RSAF tanker replacement?

weasel1962 SG

Aviationweek is reporting that RSAF is interested in replacing its KC-135 tankers. These aircraft were purchased from US under the EDA program for US$2.3m each and then re-engined for modern fuel efficiency. The KC-135s, built between years 1959 to 1963 are 48-52 years old but are estimated by GAO to be capable of 80+ years of operations. These tankers may not be the oldest aircraft in RSAF inventory, a 1958-built C-130B may continue hold that record esp with a recent ST upgrade.

http://www.aviationweek.com/aw/generic/story.jsp?id=news/asd/2011/07/29/01.xml&headline=Asians, Europeans Seek Aerial Refuelers&channel=defense

The tankers were transferred in years 1997-1998 and entered full operations under RSAF service in year 2000. For the past 11 years, these have performed sterling services and participated in many overseas deployment such as in the gulf as well as fuelled fighter redeployments from the US.

The age of the aircraft has continually fuelled rumours that the RSAF is on the look-out for replacements. Not surprising as the older the aircraft, the higher the operational cost. However any replacement will need to fulfil the capabilities currently performed by the KC-135. Moreover, with the higher fuel requirement of the new F-15s over the older F-16 fighters, this places greater burden on the already stretched KC-135. The article proposes 3 options. A conversion of a KC-767. A KC-46 purchase. An airbus A-330 purchase. All 3 options involve aircraft which will exceed KC-135 capabilities. However I have decided to do a more detailed analysis.

For conversion, Singapore Technologies actually has experience with freighter conversions, a first step for tanker conversion. The problem is that neither Silkair or SIA operates Boeing 767 or has any in inventory. This will require a 2nd hand purchase. It is unclear if the RSAF wants to operate another 2nd hand aircraft as a replacement.

For newbuilt KC-46, the article highlights that RSAF is unlikely to select KC-46 as USAF takes up all the production slots. This, however, does not consider if the RSAF can negotiate to take up USAF production slots as the RAAF had done with their F-18 SH purchase. However, more importantly is that few in Singapore is certified to fly a Boeing 767 due to SIA/Silkair non-operation. This will add to cost as training will need to be done.

For newbuilt A-330, critically, EADS lost the tanker battle and this affects economies of scale. However, commercial airbus sales have taken off and how that impacts the pricing may be critical. It is very clear that the A-330 is more expensive than the 767 on an airframe to airframe comparison though EADS & their supporters will argue that it may be more efficient on a lb per lb carried basis. Funnily enough, SIA & Silkair don’t operate A-330s either but A-320s.

Other options that have been floated include a G-550 tanker version that does not appear to have gotten off the design board. Also, a KC-777 version that though suggested has not materialised. The latter should be of particular interest to the RSAF as SIA has many 777s in reserve that can be converted to tankers should this be accepted. If Boeing agrees to the tanker conversion performed by Singapore Technologies, this would expand ST’s capabilities and with the benefits for the local market, the commercial benefit should be appealing. Although a new build 777 (list: US$232-269m) is far more expensive than a 767 (list: US$144-180m), 2nd hands might be a fraction of a 767 price. SIA, as the 5th largest operator of the 777, has started to retire some of its 777 all of which are extended range variants. Procured from 1999, the 777 still have plenty of life left from a military standpoint rather than a commercial one (where SIA’s strategy is to only operate aircraft in its early life). With servicing, maintenance and pilot availability not an issue, a KC-777 has many strong points for RSAF service inception.

An analysis of RSAF fuel requirements appear to suggest that the KC-135s can already keep a substantial part, but not its entire fighter fleet, of the RSAF fleet continuously in the air. The KC-777 can offload 45% more fuel than the KC-767, 23% more than the A-330 and a whopping 78% more than the KC-135 and may be able to do so. Ultimately, it boils down to RSAF needs. Whilst overseas deployments are an important element of RSAF service, the much smaller KC-135 has appeared to be more than sufficient at this juncture. Also, other than a small contingent of fighters in the US, such a fuel requirement may not be as large as some might require. With new fighters carrying much more fuel (and fuel tanks), the necessity for aerial refuellers diminishes. More importantly, stealth fighters are beginning to enter service and such fighters increases operational risks to traditional refuelling operations/aircraft. It would be interesting to see what the RSAF chooses.

alize SG

Qns for you:

Is it the absolute cost, or the cost per pound of fuel capacity that is more important?

Are the unrefuelled range and endurange of RSAF fighters sufficient for their wartime offensive and defensive missions, and is it correct to say tankers will largely support peacetime needs?

In wartime, is tanking worthwhile given proxmity to hostile territory?

However, more importantly is that few in Singapore is certified to fly a Boeing 767 due to SIA/Silkair non-operation. This will add to cost as training will need to be done.

Does RSAF draft pilots (including ex-regular pilots with reservist obligations) back into service?

weasel1962 SG

Qns for you:

Is it the absolute cost, or the cost per pound of fuel capacity that is more important?

Are the unrefuelled range and endurange of RSAF fighters sufficient for their wartime offensive and defensive missions, and is it correct to say tankers will largely support peacetime needs?

In wartime, is tanking worthwhile given proxmity to hostile territory?

Q1: Depends. In the USAF case, they were historically averaging 50-60k of fuel offload. That's not going to change drastically with the KC-767 even though that aircraft can carry more fuel. So anything more is excess. The airbus people thought they could change this thinking but every aircraft big or small now has only 3 points to refuel so the rate of offload is still limited. I don't have rsaf figures so not in the position to state whether the KC-135 has been sufficient, under-utilised or insufficient.

Q2 : Agree existing fighters have unrefuelled range sufficient for RSAF purposes. CAS won't be required beyond 400km, alpha strikes not expected beyond 600km. Fighter escort not beyond upper limit and CAP definitely within.

Q3: Definitely. CAS requires endurance eg Libya where targets of opportunity only crops up after long hours of flight. Air tankers also improve sortie rates eg fighters that still have unexpended ammo doesn't need to land & refuel. Just tank up and continue the CAP or the next escort. This makes sortie rates more efficient esp when there are many aircraft operating from few airfields. In SG's case its about endurance than range. That's why even though sortie distances are likely to be low in wartime, F-15s and F-16s are still fitted with CFTs & external tanks.

alize SG

Q1 A larger tanker is useful for global air mobility and strike missions (not useful here). Btw, RSAF KC-135s do not have a receptacle of their own.

Q3 I'm wondering if the risks of tanking in proximity to threats are worth it. At the current time there is little threat, but that can easily change with SAMs like the S300 (and its Chinese copies. But as it is, Msia is only looking a rather backward-looking SAM called the KS1, said to be in the HAWK class). It will take longer for adversaries to build more airbases but when they do, there will be no shortage of landmass to do so.

weasel1962 SG

RSAF will not tank in risk areas. No one does.

Any MR-SAM that is deployed within 50-100km will be under continuous surveillance from UAVs and I’m not too concerned about that. With laser designation, visual etc, too many assets eg Himars et al, to take it out. That’t not to mention that it’d be operating under intense EW. It’s already easier to deploy an Anza at the border to take out aircraft taking off. That’s definitely within its 5 km range.

Commercial airlines will put pressure on the MY govt to avoid such deployments as well. No one wants a potentially loose cannon anywhere near commercial flights. Think about it, how easy is it to distinguish a KC-135 from a commercial boeing or airbus flight using radar…even the US shot down a 747 once in error. That’s why visual ID is still the roe.

alize SG

RSAF will not tank in risk areas. No one does.

I'm assuming in war we won't be tanking or operating a mere 5km from the FEBA. Even with UAVs with longer range than the current ones (100km), you have to prevent them being shot down (presumably by forward deployed, shorter range SAMS in order to keep the S-300s hidden).

How useful is it to tank if one must transit to and from the front line to a rear area to do it?

From the oldest (Vietnam) to the most recent (Libya) tanker war, the enemy was either beyond the aircraft's range (eg beyond jungle or ocean), lacked an air defence system (Iraq, Afghanistan) or both. I believe where these factors are not met, tanking for CAS might not be viable.

weasel1962 SG

Short-ranged sams can’t reach where the Heron/Hermes goes. If a MR-SAM’s radar start emitting, there’s more than enough sensors to detect it. 50km should be well-within sniper pod & UAV visual range and missiles don’t fire at max-range.

The UAV will stand-off. The location will be confirmed and double checked. The second a shooting war starts, prime target. When its taken out, then the tankers go up or come back.

The sensor-shooter cycle for a Himars is actually pretty short in practice. The 70km sniper is more than sufficient for the job. Even if not, the army will push across the border to establish a safe zone. If the army can’t do that, then all the tankers in the world won’t make a diff.

alize SG

The UAV will stand-off. The location will be confirmed and double checked. The second a shooting war starts, prime target. When its taken out, then the tankers go up or come back.

destroyed like Syria's SA-6s...

weasel1962 SG

Decided to share some numerical calculations on tanker offloads. Assuming fuel 80% of internal fuel tank with 20% reserve.

1 x KC-135R can refuel 22 x F-16s or 12 x F-15s at 500nm, 3 at a time.

1 x KC-767 can refuel 23 x F-16s or 13 x F-15s at 500nm, 3 at a time.

1 x KC-777 can refuel 39 x F-16s or 21 x F-15s at 500nm, 3 at a time.

No 500nm figures for A-330 MRTT but it should be mid-way between KC-767 & KC-777. Sorties are unlikely to exceed 500nm although the F-15SG has a combat radius of 1000+nm.

RSAF has ~60 F-16s and 24 F-15s. F-5s not counted (1 KC-777 can fuel ~63 F-5s which is more than what RSAF has...).

The difference for offload is at range. The KC-135R can only fuel 6 x F-16s at 2500nm. The KC-767 can fuel 14 x F-16s at 4000nm whilst the KC-777 can fuel 30 x F-16s at 5000nm. Since rsaf do not deploy that many fighters overseas, this may not be a factor.

The F-35A/B, if it enters service, may make a difference to the above. The F-35A carries 2.5+ times the fuel of an F-16. This means it can roughly do 2 sorties to 1 for an F-16 at the same combat radius without refuel. However, if it does do a refuel, it will need 2.5 times the requirement stated above.

Rough indicative numbers suggest a KC-767 will cost ~US$200m each, KC-30 = ~$300m & KC-777 = ~US$400m each.

Susanteo2011 SG

aiyoh..................no wonder GST keep going up lah...............

touchstone_2000 SG

If SG were to step into the pis** over the Spratly Islands, , wouldn’t all the planes need to refuel?

Say a peace keeping mission.

weasel1962 SG

Not if it based in MY or Brunei which would likely be the case if it actually intervened.

If not, the F-15s have the range to reach there. Distance to Sepanggar bay ~785nm, F-15SG has 1000 nm combat radius :)

But SG has zero reason for intervening.

spartan_6 SG

SIA do operate A330, i was an ex-SIAEC tech

spartan_6 SG

If we choose P-8 as e F-50 MPA replacement, a B767 tanker might well be likely

leewan SG

Yup. SIA has been operating the A330 for a few years already. But they are all a few years old which rules out any conversions. And there are various air forces around the world that are already operating the tanker version of the A330.

Isn't it time RSAF found a replacement for the C130 ? They have been in the air force for ages. The KC 135 was a replacement for the tankering version of C130 10 years back.

alize SG

For newbuilt KC-46, the article highlights that RSAF is unlikely to select KC-46 as USAF takes up all the production slots. This, however, does not consider if the RSAF can negotiate to take up USAF production slots as the RAAF had done with their F-18 SH purchase. However, more importantly is that few in Singapore is certified to fly a Boeing 767 due to SIA/Silkair non-operation. This will add to cost as training will need to be done.

What is the significance of this statement?

alize SG

Not if it based in MY or Brunei which would likely be the case if it actually intervened.

If not, the F-15s have the range to reach there. Distance to Sepanggar bay ~785nm, F-15SG has 1000 nm combat radius :)

But SG has zero reason for intervening.

Do you mean base in Sepangar or bomb it? Sepangar has no runway.

(1000nm is the very maximum combat radius with CFT and drop tanks.)

weasel1962 SG

SIA do operate A330, i was an ex-SIAEC tech

Thanks for the info. Noted that SIA leases A330s.

weasel1962 SG

What is the significance of this statement?

Nothing more than what's stated.

Do you mean base in Sepangar or bomb it? Sepangar has no runway.

(1000nm is the very maximum combat radius with CFT and drop tanks.)

Sepanggar Bay is nothing more than a yardstick ie how far the F-15SG can operate. There are runways nearby eg Kota Kinabalu which can be used by RSAF if MY allows...maybe Limbang (shorter) as well. For RMAF, there's Labuan airbase & Kuching which is the main airbase for the RMAF that is a little further out. Directly on Layang Layang, known to avid divers, is a 1000m airstrip as well.

1000nm is unrefuelled combat radius. It can go much further with air refuel .

weasel1962 SG

Isn't it time RSAF found a replacement for the C130 ? They have been in the air force for ages. The KC 135 was a replacement for the tankering version of C130 10 years back.

One of the previous air force chiefs ruled it out in the near term. Methinks after ST avionics upgrade, the charlies will continue for awhile longer.

F-50 only 14 years from OC. Can fly a lot longer (though most MPA comes with 25 yr expected life cycle). P-3 deal was suggested. 2nd hand ~US$100+m per plane (Taiwan bought 12 for US$1.3b). Unlikely to go P-8 due to cost ($2X0+m per plane). In contrast, the new-builds S-70s cost $53.77m a piece (DCS 655 report).