What problems would the early F-16 have if they were to fight during night?

Question

From Wikipedia:

Designed as an air superiority day fighter, it evolved into a successful all-weather multirole aircraft.

There is no citation for this, so I suppose first asking if this is even true should be the first order of business. However, my real questions are the following.

1. Assuming the quote above is true, what difficulties would early F-16s (F-16A?) have with night operations when encountering enemy aircraft?

2. What is it with modern F-16s that make them better suited for engaging enemy aircraft during the night? Obviously I know they have more modern avionics, but specifically, what is the difference in this night fighting context?

Answer 1

When the LWF program began, its founders envisioned an aircraft purebred to engage the Soviet threat with machines which more closely matched the majority of Soviet fighters at that time ie lightweight, very maneuverable day fighters ie equipped with minimal avionics, a cannon(s) and short range IR guided missiles. Pierre Sprey had envisioned an even smaller fighter when he didn’t even have a fire control radar in it, but it was not developed past his proposal.

The prototype and development F-16s were a far cry from a modern Block 60+ F-16 is today in terms of avionics and capabilities, but the first service F-16, the Block 15 F-16A/B, had good day and night air-to-air capabilities with the APG-66 radars. They were however limited to good weather air-to-ground operations as they were limited in their precision munitions delivery capability.

Upgrades over the next three decades of service led to the current incarnations of the Viper equipped with helmet mounted cueing systems, advanced fire control AESA radar sets, IR night and precision weapons targeting systems, BVR TARH capable air to air missiles, advanced glass cockpit displays, etc. It must also be noted that, while these system offer addition capabilities, the added weight and complexity diminishes aircraft performance in traditional fighter metrics as well. Nevertheless the F-16 still remains a fine fighter regardless.

The capability vs cost vs performance debate is always controversial and does not show any signs of ending soon, though the military seems to prefer the most advanced and capable hardware it can buy at the expense of operating costs and reliability. This has been made painfully clear with the F-35 program.

Answer 2

The main disadvantages of night operations are that the pilot can't see targets and threats as well, and that the background is cooler, so the aircraft has a more easily detectable infrared signature. This is true of all aircraft, but over time avionics have improved that mitigate the limitations of the pilot's vision. The IR signature is dealt with by trying to kill the enemy from very far away--to be able to see them before they see you. Range of detection systems has increased over time.

Here are some examples from the Wikipedia article:

The MLU introduced compatibility with night-vision goggles (NVG). The Boeing Joint Helmet Mounted Cueing System (JHMCS) is available from Block 40 onwards, for targeting based on where the pilot's head faces, unrestricted by the HUD, using high-off-boresight missiles like the AIM-9X.[88]

...

The F-16A/B was originally equipped with the Westinghouse AN/APG-66 fire-control radar. Its slotted planar array antenna was designed to be compact to fit into the F-16's relatively small nose. In uplook mode, the APG-66 uses a low pulse-repetition frequency (PRF) for medium- and high-altitude target detection in a low-clutter environment, and in look-down/shoot-down employs a medium PRF for heavy clutter environments. It has four operating frequencies within the X band, and provides four air-to-air and seven air-to-ground operating modes for combat, even at night or in bad weather. The Block 15's APG-66(V)2 model added a more powerful signal processing, higher output power, improved reliability and increased range in cluttered or jamming environments. The Mid-Life Update (MLU) program introduced a new model, APG-66(V)2A, which features higher speed and more memory.[89]

...

The Block 40/42's APG-68(V)1 model added full compatibility with Lockheed Martin Low-Altitude Navigation and Targeting Infra-Red for Night (LANTIRN) pods, and a high-PRF pulse-Doppler track mode to provide continuous-wave radar (CW) target illumination for semi-active radar-homing (SARH) missiles like the AIM-7 Sparrow. Block 50/52 F-16s initially used the more reliable APG-68(V)5 which has a programmable signal processor employing Very-High-Speed Integrated Circuit (VHSIC) technology. The Advanced Block 50/52 (or 50+/52+) are equipped with the APG-68(V)9 radar, with a 30% greater air-to-air detection range and a synthetic aperture radar (SAR) mode for high-resolution mapping and target detection-recognition. In August 2004, Northrop Grumman were contracted to upgrade the APG-68 radars of Block 40/42/50/52 aircraft to the (V)10 standard, providing all-weather autonomous detection and targeting for Global Positioning System (GPS)-aided precision weapons, SAR mapping and terrain-following radar (TF) modes, as well as interleaving of all modes.[42]