5 Engines on a 747

CaptainSkidmark

We've all seen the pic of the EI 747 carrying the 5th engine,

Well here it is from the inside on a Qantas 747 yesterday!

Mister Jingles

Why the five engines though ?

Celtic Mech

The 747 has the capability to transport an Engine....id imagine its transporting one as another 747 in the fleet requires an engine to be replaced. Its a great capability of the 747 to be able to transport a spare!

xflyer

It's only used during take off on short runways, it's shut down for the cruise but can be restarted anytime should the need arise. It was originally requested by Japan Airlines because they wanted to service some of the smaller airports around Japan and use them for short haul, high density routes. With the fifth engine you squeeze in 550 people and take off from airports with runways as short as 2000 metres. They originally wanted six engines but it was found that the weight and drag of the sixth engine actually forced a reduction in the number of pax.

Other airlines have of course taken advantage of fifth engine, notably Qantas. Aer Lingus did experiment with it as mentioned. They were hoping to use it on the London route with 500 passengers flying into Southend. But it never worked out.......................................................


On the other hand all of the above is about as accurate as most of Wikipedia. In fact the Boeing 747 has a mounting which is used for the transport of spare engines, not particularly for the aircraft itself but used in the transportation of recently refurbished engine or indeed transporting engine to a maintenance organisation. If you look at the picture you can see the LP Compressor has had blanks added and covers on the intake like.
It's not commonly used anymore.

Now that is the truth.

Spoilsport Celtic Mech, quick move your post after mine.

Run_to_da_hills

CaptainSkidmark

They were only transporting the engine, as were aer lingus.... they didnt use it as an engine.

the 747 can fit another engine to transport it it cannot run the engine, i dont know where you got that information from??

St. Leibowitz

I think the original thinking for this was due to the large size of the JT9 or RB211 fans compared to the aircraft in service at the time. Most freighters were 727s, 707s or DC-8s. With the 707 having a cabin height of 2.38m, and the JT9D-7 having a fan diameter of 2.34m It would have been difficult to transport spare or replacment engines if a widebody aircraft went tech away from a maintenance base and needed a replacement engine. A podded engine on a dry mount with the fan blanked to reduce drag could be fitted to fly in a spare, or to take a defective engine back for maintenance.

The Air India flight 182 which was lost off the Cork coast in in 1985 due to a bomb was carrying a podded 5th engine back to India from Canada. It was delayed for almost 2 hours to have this engine fitted. Often wondered if this hadn't happened, would the bomb have gone off on the ground in Heathrow, rather than in the air.

AfterDusk

CaptainSkidmark wrote: »

They were only transporting the engine, as were aer lingus.... they didnt use it as an engine.

the 747 can fit another engine to transport it it cannot run the engine, i dont know where you got that information from??

I think you need to read that post again

xflyer

i dont know where you got that information from??

It's on wikipedia, it must be true.:D

Delancey

The Air India 747 brought down by Sikh extremists off the Cork coast in 1985 was carrying a 5th engine at the time which was faulty and being returned to India from Toronto for repairs when the plane exploded.

ScabbyLeg

Maybe Qantas have learned from their A380 teething problems that it's better to have one engine too many... :pac:

cyrusdvirus

St. Leibowitz wrote: »

I think the original thinking for this was due to the large size of the JT9 or RB211 fans compared to the aircraft in service at the time. Most freighters were 727s, 707s or DC-8s. With the 707 having a cabin height of 2.38m, and the JT9D-7 having a fan diameter of 2.34m It would have been difficult to transport spare or replacment engines if a widebody aircraft went tech away from a maintenance base and needed a replacement engine. A podded engine on a dry mount with the fan blanked to reduce drag could be fitted to fly in a spare, or to take a defective engine back for maintenance.

The Air India flight 182 which was lost off the Cork coast in in 1985 due to a bomb was carrying a podded 5th engine back to India from Canada. It was delayed for almost 2 hours to have this engine fitted. Often wondered if this hadn't happened, would the bomb have gone off on the ground in Heathrow, rather than in the air.

That was actually the aim. There was another bombing in Japan that day, at Narita, on another Air India plane