IAI's upgrade of the F-4 is satisfying its initial customer.
Arie Egozi/TEL AVIV
THE UNOFFICIAL DEBATE in the Israeli air force is whether the upgraded McDonnell Douglas F-4 2000 will still be in service in 2005 or in 2020. This debate stops at the gate of the Israeli F-4 2000 squadron in central Israel. Squadron commander Lt Col "Y" can not hide his affection for the old fighter. "This aircraft has a soul," he says, and everyone in the squadron who has anything to do with the "Kurnas", or sledgehammer, as the F-4 is called in Israeli service, agrees that, even in a modern air force, it can be used to deal some painful blows to the enemy.
The F-4 2000 upgrade programme in Israeli service began in 1980 with a three-year definition phase. The planners had two main goals - to prolong and improve the operational capability of the fighter, and to simplify its maintenance. "Over the years, many minor modifications were performed, creating a maze of wiring that required acrobatic skills when a technician had to access certain parts," says Lt Col "D", head of the Israeli air force's aircraft-structure department.
NEW HARNESSES
When the first F-4 arrived at the special-upgrade hangar at the Israel Aircraft Industries (IAI) main factory, the work order included the replacement of 300 wiring harnesses, the replacement of most of the hydraulic pipes, some structural improvements, mainly in the wings and landing gear, a re-arrangement of the cockpit and the installation of advanced avionics.
The old harnesses were replaced with improved wires and coated with Kepton fireproof insulation. Kepton is less flexible than standard wire insulation, and is unsuitable for the wiring in the landing-gear area. Standard wires have been used there. The new harnesses have been fitted with improved connectors which are less affected by electromagnetic interference. "When the first prototype was ready, we tested the new harnesses to try to locate any cross-interference between all the aircraft's electric switches and antennas. When some interferences were located, we changed the location of some antennas and improved their insulation," says Lt Col "D".
The cockpit applications were the task of a special team of engineers and pilots. The work includes a wide-angle head-up display (HUD) in the front cockpit and multi-functional displays (MFDs) in the rear cockpit, to allow almost full hands-on-throttle-and stick capability. While the upgrade of the prototype continued, US avionics company Norden developed an advanced synthetic-aperture radar to replace the original APQ-120.
Although Israel will not disclose any of the specific capabilities of the new APG-76 radar, Lt Col "Y" is ready to say that the Israeli air force is constantly updating the inertial system, so that "-when we have to release weapons, everything is more calibrated and zeroed. This radar has put us far beyond what we could do with any other system in the past."
The radar is "combat-proven" and, during the recent "Grapes of Wrath" operation by the Israeli defence forces against Iranian-controlled guerillas in southern Lebanon, its capability was proved. "Every bomb was released in the heart of the aircraft's envelope," claims Lt Col "Y". The radar display can be switched to the MFDs and the pilot can also switch the HUD image to one of the MFDs in the navigator's cockpit. "The radar and HUD give the aircraft an air-to-air capability similar to that of a Lockheed Martin F-16," says the squadron commander.
SURGICAL STRIKES
The laser-guided bombs are efficient in Lebanon, where "precision" raids are called for, in an effort to avoid civilians. The bombs, the laser designator and AIM-9L air-to-air missile constitute negligible cargo for the F-4.
When the upgrade was planned, IAI offered to re-engine the F-4 by replacing the Pratt & Whitney J79 engine with the P&W 1120, then developed for the now-defunct Israeli Lavi fighter. One of the F-4 2000 prototypes was equipped first with one PW1120, and then with two, but budget problems killed the re-engineing idea. The pilots do not seem to regret this decision, despite the better thrust of the PW1120. "The J79 is a reliable engine and does the job," says technical officer, Major "M".
The upgrade includes the installation of a video tape recorder in the cockpit, connected to the HUD and MFD, and recording them constantly. "This system improved my capability as an F-4 pilot by no less than 15%. It is a good debriefing tool and it proves itself after every mission," says the squadron commander.
Half of Israel's 90 original F-4Es have been replaced or modified. The added value, say the planners and operators, is far beyond originally envisioned and this, they believe, means that the F-4 2000 will be flying for years to come.
Source: Flight International
