It is the high-frequency shortwave antenna of a 707-321B, specifically Clipper Yankee Ranger N418PA. Also present on the KC-135.
You can read about the Antenna Coupler Program from the people involved in its development.
You might want to look at What radio frequency bands are associated with the long wire antennas, why do some aircraft have them and ...
This is the In flight refueling probe, which can be used for refueling while the helicopter is airborne:
(image source: pinterest.com)
It is almost 9 meters long to make sure the rotors do not hit the refueling drogue. You can see it in action in the following picture:
(image source: chinook-helicopter.com)
That's one of the two ice detectors manufactured by Collins. Below is not precisely the model used by A220, but serves to illustrate the general layout of the unit:
Image ref: Collins
From this Collins fact sheet, ice detectors
use a magnetostrictive technology to drive the sensing probe to resonate at its natural frequency. As ice accretes on the ...