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More KC-46A woes....

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More KC-46A woes....

Old 31st May 2017, 06:31
  #601 (permalink)  
 
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KenV,

How much different is the US version of the tanker to the Italian or Japanese? I would have thought the US version and the Italian would share many specification - maybe as a part of the NATO specification.
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Old 31st May 2017, 13:58
  #602 (permalink)  
 
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From memory, the Italian and Japanese aircraft are basically 767-200ERs with the current (KC10?) flying boom. The KC46 is a 200F airframe with 300F floor and cargo door and -400 series digital cockpit, alongside a new version of the flying boom (Hence the 'Frankentanker epiphet that some detractors use)
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Old 31st May 2017, 16:04
  #603 (permalink)  
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The USAF have a requirement for the KC-46A to operate far closer to a threat environment than virtually every other tanker nation. Hence the requirements for systems redundancy, including cable runs etc. are more severe for the KC-46A Pegasus than for the KC-767I or KC-767J.

The KC-46A is also intended to be used as a 'smart tanker', with an associated need for clever comms kit etc., but this isn't a feature of the KC-767I or KC-767J.

A lot of programme delay for the Italian tanker was down to buffet and flutter problems caused by the pods/pylons. Whereas the KC-767J has the 'old-style' boom rather than the latest generation version fitted to KC-46A; the KC-767J is not fitted with wing AAR pods, hence introduction into service with the JASDF was achieved very quickly.
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Old 31st May 2017, 16:24
  #604 (permalink)  
 
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Originally Posted by ImageGear View Post
Even if, as they should have been, all the bases had been covered during the design process, do you believe that the project still had the potential to be successful (Within the definition of success) for the USAF?
"had the potential"? In my opinion, it STILL has the potential to be successful and very likely will be. A one year delay does not a failure make.
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Old 31st May 2017, 16:41
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Originally Posted by Rwy in Sight View Post
KenV,How much different is the US version of the tanker to the Italian or Japanese? I would have thought the US version and the Italian would share many specification - maybe as a part of the NATO specification.
Quite a bit different. KC-767 was based on 767-200ER. Indeed they were built as 767-200ER and then flown to a mod center where they were modified to tanker configuration. KC-46 is based on the 767-200LRF (Long Range Freighter) which has -200ER fuselage, -300F wing, landing gear, cargo door and floor, -400ER avionics with 787 displays, different refueling boom (KC-10 advanced refueling boom vs KC-135 refueling boom) and different WARP (wing aerial refueling pods) than Italian tanker (Japanese tanker had no WARP). And about 25 miles of additional wiring to accommodate new USAF "smart tanker" requirements. The combination above is why some apply the absurd "frankentanker" epithet to the KC-46.
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Old 31st May 2017, 17:38
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A complex certification too (as if any certification is simple). Show compliance for FAA certification of the 767C amended type design, for certification of the supplemental type design (installations of all the "tanker" items) and military certification of the many GFE bits and pieces for which there are no FAA criteria and which may be classified. And there's the Plan for certification and the actual Execution, which require many iterations to reconcile. These were all part of the USAF requirements and Boeing proposal the USAF selected.
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Old 31st May 2017, 18:28
  #607 (permalink)  
 
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Originally Posted by stilton View Post
The 767 RAT provides hydraulic power to the flight controls in the event of a dual
engine flameout.

It does not provide any electrical power.
Correct - the 767 battery is certified to supply critical electronics for 30 minutes (which in the case of an all engine power loss is considered to longer than a 767 would be able to glide).
However the hydraulics can supply some electrical power via the HMG (HydroMechanical Generator). I don't believe early 767s had an HMG basic, it was added as part of the ETOPS package.
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Old 20th Sep 2017, 17:54
  #608 (permalink)  
 
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KC-46A testing glitches could delay USAF tanker milestone

Article on Flight Global:-

(Snip)
Despite earlier assurances that Boeing would deliver the US Air Force's first 767-based KC-46A tanker by the end of this year, boom scraping issues and a slew of uncompleted test points may delay delivery until 2018, the head of its Air Mobility Command has revealed.

More than half way into testing, the USAF has discovered severe flaws on the tanker, known as “category 1 deficiencies”. Among the most glaring, the tip of its boom has on occasion struck receiver aircraft outside their refuelling slipways. Boeing engineers are working to fix the problem, but unless the issue is resolved it could delay a scheduled 1 December delivery, Gen Carlton Everhart said at the annual Air, Space and Cyber conference near Washington DC.

Hmm, that could put a dent in things...
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Old 20th Sep 2017, 18:44
  #609 (permalink)  
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Or at least take the shine off them....
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Old 20th Sep 2017, 19:37
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IMHO- having been on the initial 767 production in the early 80's- andalso worked on b1 and b2 programs - somewhat aware of the first 767 tankers fiasco and how it happened -and still knowing many current BA employees- the simplest explanation for FUBAR issues relates to miss- management, MDC- st louis types- Jack welch wannabees, and a focus on faster better cheaper mantra.

Note that the military versions of the 737 series, incuding very successful Navy p-8 program was run primarily by old commercial types with minimum interference by the ex MDC fighter jock types. Not so for the 2001-2003 767 tanker fiasco, the 787 cluster**, the dash 800 737 wing design types( ex MDC ) who stalled for a few years the Aviation partners winglet improvements now standard on most aircraft.
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Old 20th Sep 2017, 21:29
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Oh dear, what a pity, how sad, p*** up in a brewery, springs to mind.
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Old 21st Sep 2017, 06:23
  #612 (permalink)  
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Having to turn off the HF when tanking is a deficiency? It was always considered a prudent safety precaution in years past. As for the camera, the Dutch KDC-10 has managed using a similar system for many years, as have various Airbus types, so I don't see the inadequacy of current camera technology being the root of the problem.

The issue of undemanding boom extension could be an embarrassment or a danger depending when it happens....



NATIONAL HARBOR, Maryland—Boeing is looking at upgrading the camera systems used for aerial refueling on its new KC-46 tanker after the U.S. Air Force discovered the refueling boom can scrape and potentially damage receiver aircraft.

The remote air refueling observatory cameras in the new Pegasus tanker were the best the market offered in 2012 when the aircraft was being contracted, but is not the latest technology, Air Force spokesman Col. Christopher Karns told Aviation Week Sept. 20th. Boeing would assume the cost of upgrading the camera system, Karns said. A Boeing spokeswoman declined to comment.

The problem involves the KC-46’s rigid refueling boom, one of two systems it has to refuel aircraft in flight. As the tanker’s boom goes into the receiver aircraft, the device has a tendency to scrape the surface of the receiving aircraft, explained Gen. Carlton Everhart, commander of Air Mobility Command, on Sept. 20 during the Air Force Association’s annual Air, Space and Cyber conference here. This could pose a particular problem for stealth aircraft such as the B-2 bomber, F-22 or F-35 fighters, if the boom causes damage to low-observable stealth coating, officials acknowledge. The KC-46 has not yet refueled stealth aircraft during flight testing, Boeing spokeswoman Caroline Hutcheson said.

The KC-46’s other refueling system, the Centerline Drogue System (CDS), also has a tendency to leave scuff marks on the tanker itself. The CDS consists of a flexible hose that trails from the tanker aircraft and a “drogue” fitted to the end of the hose that acts as a funnel to aid insertion of the receiver aircraft “probe” into the hose. This refueling method is also called “probe-and-drogue” or “hose-and-drogue.” The drogue flies well, but contacts the airframe when being reeled in, leaving “witness marks” on the aircraft’s body, Air Force KC-46 System Program Manager Col. John Newberry says. “When you retract it and bring it in, it comes up and rubs across the bottom of the aircraft,” Newberry told Aviation Week in a Sept. 19th interview. Everhart said this is a more minor issue compared with the boom scraping problem. Newberry said the solution could be as simple as requiring closer inspections of that section of the airframe and applying touch-up paint because the Air Force does not want to redesign the drogue system over a few scuff marks.

The boom scraping issue is one of three significant—or “category one”—deficiencies the Air Force-Boeing team is trying to fix on Boeing’s new tanker, Lt. Gen. Arnold Bunch, the service’s top uniformed acquisition official, said Sept. 20 during the conference. The KC-46 is also having problems with high frequency (HF) transmission, during which the HF “turns off” when the aircraft goes into aerial refueling mode, Bunch said. The third issue is “uncommanded boom extension,” he said, which seems to mean the boom unexpectedly extends when it is not supposed to do so. The Air Force did not provide a more detailed explanation by press time.

Boeing’s engineering team and the program office are working hard to fix all three problems, Bunch said.
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Old 22nd Sep 2017, 13:41
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"Scuff marks"???????
They mean collision don't they...........
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Old 23rd Sep 2017, 10:34
  #614 (permalink)  
 
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A little more background on the problems:-
KC-46 Problems Should Not Add Delays; Possible Boeing Cost Rise: BG Shipton « Breaking Defense - Defense industry news, analysis and commentary

Sent from my iPad Mini.
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Old 16th Oct 2017, 17:14
  #615 (permalink)  
 
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Not so much woes....a little progress perhaps...????

https://www.flightglobal.com/news/ar...kc-46a-442104/
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Old 16th Oct 2017, 18:34
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Drogue contact on a fuselage during trailing/winding has been a routine on many tankers. However, allowing for interested party understatement, maybe the issue here is more serious?

OAP
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Old 17th Oct 2017, 10:48
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Yes - that's what surprised me - I wonder if it's scraping off some stealth coating or similar??
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Old 17th Oct 2017, 13:20
  #618 (permalink)  
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Drogue scrapping presumably being much gentler than boom scrapping....
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Old 18th Oct 2017, 06:06
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The issue seems to be the want of a more advanced system for boom refueling then was in specs. The old system was deemed fine for non stealth aircraft but they have stealth aircraft now. That have a more fragile coating that can be disturbed by old type of refueling. But what do you know there are new active control booms that will fix that problem. Just a question of who is going to pay for it. The Air Force are Boeing I guess they will be some rather careful readings of the contract by both side to figure it out.
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Old 18th Oct 2017, 06:36
  #620 (permalink)  
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ORAC wrote:
Having to turn off the HF when tanking is a deficiency? It was always considered a prudent safety precaution in years past.
Not quite. It was only necessary to deselect HF transmitters during AAR, but there was no restriction on receiving provided that any 'auto tune' of the antenna was disabled so that changing receiver frequency did not cause any transmissions as the antenna tuning unit matched the antenna to the new frequency - as was the case with the early HF system in the VC10K before 'auto / man' HF tuning was fitted.

Another stupid HF design in a different tanker turned off the receiver audio when SELCAL was selected on. Which made it impossible to conduct a normal SELCAL check with the ATCC.... Which bright designer thought up that idea?
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