3 Engine Ferry Kit 747
Thread Starter
Nexialist
Joined: Jul 2003
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From: Milton Keynes
3 Engine Ferry Kit 747
Saw a mention of a 3 engine ferry kit for the B747 in the BA747 diverts to MAN thread, I didn't want to add to the confusion there as was wondering what it consitsted of? Is it the same as the kit for 5th engine ferry, or is it a bit more complex?
Joined: Jan 2003
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From: Manchester
To three engine ferry a RB211 you have to remove the fan blades and fit a fairing over the core intake. It is proberbly much the same proceedure on the CF-6 and JT-9.
You can also ferry a JT-9 with the fan blades "Gagged". In this proceedure you tie the fan blades to the stators behind it. The approved tool for this looks like a very long passenger seat belt compleate with the buckle assembly!. I have seen "Shock, Horror" report of this in the "Gutter press" . You know the thing "Aircrafts engine held together with seat belts". But it is an approved M.M. proceedure for the JT-9 . The other thing with this method of ferrying is you have to gag the core to prevent it windmilling. This is done buy removing the hydralic pump and fitting a gag to the pump drive.
A "5th pod" is a whole different ball game!. The fan is removed and the core fairing is fitted in the same way, then a small pylon is fitted to the top of the engine and it is slung under the inboard wing. I have been involved with a 5th pod in my time and it is a long involved and expensive way of recovering an aircraft. I can see why airlines try anything to avoid doing one!. Eaven with the offer on hot and cold running over time I would not want to be involved with one again!!!.
Rgds Dr.I.
You can also ferry a JT-9 with the fan blades "Gagged". In this proceedure you tie the fan blades to the stators behind it. The approved tool for this looks like a very long passenger seat belt compleate with the buckle assembly!. I have seen "Shock, Horror" report of this in the "Gutter press" . You know the thing "Aircrafts engine held together with seat belts". But it is an approved M.M. proceedure for the JT-9 . The other thing with this method of ferrying is you have to gag the core to prevent it windmilling. This is done buy removing the hydralic pump and fitting a gag to the pump drive.
A "5th pod" is a whole different ball game!. The fan is removed and the core fairing is fitted in the same way, then a small pylon is fitted to the top of the engine and it is slung under the inboard wing. I have been involved with a 5th pod in my time and it is a long involved and expensive way of recovering an aircraft. I can see why airlines try anything to avoid doing one!. Eaven with the offer on hot and cold running over time I would not want to be involved with one again!!!.
Rgds Dr.I.
Thread Starter
Nexialist
Joined: Jul 2003
Posts: 182
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From: Milton Keynes
Just shows you how you can get the wrong end of the stick doesn't it? Previously I would have thought the 5th engine ferry would be easier (bolt it up there mate - and limited to 0.81M), and a 3 engine would require a lot of hmmmm blank of this take off that, diconnect the other.
Thanks very much for your time.
Thanks very much for your time.
Joined: Jan 2000
Posts: 347
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From: sussex
There's a bit more to a three engine ferry than just securing the dead engine, jumping in and blasting off on three engines instead of four !
One big concern is a failure of one of the three good engines on take-off - particularly on the same side as the dead engine so the take-off performance calculations have to be very carefully calculated. (A fairly modest cross wind can make the ferry flight a non-starter)
The crew have to be specially trained and current on three engine technique and the flight has to be authorised by the CAA - there are several airfields in the USA which prohibit Three engine ferries 'cos they don't want their nearby towns wiped out if things go wrong !
The special technique is required due to the need to start the take-off using only the two symmetical engines - otherwise the assymmetric thrust will throw the aircraft sideways off the runway. The power of the assymmetric engine is gradually increased until airspeed and therefore rudder effectiveness, can compensate for the yaw.
If it's done too soon or clumsily you're off the runway, if you leave it too late, you don't get airbourne. If it is done in the RAF they probably give the crew an AFC each !!
One big concern is a failure of one of the three good engines on take-off - particularly on the same side as the dead engine so the take-off performance calculations have to be very carefully calculated. (A fairly modest cross wind can make the ferry flight a non-starter)
The crew have to be specially trained and current on three engine technique and the flight has to be authorised by the CAA - there are several airfields in the USA which prohibit Three engine ferries 'cos they don't want their nearby towns wiped out if things go wrong !
The special technique is required due to the need to start the take-off using only the two symmetical engines - otherwise the assymmetric thrust will throw the aircraft sideways off the runway. The power of the assymmetric engine is gradually increased until airspeed and therefore rudder effectiveness, can compensate for the yaw.
If it's done too soon or clumsily you're off the runway, if you leave it too late, you don't get airbourne. If it is done in the RAF they probably give the crew an AFC each !!
Joined: Jan 2000
Posts: 347
Likes: 0
From: sussex
There's a bit more to a three engine ferry than just securing the dead engine, jumping in and blasting off on three engines instead of four !
One big concern is a failure of one of the three good engines on take-off - particularly on the same side as the dead engine so the take-off performance calculations have to be very carefully calculated. (A fairly modest cross wind can make the ferry flight a non-starter)
The crew have to be specially trained and current on three engine technique and the flight has to be authorised by the CAA - there are several airfields in the USA which prohibit Three engine ferries 'cos they don't want their nearby towns wiped out if things go wrong !
The special technique is required due to the need to start the take-off using only the two symmetical engines - otherwise the assymmetric thrust will throw the aircraft sideways off the runway. The power of the assymmetric engine is gradually increased until airspeed and therefore rudder effectiveness, can compensate for the yaw.
If it's done too soon or clumsily you're off the runway, if you leave it too late, you don't get airbourne. If it is done in the RAF they probably give the crew an AFC each !!
One big concern is a failure of one of the three good engines on take-off - particularly on the same side as the dead engine so the take-off performance calculations have to be very carefully calculated. (A fairly modest cross wind can make the ferry flight a non-starter)
The crew have to be specially trained and current on three engine technique and the flight has to be authorised by the CAA - there are several airfields in the USA which prohibit Three engine ferries 'cos they don't want their nearby towns wiped out if things go wrong !
The special technique is required due to the need to start the take-off using only the two symmetical engines - otherwise the assymmetric thrust will throw the aircraft sideways off the runway. The power of the assymmetric engine is gradually increased until airspeed and therefore rudder effectiveness, can compensate for the yaw.
If it's done too soon or clumsily you're off the runway, if you leave it too late, you don't get airbourne. If it is done in the RAF they probably give the crew an AFC each !!
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From: Manchester
Joined: Dec 1998
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From: .
Joined: Feb 2003
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From: USA
I've been involved in 2 engine ferries on tri-jets. Not so bad if its the tail out of action.
Another reason companies don't like ferry flights is the max power take off reduces the life of the other 3 good engines. Balanced against the cost of chartering a freighter ...
Another reason companies don't like ferry flights is the max power take off reduces the life of the other 3 good engines. Balanced against the cost of chartering a freighter ...
Joined: May 2002
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From: somewhere near an airport
one reason 5 pod are not used by all operators is that not all B747 are fitted with the mount points inboard of #2 eng
hanging a 5 pod takes under 2 hrs and removing takes slightly less.
having been involved in several this must cheaper as "donor" aircraft can continue as a normal revenue flt albeit with slightly extra fuel burn and restricted flt speed.if your organised then knock down dollys for dead and new eng come in cargo hold of 5th poded a/c in standard cargo bins with tooling etc
in all have received,unhung,rehung new and dead eng back on aog a/c the 5 pod and dispatched in less than 15 hrs (jt9)believe that a cf6 would be quicker due not having to r/r the cascade vanes which you have to swop on jt9
don't see it very often but fun was had whilst doing them
hanging a 5 pod takes under 2 hrs and removing takes slightly less.
having been involved in several this must cheaper as "donor" aircraft can continue as a normal revenue flt albeit with slightly extra fuel burn and restricted flt speed.if your organised then knock down dollys for dead and new eng come in cargo hold of 5th poded a/c in standard cargo bins with tooling etc
in all have received,unhung,rehung new and dead eng back on aog a/c the 5 pod and dispatched in less than 15 hrs (jt9)believe that a cf6 would be quicker due not having to r/r the cascade vanes which you have to swop on jt9
don't see it very often but fun was had whilst doing them
Joined: Jan 2003
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From: Manchester
As an aside to this, my father was on the Vulcans during the 50's. Some bright spark designed a jig to " 5th pod" an Olympus into the bombay of a Vulcan. The idear was that you could get a spare engine anywere in the world in a matter of hours in a Vulcan. The two engine stands, the mini hoists, all the tools and the team of men to do it would then be loaded into a Beverly and then trundle off at about 150kts and take three days to catch up!. Needless to say the idear was not used very often!.
Rgds Dr.I.
Rgds Dr.I.
Joined: Aug 2004
Posts: 31
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From: yorkshire
Mounting points
Please excuse my ignorance but being from rotary wing I have no knowledge of this system, but find it very intresting. Do any other aircraft come with the hardpoints on the wings? Are the hard points on both sides? Could any other form of cargo be carried there, ie a cargo pod? Is there any form of life penalty on the airframe for using external load hardpoints?
