A recent article in Netwerk24 asserted that Angola’s recent purchase of Su-30Ks poses a serious threat to South Africa’s security and air power capabilities. Although this may bear some thought and consideration, a counter-argument in response is detailed below.
In short, modern air combat is no longer merely about raw performance, it’s about the interaction of complex systems of systems, all of which have a part to play. Fighter pilots are now concerned not only with dogfighting, basic radars and short-range missiles, but with juggling a complex array of jammers & other EW systems, tactical data links, covert and active radar modes and missiles which are massively more advanced than just a few years ago.
One interesting look at how those systems can interact to allow even flawed aircraft like the F-35 to prevail is highlighted in this fascinating simulation of the F-35’s theoretical capabilities in BVR air combat from the Royal Aeronautical Society’s Tim Robinson.
If we look at the SAAF’s situation, there are some clear gaps that need to be filled:
1) A lack of a proper AEW aircraft
2) A lack of aerial refuelling platforms
3) A lack of an operational beyond-visual range (BVR) missile
The first can be mitigated somewhat by the use of a single Gripen in the AEW role feeding radar data to the attacking Gripens which operate in EMCON nose-cold mode, with all active transmitting sensors turned off. The Gripen has an impressively small RCS, making it difficult to detect unless the Su-30Ks are burning the sky with their radars on full power, which would make them vulnerable to being detected from far out by the Gripen EW systems.
The second is a problem, mitigated slightly by the way the Gripen is designed to be easy to sustain and operate away from main bases, but it’s a gap that ideally needs to be filled. Without it the Gripen has an 800 km – 900 km combat radius with 30+ minutes on station, adequate for most defensive scenarios but there’d be a lot more flexibility in mission scenarios if that could be extended by aerial refuelling.
Finally, the lack of a BVR missile is temporary and can be rectified quickly if the need were there by acquiring MBDA Meteors and giving the SAAF pilots needed refresher training. As it is, I would expect a BVR missile buy within the next five years, as it is on the Gripen roadmap as a necessary capability.
Finally, there’s doctrine. For various reasons, the Angolans allowed their air force to lose much of the expertise it gained in the 1980s and with it their ability to keep up with the latest developments in air power doctrine and technique. The SAAF, on the other hand, has the Air Power Development Centre and still places as much emphasis on up-to-date techniques and training as funding allows. This was highlighted by the excellent performance of 2 Squadron’s pilots in within visual range combat in Ex Lion Effort, where they also learnt valuable lessons in effective BVR combat.
Finally, beginning from next year the Gripens will be armed with the A-Darter, an extremely capable short-range air-to-air missile which is better than the R-73s the Angolan Su-30s are going to be equipped with. It’s nearly smokeless, very difficult to jam or decoy and has a range of at least 20km with good terminal manoeuvrability. In the interim they carry the equally-impressive IRIS-T, procured as a stop-gap until the A-Darter entered production.
So, let’s walk through a possible scenario in which four SAAF Gripens have to come up against four Angolan Su-30Ks for some reason. Let’s assume equal starting altitudes, a hostile situation allowing a first-shoot ROE and equivalent closing distance. We’ll also assume no ground radars, though those would play a factor in a real situation.
The first thing the SAAF would do is send a single Gripen D up near its service ceiling behind the lines, with its radar on full power and the picture being data-linked to the four Gripen Cs in the advance flight. The SAAF Gripens might fly in a wide formation of two each, providing good separation for their EW sensors and the ability to initiate a pincer movement if necessary. The SAAF pilots will constantly adjust positioning to ensure that they’re not outpacing the Gripen D in the AEW role and moving outside its protective radar umbrella.
Angola’s Su-30Ks carry the relatively old NIIP N001 Myech radar, which features an older conventional mechanically-steered cassegrain antenna and few of the electronic niceties that came in later variants. As a result of its age and widespread use, the radar has been quite well-studied and its capabilities are known. For one, it can detect a 1 m² – 3 m² target at between 80 km – 100 km depending on flight profile and when at full power. The Gripen C has a frontal ideal RCS of 0.1 m², going higher depending on angle, so let’s call it 0.5 m² to be fair and to account for marketing exaggerations. Simplifying things a lot, that would drop the Su-30K detection range down to 40 km – 50 km at best and the tracking range down to somewhere around 15 km – 20 km.
Note too that the Swedes have been developing and customising the Gripen’s systems to handle new-generation Sukhois and MiGs from the start, as a result of which there is serious capability in the onboard EW systems and radar.
The Gripen’s PS-05/A, on the other hand, which in this scenario is up at 50 000ft, is said to be able to acquire a Su-30K-sized aircraft at 120km and track it for a firing solution not much later. And the moment the Su-30Ks appear on that radar, the information is immediately sent to the four Gripen Cs flying ahead allowing them to use it to launch Meteor or Marlin missiles. As they’d be about 60 km away from the Flankers and out of detection range and don’t turn on their radars the entire time they won’t be seen until missile release.
In other words, given current capabilities plus the acquisition of a BVR missile, the Su-30K pilots would get missile launch warnings before they could see a single one of the launch aircraft. They’d be able to detect the Gripen D in the AEW role, but it would be too far away to do anything about and the Meteor has a good probability of kill for a long-range missile. Splash four Flankers.
This is without the PS-05/A Mk4 and Mk5 upgrades, which double detection and acquisition range. It also ignores the use of the Gripen EW system to jam the N001, which it’s quite effective at as the N001 does not have spectacular peak transmitting power.
Of course, this is a contrived scenario and it elides a lot of the complexities and variables, but it’s nonetheless as accurate a look at the relative capabilities of the SAAF’s new-generation Gripens vs Angola’s old-generation Su-30Ks as we can make with open source data. Were we speaking about latest-generation Su-30s with AESA radars and better defensive subsystems the picture would change drastically, but we’re not.
The Su-30K also has performance advantages over the Gripen in a close-in dogfight, but those too are mitigated by the Gripen’s carriage of the IRIS-T or A-Darter high off-boresight missiles and Cobra HMDS which allow pilots to fire missiles at targets in any direction, including directly behind their aircraft.
In sum, this acquisition is not the threat it initially appears to be. Nor do the Angolans intend it to be that, as they seem to want to use their Su-30Ks the same way they’ve used their Su-27s, for their ability to cover vast distances and mount long-range airstrikes in Angola. No doubt they find this discussion bemusing.
Thanks Darren – very insightful!
Quiet interesting analysis Darren.
– I still think the SAAF should consider acquiring several modern Su-30s just to allay whatever concerns or threats that might arise in the future’ to assist the Gripens.
– Lastly, Eskom’s power stations are also too exposed, I think some Nuclear Powered Stations should be build underground (inside old mines)’ just for strategic purposes. In the event of War these are targeted & having spent 10s of billions of dollars it would b a setback if bombed by enemy aircraft.
Why would we buy Su-30’s? Rather buy additional Gripen…it’s a better aircraft..as per the analysis above. Su-30 is old tech now….especially the Angolan ones.
Once we get BVR and A2A refuelling – solid!
I agree with this, should the need arise to enhance the SAAF’s fighter capability the first option would probably be to acquire Gripen E/Fs to augment or replace our Gripen C/Ds.
Of course, any actual decision would depend on both what threat would arise and what sort of funding would become available, but for the near future the SAAF’s fighter capability is adequate assuming a BVR missile is acquired.
Aerial refuelling and AEW aircraft are a must-have, but not super-urgent and can wait a few years.
Once GBADS and the SAAF’s Project Chutney are complete the country’s early warning air defence network will be a lot better as well and, again, should be good enough for our defensive posture and needs.
Thanks Darren, agreed 100%.
ohh i meant the latest generation of Suykhoi fighter jets, the Sukhoi T-50 Fighters, which would ensure the SAAF becomes capable of serious defence or counterattack in the event of a formidable Airforce Attack. Gripens alone clearly are not enough’ judging by the information above.
Because we would be unable to afford the cost of acquiring or operating them.
It’s the same reason we didn’t buy Rafales, Typhoons or F-15s, even though the SAAF initially wanted aircraft in that class.
The Gripens are superior to anything else in the region for now and will ensure South Africa air superiority for the near-term future. Only if that situation changes would it become necessary to look at other options.
I was under the impression that the T-50s are aimed at a market like ours & thus more affordable than the Rafales?
I stand corrected, but its estimated they wld retail for around USD$90mil a piece, which isn’t far off from the purchase price of the Gripens?
– I do agree however, we need A2A refuelling and the BVR missiles though.
The actual fly away unit cost of our Gripens, minus the other contract add-ons, was closer to $30 m. As a general rule of thumb the total contract cost of a fighter purchase is at least double the combined fly-away unit costs.
The T-50 will also be far more expensive to operate than the Gripen, both because it has twin engines and because the Russians don’t focus on reducing maintenance cost in the same way Saab did with the Gripen. That’s just a factor of different priorities, the same reason the U.S. was willing to tolerate the F-14’s gargantuan operating cost for so long.
Most of the above assertions are speculative.
1, How do you judge the skills of Angolan pilots, did you follow them to Russia to see their training and do you work for their air force to know how many hours and types of maneuvers they fly at home?
2. SAAF Gripen pilots fly far far below standard hours, and have not been see in combat maneuvers since after 2012 Lion Effort. Technically, no SAAF Gripen pilot is combat qualified due to low hours per year.
3. SAAF claims of spectacular performance in Lion effort 2012 were not confirmed by anybody else in the exercise, it was never proved and was a claim by SAAF pilots who went to Lion Effort.
Sources in Europe say the other countries too were making similar claims of shooting down SAAF Gripens in Lion Effort.
So who do we believe, the SAAF or the Hungarian and Czech pilots also claiming victory in the same war game ?
4. RCS of Gripen is speculative, it’s not a number from SAAB.
5. Gripen jet is not a stealth fighter, enemy radars will detect it even if the Gripen switches off it’s own radar.
6. Angolan Su-30 K is being upgraded, unless their military reveals, you never know the type and range of radar they have chosen for the upgrade, it may be classified.
7. A-Darter missile range is bad at 19 km maximum, it’s 19 not 20.
8. Angola may be getting BVR missiles, we don’t know yet.
9. Angola is a friend of South Africa today, we do not expect a war, but with Ukraine and Russia former blood brothers/soul-mates now at ‘war’……always expect the unexpected.
10. Angola has the range to strike deep inside South Africa if they need to, and South Africa cannot retaliate due to range limitations.
I think your point 1 is justified of course. Most would assume SA pilots to be better but it’s just an assumption.
I think the assumption is based on the idea that western training is superior which is not true if one looks at tactics used by eastern trained pilots in skirmishes between India vs. Pakistan, US vs. Vietnam, Greece vs. Turkey etc.
I think previously this was justified pre-94 because training and funding was available during the border war era. But since 1989 we’ve been nose diving.
I don’t think our training is superior but I do think we train more than most Southern African countries.
If one takes the average infantry soldier in South Africa and compares to a average infantry soldier is say Angola. One would have to look at training regime and also the success factor. I think it’s common knowledge that the bad apples are allowed to go through in the SANDF even if they fail and until that stops I don’t think the SANDF will shake off it’s negative perceptions.
Thanks for this response augustine, you make a number of fair points which I think are worth addressing.
1. It was not my intention to claim that the Angolan pilots were unskilled, only that they have not been given the necessary support of their government in staying up-to-date with the latest techniques and doctrine. This is a pity, because I know for a fact that the country has some fantastically-skilled pilots who are being harmed by short-sighted government policy.
For what it’s worth, the same is in danger of happening to the South African Air Force, where a critical lack of funding has meant that certain skills have withered. It’s a reflection on political leadership, not on the aircrew.
Also note that I intentionally focused primarily on technical aspects of the aircraft and their systems and on doctrine, because I don’t believe Angolan pilots to be inherently inferior.
2. This is incorrect, for reasons I can’t really reveal openly. The entire reason the SAAF maintains a smaller core set of pilots at 2 Squadron but keeps a larger group of current Gripen pilots working as instructors etc is to keep that core group combat qualified. Their hours are sufficient.
3. I have independent confirmation of the results in Lion Effort, but I specifically referred to the WVR results. As with all such exercises there were multiple scenarios tested and the SAAF pilots were thoroughly outclassed in BVR combat, causing a rethink in BVR training, tactics and doctrine. That’s the value of attending an exercise like that, to find the gaps in your own training and correct them.
4. The Gripen’s low RCS has been confirmed in a number of exercises and tests, but as I said the lowest figure is an ideal one based on a specific aspect. It is not all-aspect stealth, nor is it nearly as low-observable as an aircraft like the F-35 or F-22, but it benefits from being a newer airframe with a huge amount of RCS-reduction research done by Saab.
5. Correct, which is why my scenario envisioned the lead Gripen flight flying with passive sensors only, being fed a radar picture by a fifth Gripen acting in an AEW role. Nor is the Gripen radar an AESA model with low-probability of intercept, so that fifth Gripen will be easily visible to the Su-30K sensors as I said in the article.
6. This is true, but based on the statements of Rosoboronexport, representatives of the 558th Aviation Repair Plant and the contract price the upgrades do not appear to be significant enough to include radar replacements. There’s a practical limit in how much you can do with those airframes before it becomes prohibitively expensive and acquiring new Su-30s becomes the better option.
It comes down to what Angola’s priorities are.
7. Whether 19 or 20km, that’s pretty good range for an IR-guided SRAAM.
8. I implicitly assumed a BVR capability for the Angolan Su-30Ks.
9. Well, the original article to which I responded was itself unnecessarily speculative in my view, hence my rebuttal based on the technical aspects. I don’t believe Angola or South Africa are opposing powers and I really hope it stays this way. Angola’s new willingness to participate in regional peacekeeping is fantastic in my view.
I’d also hope to see more exchanges of personnel between both armed forces.
10. This is not the case, South Africa’s air defence radar network remains sufficient to provide early warning over its border area and the Gripens have the range to respond as necessary. Angola does not have sufficient aircraft or resources to mount such a long-range attack with any level of effectiveness.
In sum, I think the most important thing to consider here is that this isn’t meant to be a pissing contest. Angola’s strategic imperatives in acquiring Su-30Ks are the same that drove its acquisition of Su-27s and are based on internal and defensive needs, not offensive air domination needs. They have no intention of intimidating South Africa with this purchase, the same way that South Africa had no intention of intimidating Angola with its Gripen purchase.
This sort of speculation is always interesting and often useful, but we should not lose sight of the bigger picture. Angola and South Africa are not enemies.
Darren, I find your response similar in principle to your original essay, it’s still all your personal speculative assumptions as I cannot find any reliable technical source to confirm almost everything you claim.
1. There is no proof that Angola has no money, oil and gas money, to buy a better radar, and there is no proof that the radar on the Su-30K is still the same radar after upgrade. There are many radar options for an Su-30 wih range from 100 km to 400 km. Can you please prove with a source beyond dispute, the exact radar model that Angola has after the upgrade ?
2. I have contrary reports from Czechs and Hungarian Gripen pilots who claimed to have severally shot down SAAF Gripens in Lion Effort, can you prove me wrong or prove yourself right with a valid source that can be presented in an international forum?
3. RCS numbers on internet for many jet fighters are mere speculations, you have any proof from SAAB for the Gripen?
4. A-Darter 19 km is a bad range for a missile when the Gripen is up against a super maneuverable deadly dog fighter Su-30 Flanker in close range combat where missile can hit target in 15 seconds.
5. Angolan Su-30 has combat range of about 3,000 km and South Africa is about 2,500 km away for a round trip, so how come you say 12 Su-30 jets cannot do much damage to South Africa when jets do random combat sorties? Basic maths and geography maps proves your claim to be very strange.
6. Switch off all the radar you want on the Gripen, and it will be easily detected by an Angolan Su-30, since when did radar waves start failing to detect jet fighters that are not stealth? I need proof that law of physics has now changed and a metal Gripen jet as big as a trailer/truck will not reflect radar waves.
Enemy radar detects you because you have a metal piece of object in the air, not because you have your own radar on.
7. RCS could be small, but does not save you from radar detection, good jets will detect enemy aircraft and also detect it’s missile after launch, the RCS of a tiny missile is being detected and you get a missile approach warning, then somebody wants to tell the world that a huge jet fighter will not be detected because it has some kind of RCS….when it is not stealth? Even a stealth jet with a little bomb bay opening to discharge ordnance will get detected by good radar, USAF F-117 Nighthawk stealth jet was detected by an old Serbian radar and shot down in Bosnia war.
When one writes assumptions, he should let readers know he is speculating and writing personal opinions. Where I work, the standards are very high about claims, facts, or information. Thank you very much.
Long live SADC, unity + peace = progress
Augustine are you truly a military researcher as you claim? I really do not think so. The kind of English you use and the level of knowledge you showcase, is not in line with that of a truly American military researcher. Well, let me help you with your questions.
1. Darren has never made claims whatsoever that Angola lacks funds. He only commented that the government was doing to little to ensure that the skills of their pilots were sharpened perfectly well. In the case of South Africa it was different though since they have Air power development center despite the financial challenges.
About the upgrading the radar-well that will not be advisable at all and will unnecessarily raise the cost. It will be much better to buy SU-30s instead. That’s why we are of the opinion that it will never happen.
2. It appears you are as well not sure how the Lion Effort fare. SAAF pilots fared very well and ahowcased a tremendous skills as compared to their counterpart. However, their challenge seemed to have been on the BVR capabilities.
3. To confirm RCS of gripen, I will suggest you visit manufacturers website SAAB.
4. Combat radius of 3000km to a country that is 2500km will still not work. It has to be 3000km to and from the grounding base or refueling stations. I guess by the time the Angolan SU-30s reach South Africa without airial refueling their pilots will not be there to tell the story. Anyway, no pilot on his right mind would ever take such risks.
5.RCS is what we use to determine how well fighters would be detected by enemy’s radar. If you were truly a researcher like you claim you should have known that. The radar on SU-30K (NIIP NOO1)is so bad that it can only detect targets with an RCS of 1sqm-3sqm. Hence, the low RCS on gripen will be an advantage over SU-30K not to be detected as early as the enermy pilot would have wished for. However some of the latest model are said to have AESA radars.
6. I guess no:5 covers that as well.
7.Darren had never made claims that low RCS will avoid detection at all cost. He merely said that it will halve the possibility of being detected, thus giving an advantage to lauch an attack first.
Dude, you are a bad researcher.
Sello Puo my brother, your national pride as a South African will not shoot down Angolan Su-30 jet, please go buy SAAF a Rafale or Typhoon.
Meanwhile, you say my research is bad because it hurts your national ego and pride, go to defenceweb and see where your South African military experts have said SAAF Gripens must remain parked on ground when Angolan Su-30 fly in anger….Source is Helmod Heitman of Janes Defense magazine and a citizen of South Africa.
Go tell Helmod and Janes defence that are bad researchers.
Damn!! I really cannot believe the amount of stupidity that this fellow man, so called American military researcher is exhibitingexhibiting here. This is not about competition at all. Angola just don’t have the resources to project power to a country like South Africa. I just don’t care what Heitman says because the person who will be doing the fighting is me and the cheetahs. It is not Heitman who will be giving the orders. All this while we were busy talking SU-30K which we know for sure is not as cute and intelligent as SU-30S. You on the other hand you are discussing SU-30 randomly like a mad man. Please attach a suffix on the code to make your work look professional. You are confusing us with this random SU-30, be specific and tell us which one are you talking about. I really undermine your work before I could even go and read any of your articles. The corporate that employed you must have been very desperate indeed.
Moreover, I stand to correct you about A-Darter. With the SRAAMS the range does not matter that much since dogfighting happen within 20km and below and they are mostly effective within that range. Any researcher should have known that. The A-Darter is the fifth generation AAM and like IRIS-T does not really need to be fired only at specific directions. At any direction, the pilot stand a good chance to take out the target even when the target is at the back.
Other than that I believe that you are nothing but a spy. A learner for that matter.
Don’t know if it’s even worth responding to such weak arguments and as this analysis points out, it’s a comparison that shouldn’t have been made in the first place (Heitmann is often referenced in articles by sections of the press critical of current government).
1) Angola is not going to attack SA
2) 12 strike aircraft is not going to win a war
3) Air defense consists of much more than interceptors/fighters
As for the comparison of Su-30 with Gripen.
1) This is the oldest most basic Su-30 (essentially a Su-27). There is no phased-array radar or thrust vectoring. These particular aircraft have been returned by India (evaluated while waiting for M models). As a side note do some research on Indian’s dissatisfaction at engine reliability of this model and repair turn-around time (so of your 12 attackers perhaps only 4-6 will be operational).
2) Su-30 is 3x times larger and heavier than Gripen and latter was designed later and with more information regarding RCS including less “reflective” composite materials. This is why most sources quote the Flankers RCS as 10sqm (some up to 20sqm) and the Gripen at 0.1sqm. That is 100x times less visible!!!!
Here is comprehensive technical comparison between Gripen and Su-30MKK/MK2 (FAR more advanced than Angolan Su-30K) concluding that Gripen as the advantage even jokingly calling it the “Flanker killer”. Just google “The Flanker-G Killer”
All of this is still irrelevant. Angola got more of the cheap long range strike fighters they wanted and could afford and SA got the light cost effective fighter they wanted. Apples and oranges.
Darren, I believe that man called Augustine has pretty little information to do with fighters. Somehow, I think the language is too big for him to consume. In your briefing you have never in any way ever claimed that the gripen fighter is stealth but instead you indicated that it has a low RCS. The SU-30K has the ability to detect target with the dimensions ranging from 1sq.meter to 3sq.meter at 80-100km away and hence the gripen has a frontal ideal RCS of 0.1sq.m; and for the purpose of marketing exaggerations you did fixed it to 0.5sq.m. That is enough to convince me that the gripen stand a greater chance of penetrating SU-30K undetected for about some distance. The aforementioned feature will indeed be good for BVR capability indeed.
Sello Puo, I am Augustine, a military researcher based in North America, I work in defence industry, and in my office are veteran USAF and USMC fighter pilots whom I engage in discussions from live combat, not internet blogs and commentaries.
I ask anyone who has basic university education and knows the difference between facts and assumption to please kindly tell us the source, verifiable and infallible technical source of the information about Gripen jets RCS at .0.1 or 0.5
Did you see what Darren wrote? He said and I quote “The Gripen C has a frontal ideal RCS of 0.1 m², going higher depending on angle, so let’s call it 0.5 m² to be fair and to account for marketing exaggerations”.
He has already said the RCS 0.1 is an assumption by some people likely exaggerated, so his own assumption is 0.5, now how do we prove who is right? What is the real figure is 0.9 ?
I went to university and I am educated enough not to use assumptions as facts, they are speculations. If you write international standard project papers and you quote assumptions as facts, you lose your job or reputation…. or both.
Who do you do your research for?
Anon, you have a project for me? I am open to offers.
Gunna need to see your CV first!
Yes, I’d like to buy property in Nigeria.
How would one do that?
Would you require an estate agent or are there other means?
I might not be a researcher in military but your analysis appears to be flawed to a greater extent. I am currently in the military and have attended quite a number of courses locally and abroad.
The gripen fighter is marketed by manufacturers as having an RCS of 0.1sq.m and Darren only open it up to 0.5sq.m for if there was any exaggeration whatsoever due to marketing.
I applaud Darren for his job well done and I therefore have confidence that gripen can defeat SU-30K in every way.
Dear Sello Puo, kindly post technical data to prove my claims wrong. You being in the military does not make you a source for the world to believe. You could be an admin staff or music band instrumentalist in the military, so you know nothing about jet combat.
SAAB website does not say Gripen RCS is 0.1 so can you quote the sentences from the website and also the web link to prove your claim?
I am sure you will run away from the above question and refuse to prove your claim….your false claim.
Thanks brother.
You are the one whom has come here and said that Darren and other commentators are wrong
But you have provided no data!
Sir, I believe you to be a troll.
anon, I am the perhaps the only one providing verifiable data here, most people are posting assumptions from their bedroom.
I said A-Darter range is 19km. Angola to SA is approx 2,500 km, I have given some other data too and nobody has been bold enough to dispute my data.
Now you prove your own data of Gripen RCS at 0.1 m2……this forum needs a proof from an infallible source…..until you prove it, all your comments on this topic end up in a dustbin. Thank you sir.
I think one has to couple it with South Africa’s doctrine which is defensive in Nature.
Our current doctrine is not to be aggressive thus why we have not obtained a longer range anti ship missile as well as why we have not adopted a land attack cruise missile. If this was not the case the SA Government and Kentron would not have cancelled the MUPSOW and TORGOS projects as well as the Armed Seeker 400 and Bateleur Projects.
As long as Project Chutney get’s implemented and the GBADS project recieves a medium range capability in the envisioned Denel Marlin BVR Project South Africa’s air defence network will be capable of handling anything in the region.
heres a comprehensive article by african military blog on the topic…. a great read.
http://www.africanmilitaryblog.com/2017/10/analysis-south-african-air-force-gripen.html