DCS F-18 - Emergency of the Day

[VBF-12 Gosling]

To make finding and reading the emergencies easier they are all here grouped into Warnings, Cautions and Advisories, in alphabetical order, not including the L or R side letter; see BLEED.

Please don’t post anything else here. If you have questions make a separate post please.

Warnings

APU FIRE	L BLEED & R BLEED	L BLEED or R BLEED	FIRE
HOOK	LDG GEAR Light	L BAR	LAW Light

Cautions - display on the DDI ‘over’ the FCS page (the boxes page)

AIR DATA	L AMAD R AMAD	L AMAD PR R AMAD PR	ANTI SKID
AOA DEGD	APU ACCUM APU ACC	ASPJ AMP	ASPJ DEGD
ASPJ HI B	ASPJ LO B	ASPJ OVRHT & ASPJ OH	ASPJ RPTF
L ATS R ATS	AUTO PILOT	AV AIR DGD	AV AIR HOT
E BATT LO or U BATT LO	BATT SW & BATT SW	BINGO & ”Bingo, Bingo”	L BLD OFF &/or R BLD OFF
L BOOST LO &/or R BOOST LO	BRK ACCUM	CANOPY	CAUT DEGD
CG	CK FLAPS	CHECK SEAT & CK SEAT	CHECK TRIM
CK ECS	CNI	DFIR OVRHT	DFIR GONE
DL OVRHT	DTR1 COLD &/or DTR2 COLD	DTR1 SHTDN &/or DTR2 SHTDN	L DUCT DR &/or R DUCT DR
DUMP OPEN	L EGT HIGH &/or R EGT HIGH	ERASE FAIL	EXT TANK
EXT XFER	L FLAMEOUT &/or R FLAMEOUT & “Engine Left (Right), Engine Left (Right)”	FLIR OVRHT	L FUEL HOT &/or R FUEL HOT
Fuel LO & Fuel LO & “Fuel Low, Fuel Low”	FUEL XFER	L GEN &/or R GEN & L GEN &/or R GEN	G-LIM 7.5G & “Flight Controls, Flight Controls”
G-LIM OVRD	GPS DEGD	GUN GAS	HAND CTRL
HOME FUEL	IFF 4 & “Mode 4 reply, Mode 4 reply”	IFFAI	IFF OVRHT
L IN TEMP &/or R IN TEMP & “Engine Left (Right), Engine Left (Right)”	INLET ICE	INS ATT	INS DEGD
INS VEL	LADDER	MC 1	MC 2
MC CONFIG	MDL LOAD	MIDS OVRHT	MU LOAD
NAV FAIL	NAV HVEL	NAV VVEL	NFLR OVRHT
OBOGS DEGD	OCS	L OIL PR &/or R OIL PR & “Engine Left (Right), Engine Left (Right)”	L OVRSPD &/or R OVRSPD & “Engine Left (Right), Engine Left (Right)”
OXY LOW	PARK BRAKE	L PITOT HT &/or R PITOT HT	POS/ADC
PROBE UNLK	RACK UNCPL	R-LIM OFF	FIRE EXTGH & READY
S/W CONFIG	L STALL &/or R STALL & “Engine Left (Right), Engine Left (Right)”	TANK PRESS	TK PRES LO
TK PRES HI	VEL	VOICE/AUR	WDSHLD HOT
WING UNLK	-	-	-

Left WCA Panel

		GO	NO GO
FIRE	MASTER CAUTION	L BLEED SPD BRK	R BLEED STBY
		L BAR	REC
		L BAR	XMIT
			ASPJ OH

Right WCA Panel

RCDR ON	DISP
—— ——	—— ——	APU FIRE	FIRE
——	SAM
AI	AAA
CW

Annunciator Panel

CK SEAT	APU ACC	BATT SW
FCS HOT	GEN TIE	——
FUEL LO	FCES	——
L GEN	R GEN	——

Other Cautions
CABIN - On Cabin Pressurisation Guage
HOOK - Above Hook Operating Handle

EMERGENCY PROCEDURES[/u]

CH 13 - Ground Emergency Procedures Link
CH 14 - Takeoff Emergency Procedures Link
CH 15 - In-flight Emergency Procedures Link
CH 16 - Landing Emergency Procedures Link
CH 17 - Ejection Emergency Procedures Link


DCS F-18C Failures Known Failures

Having looked at the Mission Editor this is a list of the possible failures. I will be trying to link them in Green to the Associated Cautions and Warnings which will then be in bold above:

1. Utility Battery Failure
2. Emergency Battery Failure
3. Left Generator Failure
4. Right Generator Failure
5. Left Transformer-Rectifier Failure [/font] [/a]
6. Right Transformer-Rectifier Failure [/font] [/a]
7. Hyd 1A Leakage [/font] [/a]
8. Hyd 1B Leakage [/font] [/a]
9. Hyd 2A Leakage [/font] [/a]
10. Hyd 2B Leakage [/font] [/a]
11. Isolated Hyd 2B System Leakage [/font] [/a]
12. Left Engine: Main Fuel Flow Control System Failure [/font] [/a]
13. Right Engine: Main Fuel Flow Control System Failure [/font] [/a]
14. Left Engine: AB Fuel Flow Control System Failure [/font] [/a]
15. Right Engine: AB Fuel Flow Control System Failure [/font] [/a]
16. Left Engine: Nozzle Control System Failure [/font] [/a]
17. Right Engine: Nozzle Control System Failure [/font] [/a]
18. Left Engine: Oil Leakage
19. Right Engine: Oil Leakage
20. Left Power Turbine Shaft Failure
21. Right Power Turbine Shaft Failure
22. Left AMAD: Oil Leakage
23. Right AMAD: Oil Leakage
24. Left Boost Pump Failure
25. Right Boost Pump Failure
26. Tank 1 Transfer Failure
27. Tank 4 Transfer Failure
28. External Left Wing Tank Transfer Failure
29. External Right Wing Tank Transfer Failure
30. External Centreline Tank Transfer Failure
31. Fuel Quantity Gauging System Failure [/font] [/a]
32. WOW System Failure [/font] [/a]
33. NWS Failure [/font] [/font] [/a]
34. ECS Valve Failure [/font] [/a]
35. OBOGS Failure
36. LEF Failure [/font] [/a]
37. Aileron Failure [/font] [/a]
38. FCS Channel 1 Failure [/font] [/a]
39. FCS Channel 2 Failure [/font] [/a]
40. FCS Channel 3 Failure [/font] [/a]
41. FCS Channel 4 Failure [/font] [/a]
42. Air Data Compter Failure
43. MC1 Failure
44. MC2 Failure
45. Left Pitot Heater Failure
46. Right Pitot Heater Failure

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 1 - APU Fire Warning

APU FIRE

Audio = “APU Fire, APU Fire”

IN FLIGHT or ON GROUND
* 1. APU FIRE light ... ... ... ... ... ... ... PUSH
* 2. FIRE EXTGH READY light . ... ... ... PUSH

GROUND
* 3. Throttles ... ... ... ... ... ... ... ... ... OFF
- 4. Egress

Quick Memory:
PUSH / PUSH / OFF

Notes:
On the ground with Weight on Wheels the APU FIRE extinguishing system operates automatically with a 10sec delay between arming and firing the extinguisher bottle. 28Vdc is require, hence leaving the battery ON.
With weight off wheels the system is manual as above.

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 2 - Dual LEFT & RIGHT BLEED

L BLEED

&

R BLEED

AUDIO - “Bleed Air Left / Bleed Air Left” and “Bleed Air Right / Bleed Air Right”

GROUND
1. Throttles .. ... ... ... ... ... ... ... ... ... ... ... OFF

IN FLIGHT
* 1. Throttles ... ... ... ... ... ... ... ... ... ... ... Minimum practical
* 2. Emergency oxygen green ring(s) .. ... ... PULL - Can’t find these!!!
* 3. BLEED AIR knob .. .. ... ... ... ... ... ... ... OFF (DO NO CYCLE)
* 4. Initiate rapid descent to below 10,00 feet cabin altitude
If Dual BLEED warning lights go out, execute DUAL BLD OFF caution procedure.

If lights remain on -
- 5. Land as soon as possible.
- 6. Airspeed ... ... ... ... ... ... Maintain below 325 Kts (300 to 325 Kts optimum)
- 7. ECS MODE switch ... ... ... OFF/RAM
- 8. AV COOL switch . ... ... ... EMERG
- 9. CABIN PRESS switch ... ... RAM/DUMP
- 10. HOOK handle ... ... ... ... DOWN
- 11. EXT TANKS switch(es) ... STOP
- 12. OXY FLOW knob(s) ... ... OFF
- 13. OBOGS control switch ... OFF
- 14. Maintain altitude below 10,000 feet MSL prior to emergency oxygen depletion (10 to 20 minutes)
- 15. Consider removing mask and resetting emergency oxygen system once below 10,000 feet MSL

If AV AIR HOT caution appears -
- 16. Non-essential avionic equipment ... ... ... OFF (e.g., RADAR, UFC controlled avionics, ECM, sensors, MC2)

Quick memory:
MIN / PULL - Can’t find these!!! / OFF / DESCEND / LASAPos

* = Immediate Acrions
OBOGS - Onboard Oxygen Generation System (Back Left)
Italics - Not implemented

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 3 - Single LEFT or RIGHT BLEED Warning

L BLEED

or

R BLEED

AUDIO - “Bleed Air Left / Bleed Air Left” or “Bleed Air Right / Bleed Air Right”

GROUND
1. Throttles .. ... ... ... ... ... ... ... ... ... ... ... OFF

IN FLIGHT
* 1. Throttle affected engine ... ... ... ... ... ... ... IDLE
* 2. BLEED AIR knob .. .. ... ... ... ... ... ... ... L OFF or R OFF (DO NO CYCLE)

If light goes out, execute single L BLD OFF or R BLD OFF caution procedure.


If light still on, do the following in order until light goes out -
* 3. Throttle affected engine ... ... ... ... ... ... ... OFF
* 4. Emergency oxygen green ring(s) ... ... ... PULL - Can’t find these!!!
* 5. BLEED AIR knob ... ... ... ... ... ... ... ... ... OFF (DO NOT CYCLE)
* 6. Initiate rapid descent to below 10,00 feet cabin altitude
- 7. Land as soon as possible.

If both bleeds secured -
- 1. Airspeed ... ... ... ... ... ... Maintain below 325 Kts (300 to 325 Kts optimum)
- 2. ECS MODE switch ... ... ... OFF/RAM
- 3. AV COOL switch . ... ... ... EMERG
- 4. CABIN PRESS switch ... ... RAM/DUMP
- 5. EXT TANKS switch(es) ... STOP
- 6. OXY FLOW knob(s) ... ... OFF
- 7. OBOGS control switch ... OFF
- 8. Maintain altitude below 10,000 feet MSL prior to emergency oxygen depletion (10 to 20 minutes)
- 9. Consider removing mask and resetting emergency oxygen system once below 10,000 feet MSL

If AV AIR HOT caution appears -
- 10. Non-essential avionic equipment ... ... ... OFF (e.g., RADAR, UFC controlled avionics, ECM, sensors, MC2)

Quick memory:
IDLE / L or R OFF / L or R BLEED ? / OFF / PULL / OFF / DESCEND / LASAPos

* = Immediate Actions
OBOGS - Onboard Oxygen Generation System (Back Left)

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 4 - Engine Fire Warning

FIRE

AUDIO - “ENGINE FIRE LEFT / ENGINE FIRE LEFT” or “RIGHT”

GROUND
* 1. Throttles ... ... ... ... ... ... ... ... ... ... ... OFF
* 2. FIRE light affected engine ... ... ... ... PUSH
* 3. FIRE EXTGH READY light ... ... ... ... PUSH
- 4. BATT switch ... ... ... ... ... ... ... ... ... ... OFF
- 5. Egress.

IN FLIGHT
Dual FIRE Lights -
* 1. Throttles ... ... ... ... ... ... ... ... Minimum practical
Single FIRE light or Dual when side confirmed -
* 2. Throttle affected engine ... ... ... OFF
* 3. FIRE light affected engine .. ... ... PUSH
* 4. FIRE EXTGH READY light .. ... ... PUSH
* 5. HOOK handle .. ... ... ... ... ... ... DOWN
- 6. Land as soon as possible.

* = Immediate actions

Quick memory:
OFF / FIRE ? / PUSH / PUSH / DOWN / LASAPos

Causes

• Fire/overheat condition in corresponding engine/AMAD bay.

Remarks
The probability of extinguishing a fire and preventing delights is greatly increased by immediately discharging the fire extinguisher.

Notes
15.1 ENGINE FIRE IN FLIGHT
See FIRE light in the Warning/Caution/Advisory Displays. If an engine fire is indicated by a FIRE warning light, throttle affected engine OFF. A fire may be confirmed if the FIRE warning light stays on with the throttle OFF, or the light goes off and the system checks bad. For dual FIRE light cases where the pilot is unable to discern which fire light came on first, throttle left and right engine to as low as practical forflight and check engine instruments for engine condition. Once affected engine is determined, throttle affected engine OFF. Prior indications of high fuel flow, high EGT, rough running, or smoke and fumes may also confirm a fire. If engine stall is indicated, immediately place the throttle to OFF. Do not press the FIRE light again, as this will reopen the fuel shutoff valve. With an engine fire, lower hook as soon as possible. Excessive heat on hook release cable may make it impossible to lower the hook.

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 5 - HOOK Warning

HOOK

IN FLIGHT
1. Reduce airspeed.
If HOOK light remains on -
2. Get a visual inspection (if practical).
If the Hook is in the up position -
3. HOOK circuit breaker ... ... ... ... ... PULL
If the HOOK light remains and the hook is partially extended -
4. Throttle right engine ... ... ... ... ... ... IDLE for one minute then OFF
5. Reduce airspeed to drop Hyd2 pressure to zero (if practical).
6. Restart for landing.
If hook still fails to extend (CV landing) -
7. Divert.
If the hook is partially extended -
8. Attempt a normal carrier landing.

Quick memory:
Reduce / Inspect / PULL / IDLE / Zero / Restart / Divert / Normal CV Landing

Cause:

• Arrester hook position does not agree with HOOK handle position.
  
• Hook not fully extended with HOOK handle down in flight.
• Hook down with Weight on Wheels
  

Remarks
If the mechcanical hook uplatch mechanism fails, tje hook cannot be released and an arrested landing is not possible. If the hook is unlocked (HOOK handle down) but fails to leave th up position, an arresting hook system failure may be applying Hyd2B pressure to hold the hook up. For this reason, pulling the HOOK circuit breaker deenergises the hook selector valve and ensures HYD 2B pressue is removed.

If the arresting hook is not properly charged, the arresting hook may not fully extend due to airloads and Hyd2B back-pressure. In this case, if reducing airspeed does not extinguish the HOOK light, shutting down the right engine reduces Hyd2B back-pressure and should increase arresting hook extension. After engine restart, the hook may retract at a maximum rate of 2 degrees a minute. If the hook light remains on after this procedure and a visual inspection confirms that the hook is partially extended, a successful arrest net in possible due to g-loads at landing.

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 6 - Landing Gear Warning

Light in LDG GEAR Handle

STEADY
1. Check gear down indications
2. Refer to appropriate emergency procedure

• LDG Gear Fails to Retract
• Landing gear unsafe
• Planing Link Failure

FLASHING (Wheels Warning)
1. LDG GEAR handle ... ... ... DN or increase airspeed and/or altitude.

Causes

STEADY

• Landing gear in transit
• Landing gear unsafe
• Planing link failure

FLASHING

• Wheels warning (less than 7,500 feet, less than 175kts, over 250fpm descent rate).t
• Loss of air data.

Notes
14.6 LANDING GEAR FAILS TO RETRACT
If LDG GEAR handle cannot be moved from the DN position -
1. LDG GEAR handle ... ... ... LEAVE DN (DO NOT USE OVERRIDE)
Note: May be an indication of a WOW system failure, Refer to WOW System Failure for additional system effects.

If landing gear warning light and warning tone on with the LDG GEAR handle UP -
1. LG circuit breaker ... ... ... ... CHECK IN
2. LDG GEAR handle ... ... ... DN (DO NOT CYCLE)

If three down and locked indications -
3. Land as soon as practical
4. Consider an arrested landing (Normal braking and NWS may not be available).

If any gear indications unsafe -
3. Refer to Landing Gear Unsafe/Fails to Extend procedure.

PS Links to be added....

Also, getting back on deck is possible....

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 7 - Launch Bar Warning
H

L BAR

ON DECK
1. Suspend catapult launch.
2. LAUNCH BAR switch ... ... ... ... ... ... RETRACT
If launch bar fails to retract -
3. LB circuit breaker ... ... ... ... ... ... ... ... PULL

IN FLIGHT
1. LDG GEAR handle ... ... ... ... ... ... ... ... LEAVE DN (if practical)
2. LAUNCH BAR switch ... ... ... ... ... ... ... VERIFY RETRACT
3. LB circuit breaker ... ... ... ... ... ... ... ... PULL
Carrier -
4. Divert or remove cross deck pendants 1 and 4 (1 and 3 as appropriate) and make a normal landing . Refer to Landing Gear Malfunction Landing Guide.

Causes
ON DECK

• Launch bar control malfunction (proximity switch failure).
• If launch bar is down, NWS will disengage.

IN FLIGHT

• Launch bar failled to retract after catapult launch (Launch bar not up and locked AND weight off the left main gear).
• launch bar control system malfunction (proximity switch failure).
• With the launch bar down, to engage NWS low gain, push and hold NWS button.
  

Remarks
If the red L BAR light remain on, assume that the launch bar is NOT up and locked and that it may drop to the deck during landing. The nose landing gear cannot be retracted. Placing the LDG GEAR handle UP raises teh main landing gear and leaves the nose landing gear extended.

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 8 - Radar Low Altitude Warning

LAW Light on RALT gauge

AUDIO - “Whoop, Whoop” tone

1. Climb above primary RALT setting or reset LAW height to a lower altitude.

Causes

• Aircraft is below the primary low altitude warning (LAW) setting.

Remarks
The audio tone can be cancelled by pressing the button beside :RALT on the UFC.

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 9 - Air Data DDI Caution

AIR DATA on DDI

GROUND
1. Do not takeoff.

IN FLIGHT
1. Maintain subsonic airspeed.
2. Land as soon as practical.

Causes

• MC cannot determine which source error correction (SEC) to command or ADC SEC disagrees with MC commanded SEC.

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 10 - L AMAD or R AMAD on DDI Caution

L AMAD or R AMAD on DDI

IN FLIGHT
1. Throttle affected engine ... ... ... ... ... ... ... IDLE
2. INTR WING switch ... ... ... ... ... ... ... ... ... NORM
If accompanied by BOOST LO caution or GEN caution and more than 5 minutes to landing -
3. Throttle affected engine ... ... ... ... ... ... ... OFF
If more than 5 minutes to landing and no accompanied cautions -
3. Throttle affected engine ... ... ... ... ... ... ... OFF )if practical)
In both cases =
4. Restart for landing (if practical)
5. Land as soon as practical.

GROUND
6. Throttle affected engine ... ... ... ... ... ... ... OFF (When practical)


Causes

• Designated AMAD oil temperature high.
• May indicate a fuselage fuel leak.
• May be caused by an overserviced AMAD, AMAD heat exchanger failure, hot fuel recirculating on system failure or motive flow system failure. Low altitude flight on a hot day with less than 4,000 pounds fuel may cause an AMAD caution. A climb to cooler air may reduce AMAD oil temperature. An empty feed tank or BOOST LO caution will cause loss of AMAD cooling. Continued operation with an AMAD caution may cause loss of the assocaited generator.

Remarks
During ground operation after flight, an AMAD caution may occur due to lack of ram air cooling and low fuel state. Below 1,000 pounds fuel remaining ad above 30 degrees C, an AMAD caution will appear almost immediately. Above 3,000 pounds of fuel remaining and below 30 degrees C, an AMAD caution should not occur. Between these conditions, the time before an AMAD caution will appear is a function of fuel state and ambient temperature (15 minutes at 24 degrees C and 2,000 pounds fuel). Lower fuel quantities and higher ambient temperatures will reduce the time before an AMAD cautions will appear. Shutting down an engine (left engine shutdown preferred) will extend the ground operating time. If the AMAD caution appears, shut down the associated engine.
WARNING
Prolonged operation of a hot AMAD may result in an engine / AMAD bay fire.

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 11 - L AMAD PR or R AMAD PR on DDI Caution

L AMAD PR or R AMAD PR on DDI

1. GEN switch affected engine ... ... ... ... ... ... OFF
If more than 5 minutes to landing -
2. Throttle affected engine ... ... ... ... ... ... ... OFF
3. Consider restart for landing.
4. Land as soon as practical.
If restarting affected engine for landing -
5. GEN switch affected engine ... ... ... ... ... ... OFF
6. Affected engine ... ... ... ... ... ... ... ... ... ... Restart
After engine restarted -
7. GEN switch affected engine ... ... ... ... ... ... OFF

Causes

• Loss of designated AMAD oil pressure.

Remarks
Securing the GEN (ac output) greatly reduces the heat load imparted to the AMAD oil and may prevent heat-related damage to the generator.
WARNING
A L/R AMAD PR caution could be an indication of an AMAD oil leak which may result in an engine / AMAD bay fire.

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 12 - ANTI SKID on DDI Caution

ANTI SKID on DDI

GROUND
1. ANTI SKID switch ... ... ... ... ... ... OFF

IN FLIGHT
If more than 30 seconds to landing -
1. ANTI SKID switch ... ... ... ... ... ... CYCLE ONCE
If caution reappears of if less than 30 seconds to landing -
2. ANTI SKID switch ... ... ... ... ... ... OFF (DO NOT CYCLE)
3. Consider short field arrest net.
4. If arresting gear not available or not desired, regulate brake pedal force to prevent wheel skid.

Causes

• Anti-skid system failed BIT. Anti-skid protection not available for use with normal braking.

WARNING

• Use of brakes without anti-skid at high speed can result in blown tires resulting in loss of directional control. If practical, rollout speed should be as slow as possible before applying brake pedal pressure.
• Do not cycle the ANTI SKiD switch in response to an ANTI Skid caution immediately prior to landing for the following:
  a. The ANTI SKID caution is removed for up to 13.5 seconds as teh system performs IBIT even though the anti-skid system may still be failed.
  Bb, If teh system is not failed, wheel motion at touchdown or during landing rollout may cause a false BIT failure and a dump of normal brake pressure when brakes are applied.
  
• If the ANTI SKID switch is not placed OFF with an ANTI SKID caution displayed, normal braking capability may be lost completely.

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 13 - AOA DEGD on DDI Caution

AOA DEGD on DDI

Carrier -
1. Notify LSO approach light indications may be inaccurate.

Causes

• A single AOA probe is selected. AOA indexers may be inaccurate.

[VBF-12 Gosling]

DCS F-18 - Emergency of the Day 14 - APU ACCUM on DDI Caution

APU ACCUM on DDI and APU ACC on the Annunciation Panel

If APU ACCUM caution appeared following emergency gear or probe extension -
1. HYD ISOL switch ... ... ... ... ... ... ORIDE (until 10 seconds after APU ACCUM caution removed - approximately 20 seconds)
Otherwise, if required or desired -
1. HYD ISOL switch ... ... ... ... ... ... ORIDE (10 seconds maximum)
If caution remains or returns -
2. Do not select HYD ISOL ORIDE.
(To inhibit leaking out HYD 2B.)
3. Extend landing gear as soon as practical.

Causes

• APU accumulator pressure low
• Possible leak in isolated HYD 2B system

Remarks
The APU ACCUM caution can be expected after APU start or after emergency gear / probe extension in flight. With WonW, the APU accumulator recharges automatically. With WoffW, teh HYD ISOL switch may need to be held for up to 10 seconds following emergency gear / probe extension to remove the APU ACCUM caution and 20 seconds to provide a full charge (up to 40 seconds following in flight APU start).
CAUTION
If the APU ACCUM caution appears in flight and is not related to emergency gear / probe extension or APU start, it may indicate a possible leak in the isolated HYD 2B system.