DC-8 two-engine ferry?

[CargoOne]

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?

[No comment]

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?

[BlueEagle]

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.

[barit1]

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"!!!!

;)

[CargoOne]

BlueEagle

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

[HotDog]

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.

[WHBM]

Not sure about the FAA position though!
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).

[Seloco]

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.....

[Few Cloudy]

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.

[ferrydude]

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

[Sheep Guts]

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

[Nubboy]

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

[oldebloke]

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:

[blue up]

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!!!!!!!!!!!!

[16 blades]

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

[barit1]

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

[Old Smokey]

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

[16 blades]

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

16B

[XL5]

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.

[barit1]

A DC-8 will stay airborne with just one engine running - at least in the sim.

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

[Yak97]

Many, many moons ago at CVT I watched a C337 (Acorn Computers?) which couldn't start the rear engine (think his starter had failed).

The pilot elected to do a high speed run down the runway and try and windmill the engine into starting.

1st & second runs, no joy. By now he was getting desparate as I think Cambridge, his destination, was due to close. So the third run, he didn't stop.

To the amazement of the many sightseers he got airborne, due mainly to the curveture of the earth, and disappeared towards Cambridge. Boy, when he raised the undercarriage that prob took the top of a few trees.

As we never saw an accident report we assume he made it.

[ferrydude]

XL5 probably has described the usual methods for such on the DC-8. As he posted, 3 engine ferrys are dicey. One was lost here in the US a few years back when a specialy trained crew did not follow those special procedures and lost the aircraft due to a failure to understand Vmcg. Knowing some previous stunts performed at Arrow, there is not telling what they are up to these days.

[GlueBall]

It can only be about a 2-engine taxi. There is no record of a 2-engine ferry flight of any DC-8 anywhere, not even by Douglas test pilots. There is no procedure and no training for 2-engine ferry flights. It's not approved. It's illegal. It's dangerous....because there is insufficient thrust to climb an empty airframe on 1 engine after engine failure at rotation speed.

:zzz:

[Ignition Override]

Ferrydude: I just flew a trip with a guy who years ago rode around on the jumpseats with many airlines. The USAF required inspectors to ride on various passenger and cargo planes, in order to be approved to carry Air Force personnel and cargo. He also attended ground schools.

He told me that Arrow Air lost the contract after the disaster in Gander. The Canadian Safety Board was split on the primary cause of that accident, which was filled with soldiers.

He also visited the c0ckp1t of the Spruce Goose in McMinnville, Oregon. Said that the plane had a gigantic hydraulic pump, as big as a small car! When it suddenly flew from the harbor at Long Beach, it actually had no hydraulic pressure for the flight controls! Hughes was apparently determined to lift off, but I don't know if he was aware of the hydraulic failure. He had been told that the plane could never fly and was very tempted to prove the critics wrong. There were panels around his left seat with many controls and gauges. :ooh:

Could the Goose have cruised on just four engines?

Years ago Buffalo Airways lost a 707 while attempting a three-engine takeoff in Kansas City. There seems to have been little or no such required training for the crew, regarding when to advance the asymmetric throttle lever. Many small US companies expect their employees to 'improvise', otherwise many of them never could have stayed in business.

[northwing]

People used to play games on piston-prop airliners, feathering one outboard engine and idling the opposite one when the weight had reduced sufficiently. However, with a jet range is always going to come with height so it would be uneconomic to shut one down.

The Nimrod certainly shuts one engine down to extend loiter and a second would be taken down to idle at light weight or even shut down completely if climb were possible on 1 remaining engine, although this would be a pretty rare situation.

A Hercules will climb with 2 engines feathered at light weight. I've been there.

Most 4-engined types will have a ferry takeoff clearance to allow the aircraft to be recovered to a main operating base for rectification. This is strictly a no-pax operation of course (except for some lunatic in a 747 who diverted into Germany from somewhere in the far East with seat straps holding damaged fan blades still). It needs a certain amount of forethought but is not inherently dangerous. It has been tested on a Tristar although there was some doubt about whether the nosewheel steering had been stalled during the attempt to keep the aircraft straight.

[ferrydude]

Glueball, I'm well aware of that fact that a two engine take-off is not approved, nor likely to occur. I believe I was the first to post that here, but thanks for the reminder. Ignition Overide, are you sure you are referring to the correct accident?
The DC-8 3 engine attempted take off I was referring to was In Kansas City also.
I recall the Buffalo Airways loss of a 707 at Kansas City occured on short final approach, a CFIT accident, not related to engines. It is a shame about the old Arrow, and the loss in Gander. This one is still quite controversial amongst DC-8 crews.

[LEVC]

i was told by a ground instructor that the 757 had a better range flying in one engine, being the cause that is overpowered and it's
engines run at relativly low power setting , and as someone pointed out in a previous post the fuel comsumption is reduced when flying on one engine, while saying that he was showing the calculation tables of the acft.

If the DC8 is also overpowered , i guess it could be done , shut down
two engines on CRS and save 10 or 20% of fuel, in the other hand i don't think it would be allowed by the CAA, FAA.....

Could somebody taht has flown the 757 confirm the info?

[Maurice Chavez]

As an ex Diezel 8 driver, I can tell you that there's no such thing as a 2 engine ferry....2 engine taxi on 2 & 3 yes, as somebody alse here pointed out, the EDP's are on these engines. It's saves almost next to nothing on fuel as you'll have to cross bleed start the other 2 remaining. The pneumatic manifold on the diezel 8 is known to leak a lot, therefore a lot of thrust from the other engines is required. 3 engine ferry's does not require a "special crew". All crews are trained for 3 engine ferry flights in the simulator, at least for all the diezel 8 operators I worked for. Also there's a little thing called 3 engine ferry ops manual, these "special crews" read them before commencing the flight and go through a very extensive briefing. Hope this clears some about the mighty 8...Oh almost forgot, you can actually taxi the 8 on 1 & 4 only, as the aux pump feeds the whole general system, not a good practice, but yes, you could....

Nubboy:

I think I know who you mean, with that 707 taking off on 3 to get the 4th starting.....Good ol' Sport M.........

[ferrydude]

Anything less than the 70 series is underpowered. I doubt seriously if there are any efficiency gains to be made by shutting one or more down in cruise on any -8 version. I do know that this has occured on several occasions, but for entirely different reasons. Some engine component times were reaching their limits and the scheduled trip could not be completed without exceeding them, so the engine was secured for a fair amount of the cruise portion. These days, I'd just refuse the trip, but heck, there was a war on!

[ou Trek dronkie]

Look, believe the oTd, you just do not try a three-engined ferry in a four holer. We did it once out of a desolate African airfield, it was terrifying. Terrifying. (no pax and essential crew only, daylight, good VMC etc, all in the book).

We also did some training on three-engined take-offs afterwards, as a result. Further result : even more terror AND a burst tyre. Much embarrassment too.

You may save fuel if you can safely close down a donk when you are holding, maybe, but just consult the FOM and it will tell you everything. Best not to try non-SOP stuff I reckon, don’t be clever, just be compliant. It’s much safer.

And if you do things which are not in the book, well, what must I say ? You are an idiot.

The operational Take-off dude, well, used to be.

oTd

[moggiee]

When it comes to fuel burn, in terms of air nautical miles per Lb/Kg most aeroplanes are MORE economical with one engine shut down.

This is probably to do with two factors: Running the remaining engines at a more efficient (higher) RPM and cruising at lower speeds, and therefore creating less drag.

Worth checking the perfomance manuals on this one, chaps.

And speaking from personal experience, I can categorically state that the VC10 flies quite well on two engines - even if the two which are shut down are on the same side!

I wouldn't want to get airborne on two, but it gets off the ground on 3 quite nicely.

[Maurice Chavez]

Ou trekker,

Did many 3 engine ferry's on the diezel 8, never had a problem, just operate according to the book. Your F/E is most valuable here....

As for some draadtrekker pointing out here; shutting down an engine to save fuel on a DC-8? Uhhm, yeah right. Let's get from FL350 (it only takes you over an hour to get there, not a 70 series...) back to FL260 on 3 engines.....Douglas has a thing called Long Range Cruise...Ever heard of it??

[moggiee]

Maurice - shame on you using such rude words! Wash your mouth out with soap.

I'd rather be a draadtrekker than a moffie with an unhealthy intest in holani (not suggesting that you are such a person, by the way!).

[ou Trek dronkie]

Maurice,

Well, yes, I only flew LRC except in the silver days before OPEC came along. I remember 7 US cents/USG … I gotta agree with you of course. But sooner you than me mate. (Ou drek skrikker).

What I was suggesting is what happens if you lose a donk on the wrong side, know what I mean ? Like, I mean, you know, on rotation.

EINA !!

And there is precious little you can do after the magic moment between Vmcg and Vmca. My memory of these mystic FLAs (four letter acronyms) is a bit misty, but I seem to remember it’s about reaction time, or have I finally lost it ? (It's late and the Roman roads have been particularly difficult today).

And as for shutting down an engine to save fuel,

“i was told by a ground instructor that the 757 had a better range flying in one engine, being the cause that is overpowered and it's engines run at relativly low power setting , and as someone pointed out in a previous post the fuel comsumption is reduced when flying on one engine, while saying that he was showing the calculation tables of the acft” …

And the guy then says :

“shut down two engines on CRS and save 10 or 20% of fuel”

Well, I mean, what was the point of Mr Boeing or Mr Douglas putting the extra engine on and all that ? Why do I read such twaddle ?

Maurice, Yes, of course, you have words of wisdom. Once you are airborne, it’s OK. It’s always about altitude, as you rightly say. Did a fair bit of panel work meself and always believed in the book.

I say again, fly by the book, unless you know better than the guys who wrote it. Just believe, it’s easier - and safer.

Ou Tired dronkie

[moggiee]

oTd:

There should not be a gap between VMCG and VMCA. V1 must ALWAYS be lower than either of these speeds so that the loss of the critical power unit does not lead to loss of control.

For 3 engined take off the performance is calculated on the understanding that the second engine will fail at V1 and the take-off will be continued.

It is a matter of record, certainly for twins, that in most cases air nautical miles per Lb/Kg INCREASE when on one engine. If I can find the numbers from my copy of the B737 QRH I'll post them.

[ferrydude]

Hey Moggiee, the discussion is whether there is an efficiency to be gained in any area by securing one or more engines on a DC-8, not a twin, or a trimotor, etc.
You got any data that backs up your statement for a DC-8? I say balderdash, it just aint so.

[mustafagander]

moggiee,

As far as I understand it, by regulation, V1 MUST be above Vmcg. Think about it, the fly on case could be very exciting if you were to try to continue the T/O from a V1 below Vmcg!! :uhoh:

Vmca must be at or below Vr, or, to put things in the right order, Vr must be at or above Vmca. Once again, give it a bit of thought.

[alatriste]

As far as I Know, range will be increase when flying on one engine only if we HAVE TO fly at very low altitude e.g. PRESSURIZATION FAILURE.
In a twin MD 80 flying at FL 130 at LRC and GW 54T Specific Range is 117 nm/t of fuel on 2-eng, while with one engine shut-down Sr increase to 121 nm/t, not much, but a little increase.
At higher FL, 2 engine specific range is higher.
At low altitudes, when 2 engines are runnig for LRC, power settings are really very low, therefore engines are very inefficient, if you shut down one engine, remaining one will increase N1 and will be more efficient.
I don´t know about DC-8, but I guess that at low GW and FLs up to 250 the same may apply when flying on two engines instead of 4.

REGARDS

[ou Trek dronkie]

Moggiee,

You say :

“There should not be a gap between VMCG and VMCA. V1 must ALWAYS be lower than either of these speeds so that the loss of the critical power unit does not lead to loss of control.”

Well, when I used to fly, Vmcg was a ground speed and Vmca was a flight speed, so I am not quite sure what your understanding of V1 is ?

Also :

“For 3 engined take off the performance is calculated on the understanding that the second engine will fail at V1 and the take-off will be continued”

I always thought V1 was a recognition speed ? And I must say my understanding was quite different to yours, but it always worked fine.

Try these definitions :

Vmca MINIMUM CONTROL SPEED (AIRBORNE)

Vmca is the minimum flight speed at which the aircraft is directionally controllable. The conditions for Vmca include the critical engine becoming inoperative and windmilling, using a maximum of 5° of bank towards the operating engine, which is at maximum thrust, landing gear up, flaps set at take-off setting and the most rearward CG.

Vmcg MINIMUM CONTROL SPEED (GROUND)

Vmcg is the minimum control speed on the ground at which the take-off can be continued using aerodynamic controls alone, when the critical engine suddenly becomes inoperative and the remaining engine(s) are at take-off thrust.

These might have altered slightly ? Long time since I saw four thrust levers on one console.

V1 – can’t remember it exactly, but in practice it is a historical speed as you make your mind up to go long before it arrives

Ferry Dude, Thanks for bringing the topic back on line.

oTd

[Maurice Chavez]

ferrydude:

You are right! As I pointed out earlier, there is no fuel saving on the DC-8, both 50 and 60 series (don't know about the 70 series, haven't flown them much) with shutting down an engine in cruise. Even at low weights you will not save any fuel doing this, and believe me, I have done quite a few 3 engine ferries on them.

Proper 3 engine ferry technique for DC-8 is as follows (outboard engine inop): Calculate MTOW for the particular runway. Use V speeds for the MTOW (high speeds). Spool inboards to 1.4 Epr, brakes on. Set T/O thrust on inboards, when T/O EPR is reached, release brakes. At 80 KIAS bring in slowly the outboard engine (best done by the F/E). With the gradual power from the outboard coming in, compensate with rudder. Outboard engine has to be at T/O EPR before 110 KIAS.

Since using V-speeds for MTOW, it doesn't matter if you would loose another donk at V1, since you're actually allready at Vr for your actual weight....

Hope this clears things up a bit.

Ou dronkie, kom man ons drink nou 'n dop!!!!

[moggiee]

oops - finger trouble! I meant to say that V1 must be HIGHER than Vmcg.

My understanding of V1 is, for the record:

V1 is a decision speed at at which you have the option to stop or go in the event of a failure of the critical power unit.

It is slow enough for you to be able to stop in the remainder of the ASDA but high enough for you to be able to continue in the remainder of the TORA and TODA. It is also ABOVE Vmcg in order that you are able to maintain directional control up to Vr.

There is a two second "reaction" time built in to the calculations so that if you spot a failure at V1 there is sufficient time for your brain to process the information and your hands and feet to take the appropriate action to reject the takeoff.

However, this is not the same as allowing an extra two seconds of decision making time - the two seconds is for reaction to a decision made at V1.

Ferrydude: I was not commenting upon the DC8 per se (read my posts and you'll see that is the case). I was responding to a comment by another contributor who claimed that no aeroplane would have a better range with an engine shut down.

This is not the case, for example with the C130 as mentioned by another contributor, and with the B737, Jetstream and others. Now, I know that the B737 and Jetstream are twins, but I'm sure that the last time I looked a Herc had 4 motors!

[ferrydude]

Fair enough Moggiee, I'll re phrase my post. I say there is no way in hell that the Diesel 8 is more efficient in long range cruise with one or more engines secured. Anyone out there pontificating about such efficiencies, please prove me wrong. Meanwhile, I suppose I'll go an dig through the cellar for the old manuals.

[oldebloke]

Moggiee,nearly right V1 as defined with FAA part25-107 stipulates that the failure(VEF) has to be 'recognized' and 'reacted to'BY V!.....
the 2 seconds part is in the 25-109?"TAke off Distance"...In that a 2 seconds worth of distance ,at V1 speed,is included in the T/Off distance...FAA/JAR 25-109(a)(2)
JAR reads the sameway(JAR 25-107(a)(1) :ok:

[ou Trek dronkie]

Maurizio,

Yes, that is how I remember it too. The only other point that emerges from the past is that the max BRW was severely reduced, quite a surprising amount. But it's all such a long time ago.....

And tonight it's a reunion with an ex-air force colleague, so I shall definitely take up your your brilliant suggestion. Maar dit sal 'n dop of twee of meer seker wees.

ou Drek Toppie

[jojodel]

On DC-10 and MD-11 there are official procedures for 2-eng. ferry
flights in case of technical problems to reposition the aircraft.
No passengers allowed and many procedures/restrictions to be
followed. The company I worked with was rather generous applying 2-eng. ferry on the MD-11 until they had a fire warning
on one of the life engines on such an occasion. It was a false warning but after that event things were handeled more re-
strictive.
I don't think you'll be able to save fuel on a passenger jet by
shutting down engine(s) in cruise-you'll be slower and will have
to fly lower-just check respective tables for all eng. cruise against
eng. inop. cruise. Not to mention possible legal requirements.
And some engines don't like beeing windmilled for
hours (lubrication problems).


Cheers, jojodel

[flap15]

While in the states on a Metro III course I heared about drug runners using Metro's to ship from South America into the states and extending there range by shuting down one and cruising on the other. This results in a 50% reduction in fuel flow and about a 25% loss of speed. When you do not have to conform to regulations there are some great savings out there.

[farqueue]

Trying to get a Mixmaster off on one is an excercise in patience! Like about 11,000' of it with just the rear, more if it is front only! I'll pass on that unless it is at Edwards thanks.

That said, shutting down the front and flying on rear only increased both range and endurance significantly. Was done as a SOP by the spotters for Chennes Beach Whalers long ago.

Anyone who cycles the gear with only one turning is in for a Green, Round, type of time!!

[hawk37]

"While in the states on a Metro III course I heared about drug runners using Metro's to ship from South America into the states and extending there range by shuting down one and cruising on the other. This results in a 50% reduction in fuel flow and about a 25% loss of speed. "

Wow. If you can get that much more range by shutting down just one engine, imagine the possibilities with a DC8 shutting down 3!!

Hawk

[Paul Wilson]

From reading about the antics of drug smugglers, they seem to like flying at low level, which would mean that 2 engines would be operating at low power (inefficient), so shutting down one and perating the remaining at high power (more effiecient) would seem doable for increased range. Also the smugglers have , I would imagine, a somewhat cavalier regard for rules, getting caught for flying on one, would pale into insignificance compared to a ton of coke in the back.

[chofuan]

I am a DC8 check airman and during my training at UAL the 2 eng ferry flight was never mention. In the AFM doesn't even consider the 2 eng Ferry flight, all the performance charts are made for the 3 eng ferry flight. Besides all that, I don't think that the DC8 at any given weight with any kind of engines could fly in the event of a 3rd eng failure.

At a weight of 300.000lbs the airplane needs way too much power to start the taxing on 2 engines.