Navman101 wrote:

Sorry if this has already been discusses, but if so I couldn’t find it.

Does anyone know the rationale for the USAF choosing the PW4000 to power the KC-46 over the General Electric CF6-80. The USAF already operated the CF6 on many airframes such as VC-25, KC-10, and C-5M, so there would be at least some parts commonality. Was this a purely political decision to help keep Pratt and Whitney afloat? I suppose the Rolls Royce Power plant wasn’t even considered due to foreign sourcing.

Also what are peoples thoughts on which engine is actually better?

The Boeing Company has reached an agreement with Pratt & Whitney, a division of United Technologies Corporation, for the price and terms under which it will supply engines for the KC-767 Advanced Tanker. As a result, Pratt & Whitney becomes eligible to supply its PW4062 engines if Boeing is awarded the U.S. Air Force KC-X contract later this year.

"With more than 80 years of experience meeting the U.S. Air Force's engine needs, it makes sense to use Pratt & Whitney as an engine provider for the next generation tanker," said Ron Marcotte, vice president and general manager of Boeing Global Mobility Systems. "This high-performance, extremely reliable engine will allow future tanker aircrews to operate out of short-runway airfields and provide them maximum fuel offload performance."

Boeing's agreement with Pratt & Whitney followed a best-value competition that focused on engine technical requirements like enhanced thrust and fuel efficiency, as well as logistics support, acquisition and total ownership cost, management and past performance factors.

Although GE was originally considered to be a candidate for the KC-767 with the CF6-80C2 engine, or potentially even a variant of its GEnx, Boeing announced on 12 March that it has reached an agreement on the KC-X engine proposal with P&W and its PW4062.

P&W and Boeing had also teamed on an initial KC-767 lease proposal for the USAF in March 2004, but this agreement lapsed with the termination of the controversial plan. The two launch customers for Boeing's KC-767 tanker, Italy and Japan, meanwhile, selected the CF6-80C2 for their eight aircraft.

Although terms of the new Boeing/P&W deal have not been revealed, it is believed the engine maker offered attractive pricing based on the relatively low number of average flight hours expected to be accumulated by the average KC-X versus its nearest commercial equivalent.

Max Q wrote:

kc135topboom wrote:

Max Q wrote:

I just don’t know, I do know that looking through a piece of glass to look at the actual aircraft you’re refueling must be simpler, more straightforward and gives you the ‘real picture’


If it’s so complicated structurally to incorporate a boom operator station with a window then how has it worked so well for
decades on the KC135 and KC10 ?



It seems far simpler and effective to have a window than all the electronics involved with a remote viewing system, no big deal if you’re refueling with only probe and drogue but a different story altogether with the finesse required of a boom operator



But I’m no expert, there is one on this forum however, it would be interesting to hear TB’s take

A Boom Pod with a window is a much simplier arrangement and more reliable than being in a electronic closet. A window relies on the old Mk.-1 eyeball to work properly, an electronic closet filled with computers, sensors, and video game type controls can break down. Yes, I know these systems will have redundant back-up systems, but in some type of degrade such as some automation may not be available. This increases the Boom Operator's workload.

From a structual POV, incooperorating a Boom Pod into an airplane's structure is not a complicated engineering problem. Used aircraft such as the B-707 (KC-707, KC-137 Italy, Spain, Israel, Brazil, etc. were originally commercial airliners) and B-747 (IIAF KC-747s were originally TWA B-747-100s) have been modified with Boom Pods after their original build configuerations.

Thanks for adding a professional assessment


I’d like to see the boom operators station on the IIAF 747,I wonder if that’s a copy of the KC135 with the prone configuration or
similar to the KC10

tjh8402 wrote:

Navman101 wrote:

Sorry if this has already been discusses, but if so I couldn’t find it.

Does anyone know the rationale for the USAF choosing the PW4000 to power the KC-46 over the General Electric CF6-80. The USAF already operated the CF6 on many airframes such as VC-25, KC-10, and C-5M, so there would be at least some parts commonality. Was this a purely political decision to help keep Pratt and Whitney afloat? I suppose the Rolls Royce Power plant wasn’t even considered due to foreign sourcing.

Also what are peoples thoughts on which engine is actually better?

Per this (and other articles I could find on the subject), it was Boeing, not the USAF who made the call.

The Boeing Company has reached an agreement with Pratt & Whitney, a division of United Technologies Corporation, for the price and terms under which it will supply engines for the KC-767 Advanced Tanker. As a result, Pratt & Whitney becomes eligible to supply its PW4062 engines if Boeing is awarded the U.S. Air Force KC-X contract later this year.

"With more than 80 years of experience meeting the U.S. Air Force's engine needs, it makes sense to use Pratt & Whitney as an engine provider for the next generation tanker," said Ron Marcotte, vice president and general manager of Boeing Global Mobility Systems. "This high-performance, extremely reliable engine will allow future tanker aircrews to operate out of short-runway airfields and provide them maximum fuel offload performance."

Boeing's agreement with Pratt & Whitney followed a best-value competition that focused on engine technical requirements like enhanced thrust and fuel efficiency, as well as logistics support, acquisition and total ownership cost, management and past performance factors.

https://www.reliableplant.com/Read/5226 ... 767-tanker

This article hints it came down to $:

Although GE was originally considered to be a candidate for the KC-767 with the CF6-80C2 engine, or potentially even a variant of its GEnx, Boeing announced on 12 March that it has reached an agreement on the KC-X engine proposal with P&W and its PW4062.

P&W and Boeing had also teamed on an initial KC-767 lease proposal for the USAF in March 2004, but this agreement lapsed with the termination of the controversial plan. The two launch customers for Boeing's KC-767 tanker, Italy and Japan, meanwhile, selected the CF6-80C2 for their eight aircraft.

Although terms of the new Boeing/P&W deal have not been revealed, it is believed the engine maker offered attractive pricing based on the relatively low number of average flight hours expected to be accumulated by the average KC-X versus its nearest commercial equivalent.

https://www.flightglobal.com/news/artic ... ds-212666/

Runway28L wrote:

This appears to be the first ever hookup between a KC-46 and an F-35.

https://www.instagram.com/p/BtC0OKpgBzt/

The Boeing KC-46A Pegasus air tanker refuelled a Lockheed Martin F-35 Lightning II for the first time over California.

The tanker connected to the fighter aircraft with its refuelling boom on 22 January, marking the first time the Pegasus has refuelled a stealth aircraft, says the US Air Force. The KC-46A will also have to prove it can refuel the Lockheed Martin F-22 Raptor and Northrop Grumman B-2 Spirit.

Refueling a stealth fighter or bomber is more difficult than a conventional aircraft because the tanker’s boom operator must avoid scratching the stealth coating on the outside of the aircraft. If the aircraft’s special coating is scratched it could increase its radar visibility.

Refuelling an F-35 signifies Phase III of the USAF’s testing of the KC-46. Phase III is the final stage of developmental testing, is planned to last 15 months and is being conducted out of Edwards Air Force Base, California.

The USAF formally accepted the first KC-46A from Boeing on 10 January after more than a year-and-a-half delay, caused by an assortment of manufacturing and regulatory issues.

The KC-46A has had problems with its remote vision system; a combination of stereoscopic and infrared cameras that provide a 185° field of view behind the tanker and help an onboard operator steer the refueling boom into contact with a receiver aircraft. The remote vision system’s most recent problem is a sunlight glare issue that occurs when the tanker is flying directly away from the sun.

However, Boeing argues that the programme has turned a corner and notes that the system is only impacted by sun glare problems about 3% of the time. Ultimately, showing that the KC-46A can precisely refuel stealth aircraft, such as the F-35, is an important step for reestablishing confidence in the remote vision system.

Ozair wrote:

Because I have no idea and Flight Global used the term interchangeably in the article above, is there a convention on using the term refuelling or refueling? English versus American spelling?

kc135topboom wrote:

Max Q wrote:

kc135topboom wrote:

A Boom Pod with a window is a much simplier arrangement and more reliable than being in a electronic closet. A window relies on the old Mk.-1 eyeball to work properly, an electronic closet filled with computers, sensors, and video game type controls can break down. Yes, I know these systems will have redundant back-up systems, but in some type of degrade such as some automation may not be available. This increases the Boom Operator's workload.

From a structual POV, incooperorating a Boom Pod into an airplane's structure is not a complicated engineering problem. Used aircraft such as the B-707 (KC-707, KC-137 Italy, Spain, Israel, Brazil, etc. were originally commercial airliners) and B-747 (IIAF KC-747s were originally TWA B-747-100s) have been modified with Boom Pods after their original build configuerations.

Thanks for adding a professional assessment


I’d like to see the boom operators station on the IIAF 747,I wonder if that’s a copy of the KC135 with the prone configuration or
similar to the KC10

I have never seen the Boom Pod in the IIAF KC-747s. I have seen a picture taken of the Boom Pod from outside, with the siting door open. The siting window appears about the same size as the KC-135, KC-707/KC-137. That leads me to believe it is the same as the KC-135s interior Boom Pod and instrument panel and Boom controlsand systems. The Boom fitted to the KC-747s and thier KC-707s is the same as the KC-135 Boom.

Moose135 wrote:

Ozair wrote:

Because I have no idea and Flight Global used the term interchangeably in the article above, is there a convention on using the term refuelling or refueling? English versus American spelling?

The KC-135A Dash-1 flight manual I have (as well as the accompanying "Air Refueling Procedures" manual) spell it with one "L" as refueling.

Revelation wrote:

zanl188 wrote:

kc135topboom wrote:

A Boom Pod with a window is a much simplier arrangement and more reliable than being in a electronic closet. A window relies on the old Mk.-1 eyeball to work properly, an electronic closet filled with computers, sensors, and video game type controls can break down. Yes, I know these systems will have redundant back-up systems, but in some type of degrade such as some automation may not be available. This increases the Boom Operator's workload.

From a structual POV, incooperorating a Boom Pod into an airplane's structure is not a complicated engineering problem. Used aircraft such as the B-707 (KC-707, KC-137 Italy, Spain, Israel, Brazil, etc. were originally commercial airliners) and B-747 (IIAF KC-747s were originally TWA B-747-100s) have been modified with Boom Pods after their original build configuerations.

Then why, after many years of development and billions spent, did USAF not specify a boom pod? Surely USAF knows what it needs and had sufficient clout to get exactly that.

Maybe a 'gee wiz' factor took over?

Maybe it was thought since this is all being done in the digital domain, we can train the boom operators with simulators using real data captured from actual operational sorties and thus gain training efficiency, whereas it's hard to do that well with the older technology.

Maybe they view the digital approach as the gateway to eventual computer AI driven refueling and eventual elimination of the boom operator.

bikerthai wrote:

Question. Isn't the current KC-30 remotely operated? We do not hear issues about that system. Perhaps they work the same, it's just that the Air Force was expecting more from the KC-46 version.

bt

scbriml wrote:

Moose135 wrote:

Ozair wrote:

Because I have no idea and Flight Global used the term interchangeably in the article above, is there a convention on using the term refuelling or refueling? English versus American spelling?

The KC-135A Dash-1 flight manual I have (as well as the accompanying "Air Refueling Procedures" manual) spell it with one "L" as refueling.

The single L is an American thing. Just about the rest of the entire English speaking World uses LL (and fewer Z's but a lot more S's )

scbriml wrote:

The single L is an American thing. Just about the rest of the entire English speaking World uses LL (and fewer Z's but a lot more S's )

Boeing leadership was forced to ground its 767-based KC-46 tankers for the past week after the Air Force expressed concern about loose tools and other foreign object debris (FOD) found in various locations inside the completed airplanes, according to internal company memos.

“We have USAF pilots here for flight training and they will not fly due to the FOD issues and the current confidence they have in our product that has been discovered throughout the aircraft,” factory management wrote in a memo a week ago to employees on the 767 assembly line.

“This is a big deal,” the memo emphasized.

On Thursday, Boeing spokesman Chick Ramey acknowledged the problem but characterized it only “a temporary pause” in flight operations. He said training flights are set to resume Thursday after approximately a week’s downtime, during which Boeing worked with the Air Force on how to resolve the production problems.

The KC-46 is built as an empty 767 airframe on the main assembly line in Everett, then transferred to a facility at the south end of Paine Field called the Military Delivery Center (MDC), where the jet’s military systems, including the refueling and communications equipment, are installed and the airplanes are completed.

The internal company memo said the MDC “grounded our 767 tankers due to FOD and tool control.”

During the process of building aircraft, all airframes are supposed to be routinely swept for any kind of foreign object debris — especially anything metal. A loose object left, say, inside a wall cavity or under a floor, is potentially dangerous because over time it could damage equipment or cause an electrical short.

“The 767 program has been scrambling to get our employees down south … to the MDC to clean FOD from our delivered tankers to get our aircraft back in the air,” the memo states.

The memo notes that eight tools were found in aircraft delivered to the MDC and two more in tankers delivered to the USAF.

Another memo said repeated finding of FOD by the Air Force was “a chronic issue” that has “resulted in a program level impact.”

Air Force spokeswoman Capt. Hope Cronin said the military is “aware of the concerns over FOD in KC-46 production aircraft” and takes such contamination “very seriously.”

“The combined Air Force, Defense Contract Management Agency, and Boeing team is working together to resolve these concerns as safely and quickly as possible,” Cronin said via email.

Making sure that no FOD makes its way onto a finished airplane is the responsibility of every mechanic who works on the plane but also of the quality inspectors, whose job is to do a final check on any area of an airplane before it is closed up.

What seems to be a serious lapse in FOD control comes as Boeing says it intends to cut almost 1,000 Quality Inspectors jobs over the next two years.

Quality inspectors concerned about that move pointed recently to Boeing’s failure in December of one element of a quality control audit on the 747, 767 and 777 airplane programs.

Management said the MDC “has declared a level 3” state of alert on the Everett assembly line over the KC-46 FOD issue. On a scale embedded in Boeing’s defense contracts, this is a level that the memo makes clear is one step away from a complete shutdown of the assembly line.

“Does anyone know what a level four is?” the management memo asks. “A level four … will shut down our factory. This is a big deal.”

Employees installing the airplane’s systems on the assembly line were directed last week to shut everything down “48 minutes prior to shift end” in order to complete a thorough inspection for FOD and to clean the work area.

“It will take us all to win back the confidence of our customer/USAF and show them that we are the number one aircraft builder,” the memo urges.

In addition to six flight test KC-46 tankers, Boeing has already delivered six tankers to the McConnell and Altus Air Force Bases so far, with about 45 more production tankers at Boeing’s Puget Sound area facilities in the final stages of completion.

Ozair wrote:

Boeing tanker jets grounded due to tools and debris left during manufacturing

Moose135 wrote:

Ozair wrote:

Boeing tanker jets grounded due to tools and debris left during manufacturing

"Buy a tanker, and we'll throw in this free wrench!"

with about 45 more production tankers at Boeing’s Puget Sound area facilities in the final stages of completion.

EK77WNH wrote:

I read that Pease here in New Hampshire was going to be rid of all their KC-135R's by the end of this month, even though the first KC-46 isn't due there until September or October. Does that compromise the mission at Pease, or are there enough assets around in the northeast to handle it all?

EK77WNH wrote:

I read that Pease here in New Hampshire was going to be rid of all their KC-135R's by the end of this month, even though the first KC-46 isn't due there until September or October. Does that compromise the mission at Pease, or are there enough assets around in the northeast to handle it all?

Spacepope wrote:

So, only one delivery in March, they’re about 4 behind (revised) schedule now. Is there another holdup beyond the FOD issues?

The Air Force has once again halted deliveries of the KC-46 Pegasus tanker from Boeing after more foreign object debris, or FOD, was found in some closed compartments of the aircraft.

Air Force Secretary Heather Wilson confirmed in a House Armed Services Committee hearing on the budget Tuesday morning that deliveries had been stopped for a second time. Wilson told Rep. Joe Courtney, D-Conn., that the Air Force is putting corrective actions in place, including requiring all closed compartments be inspected, “to make sure that the production line is being run the way that it needs to be run.”

Courtney expressed concern that problems with the KC-46 appear to be getting in the way of the Air Force’s “optimistic projections” about delivery of the aircraft.

Air Force spokeswoman Ann Stefanek said in an email that the decision to stop accepting the KC-46s was made on March 23. But inspectors are still finding debris and other quality problems with the Pegasus, as recently as this week, she said.

“The Air Force again halted acceptance of new KC-46 tanker aircraft as we continue to work with Boeing to ensure that every aircraft delivered meets the highest quality and safety standards,” Stefanek said. “This week our inspectors identified additional foreign object debris and areas where Boeing did not meet quality standards.”

Stefanek said the problems are not related to the aircraft’s design or engineering specifications. Boeing has so far delivered seven KC-46s to the Air Force.

“Air Force leadership is meeting with Boeing to approve additional corrective action plans before aircraft acceptance can resume,” Stefanek said.

In another budget hearing Tuesday afternoon, with the House Appropriations subcommittee on defense, Wilson said that problems with foreign object debris can range from a dropped wrench that gets left behind, to small pieces of aluminum left on surfaces. But if surfaces don’t get wiped down to clean off those aluminum fragments, they can get in the middle of things and cause serious problems in the aircraft, Wilson said.

Most recently, Wilson said, inspectors opened up closed compartments, such as those inside wings, to see if they had been wiped down. Those areas were better than some of the open areas, she said, “but they weren’t what we would expect.”

“That is a manufacturing discipline issue, on the line ... and we saw a breakdown there,” Wilson said. “We expect excellence in the manufacture of our aircraft, and we are working with Boeing on corrective action plans.”

Boeing said in a statement Tuesday that fixing this problem is a top priority for the company and the program.

“Boeing is committed to delivering FOD-free aircraft to the Air Force,” Boeing spokesman Charles Ramey said. “Although we’ve made improvements to date, we can do better.”

Ramey said Boeing is conducting additional company and customer inspections of the aircraft, and have put preventative action plans in place. Boeing has also added more training, put more rigorous clean-as-you-go practices into place, and is holding FOD awareness days across the company “to stress the importance and urgency of this issue.”

“Safety and quality are our highest priority,” Ramey said.

The Air Force on March 1 confirmed that it had suspended deliveries the first time because tools and other debris had been left in the planes, which could be a safety hazard. By that point, six tankers had already been accepted by McConnell Air Force Base in Kansas and Altus Air Force Base in Oklahoma.

Deliveries resumed March 11, after more than two weeks, when the seventh Pegasus arrived at Altus. The Air Force had received Boeing’s corrective action plan, and said it would closely scrutinize plans before accepting them.

U.S. Transportation Command said last month that it is preparing to delay the retirement of some KC-135 tankers, which are intended to be replaced by the KC-46, due to the problems and delays with the Pegasus’ deliveries. Technical problems had already delayed delivery of the first tanker more than two years from when it was originally expected.

JayinKitsap wrote:

I though that after the 1st FOD issue, Boeing would have opened up every compartment and checked it, now it will be a real big deal getting each accepted.

I would suspect the after the line work being the cause, what is the QC on production wing tanks and compartments?

747classic wrote:

The U.S. Air Force will begin accepting Boeing KC-46As later this month (April)

Boeing ‘Embarrassed’ By KC-46A Debris Problems.

See : https://aviationweek.com/defense/usaf-b ... s-problems

bikerthai wrote:

The difference between the P-8A and the KC-46 was the Navy was lucky enough to planned for sufficient time for product development and there was no mishaps as large as the wiring rework on the KC-46. There were incidents, but nothing systemic.

bt

Ozair wrote:

Lucky…. I’m not sure why you can claim that.

Johnv707 wrote:

JayinKitsap wrote:

Is there a list somewhere of the production and deliveries of the KC-46 (also P-8's) like other aircraft have. So far I know that 5 are delivered and I heard around Christmas that 10 were basically ready. I recall reading that there would be 4 in Jan (met), 4 in Feb, then 3 per month after that.

LOOK HERE: https://docs.google.com/spreadsheets/d/ ... 2121076296

Runway28L wrote:

Image of the new hangar going up at the 916th Air Refueling Wing which will be receiving their first of twelve KC-46s in the coming months.

Moose135 wrote:

Hope they have the insides open to the public, that will be interesting to see.

Ozair wrote:

Moose135 wrote:

Hope they have the insides open to the public, that will be interesting to see.

Careful where you step, there might be some excess material left around…

Max Q wrote:

kc135topboom wrote:

Max Q wrote:

Thanks for adding a professional assessment


I’d like to see the boom operators station on the IIAF 747,I wonder if that’s a copy of the KC135 with the prone configuration or
similar to the KC10

I have never seen the Boom Pod in the IIAF KC-747s. I have seen a picture taken of the Boom Pod from outside, with the siting door open. The siting window appears about the same size as the KC-135, KC-707/KC-137. That leads me to believe it is the same as the KC-135s interior Boom Pod and instrument panel and Boom controlsand systems. The Boom fitted to the KC-747s and thier KC-707s is the same as the KC-135 Boom.

Thanks TB, what is the ‘siting door ?’