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zeke
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C-17 Lightning Strike Loss Of All 4 Enignes

Fri Sep 24, 2010 5:27 am

AW&ST ARES is reporting that a USAF C-17 with 176 refugees onboard lost all engine and most of their electronics after a lightning strike over Pakistan.

The crew were able to restart two engines and make a safe landing.

"An Air Force official confirms the incident occurred, but said details cannot be provided until a safety investigation is complete. "

from "Harrowing C-17 Ride Over Pakistan"

http://www.aviationweek.com/aw/blogs...=blogScript&plckElementId=blogDest

I have seen some nasty damage lightning can do to aircraft, but this one mike take the cake.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
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kc135topboom
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Fri Sep 24, 2010 2:10 pm

It will be interesting to read the safety investigation report on this incident. I wonder if the AC electrical system was fried, taking out all of the fuel pumps, until the DC electrical system could be restored (by swapping the APU battery with the airplane battery). That was a technique we had in the KC-135 in the event of total electrical failure.

Our main fuel tank pumps were AC and/or DC driven.

Does anyone know if the F-118 engines (PW-2040) have a mechanical drive driven engine mounted fuel pump, or is it electrical driven? The J-57 engine (JT-3C) had a mechanical drive fuel pump. Our fuel pumps in the fuel tanks were electrical, but we also had hydraulic driven pumps in the body tanks (but electrically controlled).
 
evil8er2006
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Fri Sep 24, 2010 11:01 pm

Quoting KC135TopBoom (Reply 1):
Does anyone know if the F-118 engines (PW-2040) have a mechanical drive driven engine mounted fuel pump, or is it electrical driven? The J-57 engine (JT-3C) had a mechanical drive fuel pump. Our fuel pumps in the fuel tanks were electrical, but we also had hydraulic driven pumps in the body tanks (but electrically controlled).

The C-17 has two AC-powered fuel boost pumps for each engine that supply it pressurized fuel under normal conditions. However, the engines also have a mechanical pump mounted to the accessory gearbox that can suction-feed fuel to the engine. The engine can still produce max power using suction-feed up to 10,000 ft.
 
donniecs
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Sat Sep 25, 2010 2:42 am

Quoting KC135TopBoom (Reply 1):
I wonder if the AC electrical system was fried, taking out all of the fuel pumps, until the DC electrical system could be restored (by swapping the APU battery with the airplane battery).

I know nothing about the C-17 but most aircraft have quite a bit of DC powered avionics so that everything is split between AC and DC in the event of an issue. Also it is very unlikely to lose an just an entire "AC system" maybe a major bus and some other components or something as there are so many components and separate systems. If it gets to that point you're usually going to lose everything as this C-17 did. Since most (all that I have ever heard of) only run one type of generator and then produce both AC and DC power through converters or transformer rectifiers.

I'd guess with the lose of engines, they were flying on DC battery power until they could get the APU cranked. I'd guess that they would of had at the least the pilots DU/PFD, 1 FMS, and some radios until they got that APU cranked or windmill started the engines.
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UH60FtRucker
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Sat Sep 25, 2010 2:51 am

Bumpy ride through a thunderstorm, with a sudden loss of engine noise and cabin lighting? lol I bet those refugees.... many of which probably had never even been on an airplane... were scared shitless.
Your men have to follow your orders. They don't have to go to your funeral.
 
keesje
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Sat Sep 25, 2010 6:40 am

Quoting KC135TopBoom (Reply 1):
It will be interesting to read the safety investigation report on this incident.

Yes I guess everybody is diving on this. Redundancy is designed into the systems to prevent something like this ever happening. Luckely the crew was able to restart 2 engines and land. Big question why the other two could not be restarted.
"Never mistake motion for action." Ernest Hemingway
 
MD11Engineer
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Sat Sep 25, 2010 8:37 am

The c-17 is powered by a variant of the PW-2000 engine. This engine is FADAC controlled. If not properly bonded (the B757 maintenance manual for the same engine gives precise instructions for this, I assume that the T.O.´s for the C-17 do the same), lightning can damage electronic components inside the FADEC. While the FADEC has two independent channels (read complete computer circuit boards), either of which can control the engine, they both can be fried. Unlike with a mechanical engine like the JT8D, thne engine will be dead if the computer is gone.

Jan
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Galaxy5007
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Sat Sep 25, 2010 5:02 pm

I'm hearing rumors that the tail number is 08-8201...was the newest in the fleet at the time of the incident.
 
evil8er2006
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Sun Sep 26, 2010 9:09 am

Quoting DonnieCS (Reply 3):
I'd guess with the lose of engines, they were flying on DC battery power until they could get the APU cranked. I'd guess that they would of had at the least the pilots DU/PFD, 1 FMS, and some radios until they got that APU cranked or windmill started the engines.

In the event you lose all four engines and their associated generators, the aircraft will be operating on battery power. The C-17 cannot start the APU in flight. So this leaves the pilots with their standby instruments (standby ADI, altimeter, airspeed indicator, and the compass), a backup control unit for the UHF/VHF radios, no HUDs, no MFDs, no BDHIs (RMI w/ DME), and no way of controlling the mission computer (FMS). Losing all four generators will lead to the flight controls being in backup (mechanical) mode. As for getting the engines back, the critical action items involve placing the ignition switch into override mode to get both sets of igniters in each engine firing to allow an immediate airstart and deploying the ram air turbine to provide you with hydraulic power for one of the hydraulic systems. In any case, you have a handful of jet at this point.
 
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kc135topboom
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Sun Sep 26, 2010 1:41 pm

So if the FADEC on the engines was damaged or destroyed how did they get two of them working again?
 
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Moose135
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Mon Sep 27, 2010 3:12 am

Quoting UH60FtRucker (Reply 4):
Bumpy ride through a thunderstorm, with a sudden loss of engine noise and cabin lighting? lol I bet those refugees.... many of which probably had never even been on an airplane... were scared shitless.

I've flown an airplane lots of times - if I had a bumpy ride with a sudden loss of engine noise and cabin lighting, I'd be scared shitless too!
KC-135 - Passing gas and taking names!
 
Galaxy5007
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Mon Sep 27, 2010 8:28 pm

The RAT also provides some electrical power. The primary purpose of the RAT is to generate hydraulic power for the primary flight controls, and send hydraulic power to the RAT emergency generator which is hydraulically driven by the system. Not sure on the C-17, but the C-5s RAT runs system 2. So, if the RAT was working properly, it would have been deployed automatically once 3 of the 4 generators were offline and provided power to the essential components needed to attempt a recovery of the aircraft. The function of the battery on planes are extremely limited. As far as I'm aware, its limited to starting the APU on the C-17. The C-5s battery (which I am familiar with) is only there to provide power to start the APUs.

Quoting KC135TopBoom (Reply 9):
So if the FADEC on the engines was damaged or destroyed how did they get two of them working again?

There is a mechanical back up to operate the inboard engines...I'm curious if those are the two that they got working again or not.
 
evil8er2006
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Mon Sep 27, 2010 9:55 pm

Quoting Galaxy5007 (Reply 11):
The RAT also provides some electrical power. The primary purpose of the RAT is to generate hydraulic power for the primary flight controls, and send hydraulic power to the RAT emergency generator which is hydraulically driven by the system.

The RAT on the C-17 only provides hydraulic power; it provides no electrical power whatsoever. The batteries provide all electrical power when there is no electrical power coming from the engines, APU, or ground power cart. The RAT provides hydraulic power to the #4 hydraulic system, which runs some of the flight controls and the stab trim. The RAT does not extend on its own with the loss of all electrical power/generators. You have to hit the RAT extend switchlight which releases the electric uplock and allows the spring-loaded RAT to deploy.

On the subject of the aircraft's batteries, they do more than just provide power to start the APU. The provide power to the systems I mentioned above in an earlier post. They also provide power for other stuff such as single-point refueling, but I doubt you care about that when you have a four engine flameout situation.
 
Galaxy5007
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Tue Sep 28, 2010 12:04 am

Quoting Galaxy5007 (Reply 11):
Quoting KC135TopBoom (Reply 9):
So if the FADEC on the engines was damaged or destroyed how did they get two of them working again?

There is a mechanical back up to operate the inboard engines...I'm curious if those are the two that they got working again or not.

I should mention I'm no expert on the C-17 systems since I never worked on the jet...

Quoting evil8er2006 (Reply 12):
The RAT on the C-17 only provides hydraulic power; it provides no electrical power whatsoever. The batteries provide all electrical power when there is no electrical power coming from the engines, APU, or ground power cart. The RAT provides hydraulic power to the #4 hydraulic system, which runs some of the flight controls and the stab trim. The RAT does not extend on its own with the loss of all electrical power/generators. You have to hit the RAT extend switchlight which releases the electric uplock and allows the spring-loaded RAT to deploy.

On the subject of the aircraft's batteries, they do more than just provide power to start the APU. The provide power to the systems I mentioned above in an earlier post. They also provide power for other stuff such as single-point refueling, but I doubt you care about that when you have a four engine flameout situation.

I have to say, I was pretty much totally wrong here...I have to slap myself in the face for my post. On the up side, my FCC friend stationed at KDOV told me two things. The APU can be started in flight for one, although usually doing this involves replacing an inlet door when it hits the deck. Also, the RAT does in fact autodeploy when no hydraulic power is being produced in flight. How it works, I would have to read the T.O. to understand it...and I don't exactly have one in front of me. So I'll be a good boy and drop out of the discussion, lol
 
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kc135topboom
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Tue Sep 28, 2010 12:15 pm

So, if the APU can be run inflight, I assume they started it? Also, the battery does not power the DC Buss?
 
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zeke
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Tue Sep 28, 2010 4:11 pm

Quoting KC135TopBoom (Reply 1):

Does anyone know if the F-118 engines (PW-2040) have a mechanical drive driven engine mounted fuel pump, or is it electrical driven?

The LP and HP engine fuel pumps are not electrically driven.

Quoting evil8er2006 (Reply 2):

Thanks for your contribution, I have reviewed the C-17 manuals, what you have posted is 100% in correlation with the C-17 manuals.

Quoting MD11Engineer (Reply 6):
This engine is FADAC controlled.

Actually 2xEEC, not as advanced as a FADEC, but self powered above 10% N1.

Quoting KC135TopBoom (Reply 9):
So if the FADEC on the engines was damaged or destroyed how did they get two of them working again?

The have a checklist for 4 engine restart, it involved an inflight restart using forward speed to accelerate the engines to start. No APU is used as part of the checklist.

Quoting KC135TopBoom (Reply 14):
So, if the APU can be run inflight, I assume they started it?

Not according to the C-17 manual, on ground only, and may not be enough at hot and high airports.

Quoting KC135TopBoom (Reply 14):
Also, the battery does not power the DC Buss?

According to the C-17 manual, batteries power the BATT DIR BUSS and the BATTERY BUS, the 4 DC BUSS (DC BUS 1 etc) are power off the TR1 etc.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
MD11Engineer
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Tue Sep 28, 2010 5:55 pm

Quoting Zeke (Reply 15):
Quoting MD11Engineer (Reply 6):
This engine is FADAC controlled.

Actually 2xEEC, not as advanced as a FADEC, but self powered above 10% N1.

They are operating digitally and are full authority. There is no mechanical backup as on the CFM56-3 (EEC and MEC).
All engine functions (fuel control, stall management and efficiency control e.g. turbine case cooling), are handled by the two EEC channels (actually two similar computer circuit boards), of which there is always one in control and the other one a hot standby.
There is, except for the fuel cutoff switch and high pressure shutoff valve, no means of interference by the pilot. The pilot requests a certain thrust through the thrust levers, the thrust lever movement gets converted into an electrical signal by the thrust lever angle resolvers (two, one for each channel). The EEC channel in command receives this signal and controls all engine functions to deliver the required thrust (in form of an EPR, while obeying engine limitations).

Both EEC channels receive their power from a small alternator mounted on the engine gearbox, which delivers enough power to run all functions when N2 is at least 8%.
For ground testing purposes it is possible to power the EECs via a ground test power switch (at least on the B757, I assume that the C-17 is similar).

Jan
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kc135topboom
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RE: C-17 Lightning Strike Loss Of All 4 Enignes

Wed Sep 29, 2010 11:52 am

Quoting Zeke (Reply 15):
Zeke
Quoting MD11Engineer (Reply 16):
MD11Engineer

Thanks to both of you.

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