelling system powered not from the flt deck?
Opening the access door, or by an alternate switch inside the refuel access
Which tank will feed first and why?
The ctr. The pumps are rated to a higher pressure
If all fuel pumps fail is all fuel usable?
No ctr tank can only transfer by pump (remaining fuel is unusable), main tanks will gravity feed to respective engines
Where is fuel temp measured?
Main tank 1 (left wing)
What is and when does the ctr tank fuel scavenge jet pump (FSJP) operate?
When main tank 1 (left wing) fwd pump is on and tank 1 reduces to 50% capacity. Transfers any residual fuel from the ctr tank
When does the Fuel Scavenger Jet Pump stop?
It doesn’t, keeps running until shut down
What are the tank capacities?
3.9 - 13 - 3.9 approx (3915 and 13066 exactly)
If ctr tank has >453kgs limit on main tanks?
They must be full
Max and min fuel temp?
Max 49, min -43 deg C (or 3 deg above fuel freezing point)
Max fuel for landing if you expect ‘non environmental icing’ (hoar frost due to cold fuel after rapid descent)
6000kg
Max difference between calc and metered uplift before you have to do a manual check?
625 liters
Min fuel in a main (wing) tank to swx on the hyd pumps?
760kgs
With a Universal Fault Interrupter fitted how many ctr low pressure lights are required for a MC?
2 (normal boeing logic)
With a Ground Fault Interrupter how many ctr low pressure light required for a MC?
1 (abnormal logic due to ctr tank explosion risk)
Main tanks, how many low pressure lights required for a MC?
2
Do the ctr tank low pressure lights remain on for the whole flight once empty?
No, occulted when pumps swx off (normal ops). Main tank low pressures will stay on with the pumps off
What does the nitrogen generation system (NGS) do?
Generates nitrogen to mix with the air in the ctr tank to inert any fuel vapour
Walk around checks for Nitrogen Generation System?
- Blue or green light = good
- Red or no light = bad (in the main wheel well)
Where does APU get fuel from?
From the left fuel manifold. If no pumps on, will suction feed from the left main tank
Which pumps do you use for the APU?
Some ac have a bespoke automatic fuel pump, but for fleet commonality you have to select a ctr or main 1 fuel pump on before starting the APU
During cruise where is the CTBR?
Closed
What is the meaning of the ENGINE CONTROL lights on the engine panel?
- Aircraft on ground
- eng running
- issue with ECC
- none dispatch
- less 80knts
- 30 sec after land
