Well here's the deal (as someone who works out of Pavehawks). What you'll find out in the fleet is a mix of aircraft in various stages of upgrades. For example, right now out of our six birds, 3 have the most current ugrades. Plume detectors on the nose and tail fairing (not on the step sponsons), and 6 AN/ALE-39/47 Counter Measure Dispensor Systems. One on each side of the aircraft on the sponsons, and also aimed horizontally outward (adjustable mounts), and 2 on each side of the tailboom, one firing up and one firing down (just like in Gino's pictures). They also have the HF antenna and radio removed (laundry rack on the lower left tailboom). 2 have external ammo bins and gun mounts and there are some other subtle systems upgrades which might show as an antenna moved here and there. Note that the 2 with the external gun mounts/ammo bins have their forward flare/chaff buckets repositioned rearward off the sponson about midway on the main gear strut. This is because the new external gun mounts attach where the buckets used to be on the sponsons.
Now these birds are fresh out of depot (either Texas or Korea) and are coming back in the gray paint schemes.
We also have 3 in the partial upgrade configuration. The main diferences being the plume detectors on each forward sponson (canted outward) and the retention of the HF radio and antenna. Oh...and they're still painted Euro-I. Now bear in mind these particular 3 birds still have the AN/ALE-39/47 CMDS with 6 chaff/flare buckets.
The older system that we went away from a long time ago is the 4 countermeasure bucket configuration that you still see on US Army Helo's, to include MH-60L's. This is the M-130 general purpose dispensor and it was mounted firing downward on each sponson, and 2 on each side of the tailboom I believe firing upwards . It holds less countermeasures than the AN/ALE-39/47 CMDS (which holds 60 flares or chaff bundles). The reason we changed over were obvious...more countermeasures and better defensive coverage. Include that the newer detection system that went with the upgrade made the system better by increasing automation and detection ability.
Understand that whenever there's a new upgrade, we (USAF Rescue Squadrons) don't all just shut down and send all our birds to depot until they're upgraded, rather they're cycled through. That's why you see the mix of birds and there different configurations.
Sincerely,
Your humble Pavehawk answer man.