DC-8 two-engine ferry?
 

While reading "Airline Cargo Management" March 2005 issue I have noticed the article on how airlines are reducing the fuel burn. Here is the small extraction:

[Arrow Air / Miami]
...Arrow has lowered its fuel consumption fleetwide by 12% over the past year, says Visconti. This has been achieved by measures such as two-engine ferry flights with its four-engined DC-8, expedited taxiing times at airports, restricted use of APU on its DC-10s, blah-blah-blah..

2-engine ferry flights on DC-8? :confused:
What does it exactly mean?

I guess its possible,
Completely O/T and its not my domain at all but dont the RAF Nimrods have the capability to patrol around on 2 instead of 4 to save fuel?

I think what it means is that on empty legs they will get airborne on four and when at the selcted cruise level they will shut down two engines, relighting them during the descent and land with four running.

Ferry? or taxi?
 

I think we have some journalistic license encroaching here - almost certainly meaning "2-engine taxi". I cannot understand how ANY kind of ferry flight saves Jet A anyway.

My favorite example of media brilliance was a photo caption - a helicopter on a dolly being hand-pushed across the ramp. The writer tells us that the chopper was being "push-started"!!!!

;)

BlueEagle

I thought the same, but is it actually legal procedures and safety wise? Never heard before about such practices in commercial aviation...

No way Jose! Total fuel burn at the lower two engine flight levels , even at low zero fuel weights will surely exceed four engine cruise fuel flows at four engine levels. Just look at the performance charts.

Probably fine with it as the US Navy/Coastguard does the same with their Lockheed Aurora 4-engined turboprop maritime patrol aircraft as well (in fact that may be where the RAF got the idea for the Nimrod procedure from).

I believe that RAF Javelins would shut down one engine to conserve fuel when on high altitude loiter over the North Sea during the Cold War. When Ivan the Bear hove into radar view the engine would be relit for intercept and escort away from the coast.

Not sure if this works for more modern types though.....

If you are flying cruise FL, you are for sure better off on 4 than 3 or less engines.

If you are flying at low level - for instance in the Nimrod anti sub role - you will save by shutting 1 (2 depending on weight) down.

There is not an approved procedure by Douglass or Boeing for a two engine take-off on the Diesel 8.

Maybe he got his types mixed up there. Can you do a 2 engine ferry with a DC-10? Maybe thats what he was saying.

Sheep

Surprised no one's (yet) mentioned the urban legend of getting a 707 airborne on three to air start the fourth!;)

Although nonstandarn three engine ferries were performed on the DC8/B707-747/and the coronado(ask Spantax)..Nonstandard in that the COA validity was suspect.I did 5 in 10 years on the 8,just to move the aircraft for engine changes....Several restrictions applied,reduced flap(higher speeds for 2 eng'VMC)reduced weight,240000,instead of the gross 352000..Takeoff thrust on the assymetric engine had to set by VR,and Captains were required to 'demonstrate' the proc' n the regulars Sim's.Eventually the procedure was 'phased' out,with the distribution of engines through the network..
Some 'charter' carriers were known to'idle' #3 in cruise to avoid unnescessary fuel stops... :ok:

Didn't Alderney Air Charter do single engine ferries? I think I recall the boss (Pete Moss?) saying that if the Cesna 337 lost a donkey on the island that he would unbolt the prop, bolt the spinner back on, strap the prop to the pax seat and ferry the bird back to the mainland.
Ahhhhhhh! the good ol' days!!!!!!!!!!!!

Grimrods often throttle back an inboard whilst doing a LL patrol or SAR sortie over the sea- this does save fuel, but I believe it's more to do with having instant(ish) throttle response in the event of having to climb away fast, since they are so over-powered they would have to be throttled back a long way on all 4, with the associated spool-up time.

3-engine take-offs are perfectly possible. We do them as a matter of course in Albert (simulated in the aircraft, or real in the sim) - it is a basic training requirement. Plenty have been done for real as well.

16B

unbolt the prop
 

Almost 50 years ago, when the Aero Commander was just entering the market, the factory unbolted one prop and stowed it in the cabin, then ferried the bird on one from OKC to TEB to the business aircraft convention.

Made great press!:p

2 emgines shut down at quite low levels and appropriate weights to sustain a further engine failure, a la Nomrod, wonderful for ENDURANCE and loiter capabilities, but an absolute DISASTER for range capability.

Even if it were safe AND legal for civil operations, there would be absolutely nothing to gain in improved range capability, i.e. a lesser fuel burn for a specific ferry difference. One engine shut down out of 4 may make a difference.

Old Smokey

It does. Holding at medium level with 1 shut down in Albert saves about 5% on burn, at best speed.

16B

To taxi with inboard engines running ( they're the ones with the hydraulic pumps) with a delayed start for the outboards is standard practice. Typically saves in the order of 1000lbs of fuel and is smiled upon by the bean counters.

A Three engine take-off and ferry for maintenance under a special operating certificate with a crew especially trained for the stunt ( things can/do get squirrelly as asymmetrical power is applied on the take-off roll) is also standard practice.

Shutting two down enroute increases endurance but knocks the specific fuel flow down south, absolutely no commercial advantage to it. The bean counters would soon start screaming.

A DC-8 will stay airborne with just one engine running - at least in the sim. If shutting down two were to make money think of the savings to be had with three blowing in the wind.

What model are you talking about? 50/60/70 series?