Northrop Grumman (NG) recently conducted an internal test of an ASW (anti-submarine warfare) configured Fire Scout MQ-8C UAV (actually, a modified Bell 407 simulator of the Fire Scout) in Oct 2020. The test was declared a success (it could have crashed on takeoff and it would have been declared a success – that’s the way these staged tests work) but the real point is that after years of commentator speculation about the benefits of UAV ASW, someone finally made an actual effort, regardless of the real degree of success or failure. Yes, I’m aware of the 2017 MQ-9A sonobuoy tests but that was sonobuoy integration testing, not ASW testing.
Moving on, let’s take a closer look at both the promise and challenges of UAV ASW.
A NG spokesman claimed that the Fire Scout could operate 100 miles from the host ship and with up to 12 hours endurance.(1) Concept art and verbal descriptions depict a Fire Scout with two sonobuoy dispensers holding a total of 40-48 miniature sonobuoys although testing was apparently conducted with a single, smaller, sonobuoy dispenser.
|Artist's Concept of ASW Fire Scout|
Some advantages of an unmanned ASW platform include:
Extended Range/Endurance – The MQ-8C can, under the right conditions, extend the ASW range from the host ship and, again under the right circumstances, the endurance of the ASW effort. The Navy/manufacturer claim 100 miles and 12 hours endurance, however, those are predicated on minimal loads and minimal sonobuoy usage – hence, the ‘right conditions’ and ‘right circumstances’.
If the payload increases (carrying torpedoes, for example), the range and endurance drop dramatically. NAVAIR lists endurance as 12 hours with a 300 lb payload (2) although this is somewhat misleading since transit time has to be accounted for (an hour out and an hour back, for example, at the 115kt cruising speed(2)). Throw in reserve fuel/time and the endurance is further reduced. Add heavier payloads – like a 600 lb Mk 54 torpedo – and endurance will drop drastically. Still, several hours of loiter time is potentially useful and impressive.
Far more importantly, if the sonobuoy usage is heavy, the endurance becomes meaningless. Once the sonobuoys are gone, the helo has little else to do but return to the host ship. Yes, it can hang around and listen for a while but with no active contact, that would be largely pointless. If sonobuoys are dropped in strings of, say, 5, a Fire Scout with 40 sonobuoys would be able to lay only 8 strings. In a combat scenario, where every slight sonar twitch demands investigation, 8 strings would be used very quickly. One might recall that S-3 Vikings, acting in the extended hunting role, tended to deploy sonobuoys in chevrons resulting in heavy sonobuoy expenditure. Assuming a Fire Scout would behave similarly, sonobuoy depletion is an issue. Thus, endurance is probably a misleading and meaningless claim.
There are also some potential challenges to unmanned ASW which include:
Weapons – Currently, there are no plans to put weapons on an ASW Fire Scout. This makes the Fire Scout only partially effective and requires two platforms (a second, weapon carrying platform) to perform the function of a single manned helo or P-8. The lack of weapons also means that the Fire Scout will have to maintain contact until another platform can arrive which is no easy feat.
Communications – Operating at a range out to 100 miles puts the Fire Scout well beyond line of sight communications. It will either have to climb to higher altitude to maintain communications or depend on some kind of satellite communications or other methods which are less likely to be available in combat. This also raises the issue of the communications broadcasting the helo’s location. The communications requirement to transmit the kind of data intensive packages involved in ASW detection and tracking – and from multiple sonobuoys! – is enormous, I would assume (not being a combat communications expert). Add in the requirement that the data be near real time and the comm load is immense and continuous. This just screams out detection of the Fire Scout.
Not to be ignored is the control communications link. UAVs have a disturbing tendency to lose command link and wander off, never to be seen again. There will be a certain degree of attrition attributed to command link loss.
Off-board Processing. The communications discussion leads directly to the issue of off-board data processing. Unlike the old S-3 Viking, SH-60 type helos, or P-8s which have sonar analysts aboard the aircraft, the Fire Scout will, of course, be unmanned and data processing will have to occur aboard the host ship. This causes the communication issue just described and introduces a degree of lag between the Fire Scout and the host ship. Of course, ASW is, generally, a pretty slow affair so this will likely not be a severe problem.
Payload – Fire Scout is a small helo and payload capacity is uncertain but limited. I’ve seen widely varying claims but NAVAIR lists the payload as 700 lbs (2). By comparison, a Mk 54 lightweight torpedo is around 600 lbs. NG demonstrated a very small, very lightweight, 220 lb torpedo drop from a Bell 407 in 2016.(3) Of course, it’s highly questionable whether such a small torpedo would be effective against a submarine given that our largest, Mk48 torpedoes, were deemed to be of questionable lethality against Soviet Union submarines. Smaller diesel subs, less stoutly constructed, might be hindered by such a small torpedo but that, too, is questionable.
We see, then, that unmanned ASW potentially offers benefits for range and endurance but those benefits exist only under certain conditions and are potentially offset by the challenges such as limited payload, communications, lack of weapons, and off-board data processing. The ability to potentially push the ASW outer layer further away from the host ship is useful and, to a limited extent, makes up for some of the capability we lost when the S-3 Viking was retired without replacement.
The major challenge seems to be the lack of weapons which means that any prosecution requires two aircraft to equal a single Seahawk or P-8. The ability of an unmanned aircraft (or any platform, to be fair!) to hold contact on a submarine for an extended period until a weapon carrying platform can show up is highly suspect.
On balance, I’m not seeing sufficient justification for an unmanned ASW Fire Scout to replace a full size Seahawk helo. Now, a very small, UAV carrier with a bunch of Fire Scouts might well be a useful addition to any naval group and this is the developmental direction I’d explore.
(1)USNI News, “Northrop Grumman Pitching Fire Scout Helicopter Drone for ASW Missions”, Sam LaGrone, 16-Feb-2021,
(3)The Drive website, “Northrop Grumman Reveals New Mini Torpedo Aimed At Arming And Defending Navy Submarines”, Joseph Trevithick, 21-May-2020,