B747-100 engine problems on early versions
Makes you wonder if the early JT9D was the start of the long road downhill for Pratt & Whitney.
By 1970 Pratts had a virtual monopoly of the civilian jet market. Boeing and Douglas used them exclusively on their model range, small to large. GE were not into civilian aircraft (despite having done the engine for the Lockheed Galaxy, which seems to have been a lot more reliable than the early JT9Ds), and Rolls were reduced to a few niche British-built aircraft.
But after the JT9D Pratts were never held in the same high regard again. The Tristar went for Rolls, and while the DC-10 offered GE and P&W equally, only two airlines ever went for the Pratt engine. The A300 started with GE, P&W coming along later in second place. Likewise the 757 (choice between Rolls and Pratt) and the 767 (GE or Pratt), P&W were regarded as second choice. And so onward through subsequent types.
Nowadays they seem to be slowly but steadily dropping market share percentage every year. Somehow the far-ahead leader lost it.
By 1970 Pratts had a virtual monopoly of the civilian jet market. Boeing and Douglas used them exclusively on their model range, small to large. GE were not into civilian aircraft (despite having done the engine for the Lockheed Galaxy, which seems to have been a lot more reliable than the early JT9Ds), and Rolls were reduced to a few niche British-built aircraft.
But after the JT9D Pratts were never held in the same high regard again. The Tristar went for Rolls, and while the DC-10 offered GE and P&W equally, only two airlines ever went for the Pratt engine. The A300 started with GE, P&W coming along later in second place. Likewise the 757 (choice between Rolls and Pratt) and the 767 (GE or Pratt), P&W were regarded as second choice. And so onward through subsequent types.
Nowadays they seem to be slowly but steadily dropping market share percentage every year. Somehow the far-ahead leader lost it.
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In 1978 I was told that if P&W did not sell another new engine for ten years, their business would still be bigger than GE strictly on spares sales. 
'twas prophetic.
'twas prophetic.
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Diddy,
I should have RTFQ..... you asked about stalling on the ground. I know that of the three engines we operated in the 80's: The -7A's, 7F's, -70A's and the Q's the 70A's were the worst. They frequently over-tempted on start (tail winds up the pipe made the engineers arms sore waiting for max motor,) They had "transient" overtempts a lot and on T/O, Climb, but especially on reverse. Frequently as well, they just wouldn't mechanically come out of reverse (not sure if it was the reverser sleeve sticking or what.) The reverse lever would go haywire and kind of get stuck in transit (neither rev or stowed command position) and then you only had a second or two to save five million dollars. The mechanical drums on the EGT would take off like a loto slot machine clicking to beat hell, and it was a race to kill it before it blew the redline. At our outfit, the engineer had permission to kill an inboard any time without asking on the ground, and an outboard if the captain concurred. Even on rollout! The Q's were the best of the JT9D's.
It was the end of the Golden Age of Jumbo flying. And I can't think of anyplace I'd rather be than at a bar in hong kong or NRT or someplace with those fine gentlemen.
Cheers!
I should have RTFQ..... you asked about stalling on the ground. I know that of the three engines we operated in the 80's: The -7A's, 7F's, -70A's and the Q's the 70A's were the worst. They frequently over-tempted on start (tail winds up the pipe made the engineers arms sore waiting for max motor,) They had "transient" overtempts a lot and on T/O, Climb, but especially on reverse. Frequently as well, they just wouldn't mechanically come out of reverse (not sure if it was the reverser sleeve sticking or what.) The reverse lever would go haywire and kind of get stuck in transit (neither rev or stowed command position) and then you only had a second or two to save five million dollars. The mechanical drums on the EGT would take off like a loto slot machine clicking to beat hell, and it was a race to kill it before it blew the redline. At our outfit, the engineer had permission to kill an inboard any time without asking on the ground, and an outboard if the captain concurred. Even on rollout! The Q's were the best of the JT9D's.
It was the end of the Golden Age of Jumbo flying. And I can't think of anyplace I'd rather be than at a bar in hong kong or NRT or someplace with those fine gentlemen.
Cheers!
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'Bleed system problems. On our -100 course we were taught four different bleed system configurations - and they were the ones that worked (more or less)! The compressor had either had more air than it could handle or not enough; so it was prone to compressor stall: Getting the balance right seemed to have been a matter of trial and error by P&W in the early days of the JT9.'
Ahhh. the old JT9......
When I did my ground engineers course when the instructor came to describing the bleed system he said that when P&W were first designing the bleed system they threw a hand grenade in the front and where the shrapnel came out through the casing, that is where they put a beed valve.
I had a tailpipe fire on one engine run I did early one morning. Fuel on at max motoring (22%) and there was instantaneous light up. I shut the fuel off, kept motoring and watched the EGT literally go off the clock. Just as the fire brigade turned up the EGT started to go down. Afterwards the headset man said he did see a mist coming out of the back of the engine when I started motoring but he had assumed it was the rain he was standing in.
It turned out that what had happened was that the condition actuator (HP Cock) had stuck open after being functioned in the hangar (with the guy in the cockpit just watching the LP Valve postion light as a check for correct operation). So when I started motoring the fuel pump pumped all the fuel that was in the supply pipe from the wing spar valve into the combustion chamber just waiting for the ignitors to burst in to life. Then when the start lever was placed to run the ignitors came on and the spar valve opened, replenishing the the fuel supply in the pylon pipe. So the EGT would only decrease when that fuel was exhausted.
On stripdown the faulty Condition Actuator was found contaminated with engine oil. The JT9 oil leaks being another story.
Ahhh. the old JT9......
When I did my ground engineers course when the instructor came to describing the bleed system he said that when P&W were first designing the bleed system they threw a hand grenade in the front and where the shrapnel came out through the casing, that is where they put a beed valve.
I had a tailpipe fire on one engine run I did early one morning. Fuel on at max motoring (22%) and there was instantaneous light up. I shut the fuel off, kept motoring and watched the EGT literally go off the clock. Just as the fire brigade turned up the EGT started to go down. Afterwards the headset man said he did see a mist coming out of the back of the engine when I started motoring but he had assumed it was the rain he was standing in.
It turned out that what had happened was that the condition actuator (HP Cock) had stuck open after being functioned in the hangar (with the guy in the cockpit just watching the LP Valve postion light as a check for correct operation). So when I started motoring the fuel pump pumped all the fuel that was in the supply pipe from the wing spar valve into the combustion chamber just waiting for the ignitors to burst in to life. Then when the start lever was placed to run the ignitors came on and the spar valve opened, replenishing the the fuel supply in the pylon pipe. So the EGT would only decrease when that fuel was exhausted.
On stripdown the faulty Condition Actuator was found contaminated with engine oil. The JT9 oil leaks being another story.
Perhaps of minor interest ..... one of the old 747-146's I used to fly had the JT9D-7A's on it and it still had most of the hot section reversers fitted, though locked out.
N4790P
B.A. B747 Engine Fire
Seeking information about a British Airways B747 engine fire and evacuation in Johannesburg in May 1983.
Seeking information about a British Airways B747 engine fire and evacuation in Johannesburg in May 1983.
Those early BOAC 747 flights to JFK often failed to achieve their assigned levels by the Shanwick boundary.
I recall Shanwick requiring one of them to read out each hundred feet of altitude as it painfully clawed its way upward.
Whereas, in contrast the 'superceded' SUPER VC10.......!
I recall Shanwick requiring one of them to read out each hundred feet of altitude as it painfully clawed its way upward.
Whereas, in contrast the 'superceded' SUPER VC10.......!
the lunatic fringe
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I joined the BA747-100/200 fleet in 1987. The aged Captains, and FE's would delight in telling the -3 stories.
One I remember is that at top of descent the FE would be tasked with closing the thrust levers. This was done at a practised and special rate. Too fast or slow, and all four engines would flame out.
Another temporary solution to this problem was the metal bar. It was inserted across the thrust lever quadrant so that the levers could not be fully closed. When it went on and off I am unable to recall.
The -7s that were on the wing when I flew them seemed to burn more oil than fuel.. I remember range was limited by oil consumption!
In round numbers the P&W used 12 tons an hour. The Roller 11 tons an hour.
One I remember is that at top of descent the FE would be tasked with closing the thrust levers. This was done at a practised and special rate. Too fast or slow, and all four engines would flame out.
Another temporary solution to this problem was the metal bar. It was inserted across the thrust lever quadrant so that the levers could not be fully closed. When it went on and off I am unable to recall.
The -7s that were on the wing when I flew them seemed to burn more oil than fuel.. I remember range was limited by oil consumption!
In round numbers the P&W used 12 tons an hour. The Roller 11 tons an hour.
Usual disclaimers apply!
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L377
That 'metal bar' wasn't temporary! IIRC it was fitted on the early 3a powered aircraft to stop you pulling the T/L's all the way back to the gate in flight, otherwise they would flame out
By the time you got on them the compressor and fuel control system (JFC) design had improved somewhat plus the redesigned fuel condition actuator allowed grd. idle in flt and flt. idle when the flaps were deployed.
One thing the JT9d did not like was 'milking' the T/L's. A nice quick steady snap to idle at top of descent allowed the fuel pressure to decay and open the bleeds to prevent a TOD surge. (This usually happened when the EVC had drifted 'off schedule' and a tired compressor.)
18 wheeler
Most of the hot sleeves on our JT9d's were like that. But I do I remember, when they when 'active' many a time with a railway sleeper sized lump of wood trying to knock them forwards to get the light out and lock them out for dispatch!
Another temporary solution to this problem was the metal bar. It was inserted across the thrust lever quadrant so that the levers could not be fully closed. When it went on and off I am unable to recall.
By the time you got on them the compressor and fuel control system (JFC) design had improved somewhat plus the redesigned fuel condition actuator allowed grd. idle in flt and flt. idle when the flaps were deployed.
One thing the JT9d did not like was 'milking' the T/L's. A nice quick steady snap to idle at top of descent allowed the fuel pressure to decay and open the bleeds to prevent a TOD surge. (This usually happened when the EVC had drifted 'off schedule' and a tired compressor.)
18 wheeler
Most of the hot sleeves on our JT9d's were like that. But I do I remember, when they when 'active' many a time with a railway sleeper sized lump of wood trying to knock them forwards to get the light out and lock them out for dispatch!
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As a former ground engineer in the late 1970's I paid off my first house loan inside 18 months with the overtime I made doing engine changes & building up 5th Pod engines to fly in & out around the asian area due to JT9D engine failures!!!!!!!!! I reckon they were the best invention since the Super Connie superchargers !!!!! (which would also allow an engineer to pay off a house loan in 18 months due to failures & incurred overtime..,.... ) Technology , you can't beat it!!!!!!! :
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Worked in Manila with 3 JT9 engined 747-200 - 2 with 7Q,1 with 70A from 1988 to 1992 - 48 months, 53 engine changes!! We averaged 1600 hrs per engine and basically we changed all the engines every 3 months - The last wet lease GPA ever did,I think they must have lost a great deal of money on that contract.
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Bodie Bar
The metal bar that was placed behind the thrust levers was known as the 'Bodie Bar'. From memory there was a USAF pilot who used to do slam accelerations, and decelerations of engines. That is how it got its name. The connection between him and the JT9D-3 I do not know.
Usual disclaimers apply!
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The metal bar that was placed behind the thrust levers was known as the 'Bodie Bar'.........
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Burnt fingers ...
The GE CF6 and Pratt's JT9 both stemmed from the USAF's "Giant Freighter" contest, won by Lockeed with what became the Galaxy. GE won the engine contest, so both Boeing and P&W, as the losers, had problems. Boeing's answer was to propose a low-wing variant of their Freighter proposition, keeping the "upper deck" flight deck location (saving on design time & cost), for which Pan Am's Juan Trippe fell - hard ! And every self-respecting airline followed suit ...
(The high flight deck from the military proposal and its upward-hingeing nose gave an easy-loading, full-length cargo hold, whence the 747F, of course.)
P&W were forced to develop and deliver their engine to suit the Pan Am/Boeing schedule, at their own expense, while GE could benefit from the C-5 development programme (government finance, of course). Unable to keep to the schedule while Boeing turned out 747s which therefore had to have concrete blocks hung on the pylons while Pratt did their best to catch up, the JT9 clearly suffered from the rush, as well as having to be financed from company (United Technologies) funds.
Meanwhile, Boeing too was bleeding money, resulting in the famous 50% workforce cut, and even so nearly went under. Badly stung by the too-rushed JT-9 effort, Pratt was clearly well behind the financial drag curve as well and has, at least on the civil side, moved very cautiously ever since; one lesson being that the military paid better, at lower risk.
(The high flight deck from the military proposal and its upward-hingeing nose gave an easy-loading, full-length cargo hold, whence the 747F, of course.)
P&W were forced to develop and deliver their engine to suit the Pan Am/Boeing schedule, at their own expense, while GE could benefit from the C-5 development programme (government finance, of course). Unable to keep to the schedule while Boeing turned out 747s which therefore had to have concrete blocks hung on the pylons while Pratt did their best to catch up, the JT9 clearly suffered from the rush, as well as having to be financed from company (United Technologies) funds.
Meanwhile, Boeing too was bleeding money, resulting in the famous 50% workforce cut, and even so nearly went under. Badly stung by the too-rushed JT-9 effort, Pratt was clearly well behind the financial drag curve as well and has, at least on the civil side, moved very cautiously ever since; one lesson being that the military paid better, at lower risk.
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The metal bar that was placed behind the thrust levers was known as the 'Bodie Bar'. From memory there was a USAF pilot who used to do slam accelerations, and decelerations of engines. That is how it got its name...
There is also a "reverse Bodie"; starting at idle, begin an acceleration, then chop back to idle. It is a good test of combustor stability.
These tests are part of the engine development routine, and may also be applied as required to field engines.
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The -7s that were on the wing when I flew them seemed to burn more oil than fuel.. I remember range was limited by oil consumption!
In round numbers the P&W used 12 tons an hour. The Roller 11 tons an hour.
In round numbers the P&W used 12 tons an hour. The Roller 11 tons an hour.
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Unable to keep to the schedule while Boeing turned out 747s which therefore had to have concrete blocks hung on the pylons while Pratt did their best to catch up, the JT9 clearly suffered from the rush, as well as having to be financed from company (United Technologies) funds.
Meanwhile, Boeing too was bleeding money, resulting in the famous 50% workforce cut, and even so nearly went under.
Last edited by barit1; 24th Jul 2009 at 02:50.
The 747 early production was in trouble around 1969 (I remember actually seeing the first BOAC 747s at Everett with those concrete blocks attached); it was a couple of years earlier that Douglas got into their substantial production mess, due to a range of issues, among others that Sales took a large number of orders without liaising too closely wth R&D and Production for whether they could all be delivered to schedule, trying to develop the DC9 and the Super DC8 together. Ever the problem at Douglas. Remember, the best US airliner would have been designed by Lockheed, assembled by Boeing, and Sales Marketing be done by Douglas.
Back on the topic of the large fan engines, there was a similar thread here not too long ago about all the issues with the early RB.211s on the first Tristars. One really wonders how RR and P&W ever got their products certificated.
Back on the topic of the large fan engines, there was a similar thread here not too long ago about all the issues with the early RB.211s on the first Tristars. One really wonders how RR and P&W ever got their products certificated.
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Hi,
I'm writing from a UK TV production company, Elephant House Studios. We are making a celebratory two part 747 documentary to mark 50 years since roll out.
Episode 1 covers the epic challenges Boeing faced in the late 60’s as they ‘bet the firm’, racing to create the largest passenger aircraft ever built.
Episode 2 explores the temperamental early engines, the long term success of the aircraft, it's impact on the aviation business, signing off with a nod to the end of an era.
The archive led documentary series will air in 2018 - in time for the 50th anniversary of the aircraft. I would be interested to hear from people involved in the early years 65'-75' or those who spent their careers in or around the aircraft.
For budget reasons we are limited to where we can film these interviews. Seattle or UK, in May 2018.
Perhaps you were hands on, earning amazing overtime dealing with the early PW engines, were on the assembly line at Everett, flew one for thirty years, or know the right outspoken cabin crew who can tell a good tale?
As this is a a UK documentary series, airing in the UK first, we would love to find British angles on a US story - perhaps you are a Brit who worked at British Airways or Roll Royce?
If you think you might be of interest and can talk confidently regarding the aircraft and your part in its story, please do get in touch [email protected]
Please remember that I can only accommodate people based in the Seattle area or the UK, filming in May 2018, apologies for this limitation.
Kind regards,
Nick Watson
I'm writing from a UK TV production company, Elephant House Studios. We are making a celebratory two part 747 documentary to mark 50 years since roll out.
Episode 1 covers the epic challenges Boeing faced in the late 60’s as they ‘bet the firm’, racing to create the largest passenger aircraft ever built.
Episode 2 explores the temperamental early engines, the long term success of the aircraft, it's impact on the aviation business, signing off with a nod to the end of an era.
The archive led documentary series will air in 2018 - in time for the 50th anniversary of the aircraft. I would be interested to hear from people involved in the early years 65'-75' or those who spent their careers in or around the aircraft.
For budget reasons we are limited to where we can film these interviews. Seattle or UK, in May 2018.
Perhaps you were hands on, earning amazing overtime dealing with the early PW engines, were on the assembly line at Everett, flew one for thirty years, or know the right outspoken cabin crew who can tell a good tale?
As this is a a UK documentary series, airing in the UK first, we would love to find British angles on a US story - perhaps you are a Brit who worked at British Airways or Roll Royce?
If you think you might be of interest and can talk confidently regarding the aircraft and your part in its story, please do get in touch [email protected]
Please remember that I can only accommodate people based in the Seattle area or the UK, filming in May 2018, apologies for this limitation.
Kind regards,
Nick Watson
Eastern leased three B-747-100 from Pan Am and operated them JFK-MIA and JFK-SJU. They optimistically expected to get over 13 hours a day utilization on these relatively short haul flights. We depleted Pan Am's stock of spare engines in no time. No one mentioned the common failure of the inner case. You would find a piece of the inner case in the overboard bleed screen. Those early engines were not good and the engine change crews became very proficient. To put it politely, the engines were immature and needed another year or two of development.
In a fit of insanity, the Marketing people put one of the beasts on the Air Shuttle for the Thanksgiving rush. It flew EWR - BOS. Remember that the tickets were sold in-flight, The flight was so brief there was no time to complete the sales so the aircraft would sit for almost an hour after landing to allow the complete the sales. The engines did not like flight legs of less than an hour and the inevitable happened. It had to be ferried to JFK for the engine change. The operation was not repeated for the Christmas rush.
Years later, when I was at Orion Air, we operated B747-100 for UPS. We had a celebration when the last -3 model engine was replaced by the so much better -7A models.
In a fit of insanity, the Marketing people put one of the beasts on the Air Shuttle for the Thanksgiving rush. It flew EWR - BOS. Remember that the tickets were sold in-flight, The flight was so brief there was no time to complete the sales so the aircraft would sit for almost an hour after landing to allow the complete the sales. The engines did not like flight legs of less than an hour and the inevitable happened. It had to be ferried to JFK for the engine change. The operation was not repeated for the Christmas rush.
Years later, when I was at Orion Air, we operated B747-100 for UPS. We had a celebration when the last -3 model engine was replaced by the so much better -7A models.