Just watching the film about the Dambusters raid, it got me thinking. Why did they have to fly so low?
I don’t mean at the target, of course. Why fly low all the way there and back (wiki says 100ft)? The answer seems to be to avoid radar, but why was this so important on this raid and not on regular bombing missions? They lost a total of 6 planes on the way there and back, flying low seems to have been a contributor to this. Why not fly in/out at 30-40,000 feet, surely much less chance of being shot down (and no chance of hitting pylons which cost 2 Lancasters).
Since the raid needed to go in at below 100’ altitude, it’s possible that it might have been infeasible to bleed off the altitude without meeting interference on the way down, and it would have been out of the question to climb back to height after the raid. A fully loaded Lanc’s service ceiling was only a little over 20,000 feet, and it climbed at only 720’ per minute (quicker with less of a load on board, obviously).
WAG : they were flying into the heart of Germany with no fighter escort. Showing up on radar could have meant flying into a hornet’s nest of forewarned German planes with an altitude and situational advantage.
Since the raid was fairly small (19 planes total); the Lancaster was not exactly a combat beast to begin with; the ones used in the raid had specifically been stripped down even more to increase their range & carry weight (including shedding most of the armour and the upper middle gun turret, a.k.a. the Really Important One); and the bombs used were exceptionally heavy and cumbersome (so much so that they wouldn’t fit entirely inside the planes) that could have been a Problem.
Flying low also reduces the time a given AAA gun can shoot at you since they can’t traverse very fast and you’re within their firing arc for less time (you also get more easily obscured by trees, buildings and the like).
So why not *always *fly in at treetop level ? Well, fuel efficiency is much better at high altitude; airman survivability as well since they both can parachute safely and in the event of catastrophic damage can glide farther and/or have more time to recuperate before they hit the ground; large bomber groups flying high can mutually defend against enemy fighter squadrons better; bomb dispersion is wider which statistically improves the chances both that one of them is going to hit *something *worth blowing up and the total damage done to the population & infrastructure; and you can’t hit pylons at 30.000 feet
FlaK and CFIT (Controlled Fight Into Terrain) look like they’re both considerably higher for low-level raids. Of the aircraft that made the flight all of the way to the target five were shot down by FlaK and three were destroyed by CFIT. Now granted that the sample was kind of small (19 aircraft) it still looks like flying low allows hits by FlaK to be more likely than at high altitude. This is because it brings small caliber guns into the mix, I think. High altitude missions can only reached by 88mm and larger caliber guns. Low altitude flights can be reached by any FlaK gun around, specifically 20mm and 37mm guns. That would triple the number of guns firing at you.
Needless to say CFIT doesn’t happen at high altitudes.
All that and it’s damn hard to fly 100 feet off the deck at night. The pilot in the dam busters program was off by 50 feet in daylight. Also If it became a strategy then they would use balloons with cables and nets against them.
I hope I don’t get in trouble for quoting too much, but it is worth reading.
After that raid, 617 Squadron became a sort of specialist unit. It was they who carried out three raids in modified (less armour and weaponry - more engine and fuel), flying 2250 miles (a record at the time I think) to Yagodnik near Archangel in Russia, and then to bomb the Tirpitz with another Barnes-Wallis bomb (12,000lb ‘Tallboy’) and return to Scotland.
Would a raid like this be even vaguely feasible today? I realise it’s almost certainly not necessary to do this because of guided bombs and cruise missiles, but I’m interested in the feasibility of flying current fighters in below radar coverage in a country like Afghanistan or elsewhere, and getting in and out virtually undetected.
“Upon reaching Iraqi airspace the squadron split up, with two of the F-15s forming close escort to the F-16 squadron, and the remaining F-15s dispersing into Iraqi airspace as a diversion and ready back-up. The attack squadron descended to 30 m over the Iraqi desert, attempting to fly under the radar of the Iraqi defences”
Don’t know if it’s required that they be virtually undetected. Surely after bombing the target, the enemy will suspect someone was there. On the way out, you don’t need to go undetected, you just need to get out of there fast/un a way that’s difficult to track and intercept.
Isn’t that basically what happened according to the official story of the bin Laden raid? A group of aircraft (helicopters in this case) flew beneath radar for most of the width of Pakistan, conducted a raid, and returned home. The only detection, so far as is publicly known, was due to the noise of the helicopters flying in the target area (and crashing one of them in the target compound.)
Very low level attack, as was performed, e.g, during Desert Storm by RAF Tornadoes, is deprecated nowadays, as that puts the aircraft in the heart of the threat envelope of anti-aircraft artillery and small arms fire. Not to mention being really difficult to do without crashing. Flying higher (10-20,000 feet and up) does allow for the aircraft to be detected and targeted at a longer range by ground-based radar, but most of the first airstrikes of a modern air campaign are devoted to killing most or all of those radars. Further, if the aircraft is stealthy/low-observable, then even if the aircraft is in line of sight to a particular signal receiver, it may not re-emit enough signal to be visible by that receiver at a given distance or greater. Then, the stealthy aircraft can fly at whatever altitude minimizes the chances of visual or audio detection, and catching a “golden BB”, so long as it stays that far away from any radar.
But facing a state of the art integrated air defense system, featuring powerful, sophisticated radars like those in the MIM-104F Patriot, or the Russian S-400, where it may not be possible to immediate kill all of the radars, then sure, low level attack may come back into vogue. Whether by an aircraft flying all the way to the ultimate target, or to a launch point where the bomb/missile itself flies low level to the target. Utilizing rocket-propelled hard-target-penetrating guided bombs like the BLU-116, GBU-28, and whatever’s succeeded it (it’s been nearly 25 years since Desert Storm, after all): an aircraft can strike a particular spot on the dam with a bomb designed to penetrate 30+ feet into reinforced concrete before exploding with 630 pounds or more of high explosive. It’d make a big hole. And if one isn’t enough, wait a minute or two and smack it again in the same spot with another one. Give the bomb fold out wings and a motor, and the aircraft can release the bomb well away from the target (100 miles or so for the HOPE munition linked above.)
Oh yes. It’s even much easier thanks to better instruments; on-board radar, IR and nightvision and so on. I know for a fact (because I used to work in a company that designed part of it) that the French Rafale has an autopilot toggle that can fly the plane that low, hug the terrain all by itself and zoom about at 450 knots, 90 feet up while the pilot lazily jerks off.
To clarify, the software was not designed *specifically *to allow Rafale pilots to jerk off. The devs just assumed that’s something they’d do :).
Come to think about it, Tomahawk and Harpoon missiles probably have the same kind of software onboard.
I suppose it’s harder to functionally fly below radar coverage in very flat countries that are devoid of any tall vegetation, where the curvature of the Earth is the only limitation on a radio beam. Iraq comes to mind, which would explain why Iraqi radars were very aggressively targeted in the first hours of Desert Storm. Same for naval operations. But Afghanistan ? That place is nothing but peaks and valleys.
Another thing is that unlike most of the night-time bombing missions during the war, the dambuster ones were precision strikes. Most of the time, the night raids were targeting whole cities and so as long as they were in the general ballpark (give or take a few miles) it was fine. Plus after the first incendiaries fell, the target became obvious enough.
With the technology of the time, they needed to be able to see landmarks in order to get in close enough to their targets which they wouldn’t have been able to do at very high altitude. Flying at a few thousand feet would have worked, but would have left them very vulnerable to flak and scrambled fighters. So flying at treetop level was the only solution.
That they do, the Harpoon and similar sea-skimming anti-ship missiles such as the Exocet fly even lower than that at ~15 feet or so off the wave tops. The Tomahawks used in Desert Storm used TERCOM, Terrain Contour Matching which used a contour map of the missiles flight plan that it compared with a radar altimeter while in flight allowing it to fly very low and hit fixed targets with extreme accuracy. After Desert Storm they started using GPS and Digital Scene Matching Area Correlation.
Indeed, the poor Tornado took a beating during Desert Storm compared to other aircraft. It is a very good aircraft, but it was designed for and the RAF crews trained for fighting WWIII in Europe if the Cold War went hot where the SAMs would have been as thick as trees in a forest and one of their primary initial roles would have been all weather very low level attacks on Warsaw Pact runways using the JP233.
Others have commented on the state of play today. Generally, against any developing country’s air defence system, the idea is you are safer at medium/high altitude once the cruise missiles and stealth bombers have degraded the system’s capability. As **Dissonance **has pointed out this was not the case during the Cold War. From the early '60s Warsaw Treaty Organisation missile defences were just too thick on the ground to be knocked out at the outset prior to the bomber force attacking.
The result was that mission profile of the British V bomber (nuclear) force was changed from high altitude to very low altitude attack. Initially the Victors, Valiants, and Vulcans were intended to fly too high and too fast for Soviet fighters to intercept but it soon became obvious they would be vulnerable to the first generation Soviet AA missiles - especially as they were expected to penetrate Soviet air space well ahead of the USAF B52s. The answer was exactly the same as that developed for the Dam Busters raid - go in low, below the operational level of the main air defences, only flying a hell of a lot faster! The Vulcans in particular turned out good at this being both manoeuvrable and robust. Definitely not a comfortable ride though.
