Hawker 4000 set for major upgrade progra
Owners of Hawker 4000 super-midsize jets will receive compensation in the form of alternative lift while their jets undergo an extensive upgrade and enhancement program beginning early this year. The roughly 40 Hawker 4000s delivered thus far need to receive a fuel system modification to meet FAA Part 25 Amendment 102 standards, and Hawker Beechcraft (HBC) is combining that work with an upgrade and enhancement program to avionics, engines and systems. The FAA allowed the Hawker 4000 to fly under exemptions that expire in 2014, and HBC is taking care of customers’ airplanes well before the deadline. The entire upgrade and enhancement program is expected to be finished next year.

Alternative lift is for the average number of Part 91 hours that owners would normally fly, but not for charter-revenue-generating trips lost as a result of the upgrade. The Hawker 4000 will be the first business jet to achieve Amendment 102 compliance, once the modifications are done. “In almost every case, [owners] are excited about this program,” said Doug Davidson, Hawker 4000 director of product support. “They weren’t expecting [the enhancements] as part of the 102 upgrade. Early adopters are taken care of, and customers will see improved value [for their 4000s].”

“While we have our customers’ airplane in our hands,” said Shawn Vick, HBC executive vice president, “the incremental effort is not that great to give them the benefits and features [of the upgrade and enhancement program]. It is costly for this enterprise, but we know it’s the right thing to do.”

The fuel system modifications require removal of the interior and fuel system wiring harness isolation, installation of a ground-fault interrupter (GFI) in fuel pump wiring, rivet replacement and skin modifications on portions of the wings and addition of Glyptol dielectric paint. Later model 4000s already have most of the fuel system modifications and will need only the GFI installed and hooked up to existing wiring.

The upgrade and enhancement program will take about three months per airplane and work will be done at HBC’s Little Rock, Ark., service center. Some wing paint work may be done at HBC’s San Antonio, Texas, service center. HBC is paying for the entire upgrade and enhancement program except for avionics upgrades that weren’t part of the original purchase agreement.

The upgrade and enhancement program includes the fuel system mods and what HBC describes as a “significant upgrade” to the Honeywell Epic avionics, Fadec software upgrade for the engines, new unattended mode for the APU, new landing-gear control module and other systems upgrades and a higher capacity and improved toilet. Also part of the upgrade program is removal of yellow sheets–compensating procedures or restrictions on some systems–from the aircraft flight manual.

“There were some parts of the airplane that we had to put to sleep when we certified it,” said Doug Davidson, Hawker 4000 director of product support. “The technology was either new to the FAA or we hadn’t fully vetted it, so we’re going to wake up some of that functionality.”

Avionics
An advantage of modern glass cockpits is that upgrades are simpler to install–in many cases just a software change adds greater functionality. But in the case of the Honeywell Primus Epic system in the Hawker 4000, hardware work is also needed. The Block Point Upgrade-A (including Load 20) mod of Primus Epic brings the Hawker 4000 avionics suite up to current standards and adds new features that pilots have been waiting for.

Hardware changes include replacing the Epic system’s primary processor–an Intel Pentium II chip–with a much faster Pentium M, the Intel architecture design that preceded the more recent Core chip design. GPS receivers and a new GPS antenna are also included, as are upgrades to platform software, EGPWS and the communications management function radios. New graphics modules are being added, and wiring harnesses modified to add new functions.

It is on the screens of the FMSes, PFDs and MFDs that pilots will see major benefits of Load 20. Pilots will be able to view electronic charts on both MFDs, use the cursor control device for more system control functions and view graphical weather on the displays.

The FMS will be able to generate takeoff and landing data and it also features go-around transition to lateral navigation, automatic approach preview and GPS backup. Also part of the upgrade are Honeywell’s Runway Awareness Advisory System, electronic checklists, wind-shear alerts and warnings upgrade to the EGPWS, GPS Waas with LPV approach guidance, RNP 0.3/0.1 navigation performance, vertical glidepath GPS approaches and Category II logic added to the ­autopilot and displays.

Engines
The Fadec-controlled Pratt & Whitney Canada PW308A engines are easily updated with a software change that adds climb performance. One-engine-out takeoff thrust is doubled to 10 minutes, which allows more favorable takeoff and climb performance calculations. The software change also improves reliability; caution and advisory system (CAS) messages now flag minor faults as short- (150-hour) and long-term (600-hour) limited dispatch messages; high-altitude ground starting, engine sync and engine fuel monitoring and recording are improved; and “removal of automatic dry spin reduces crew workload in case of aborted engine start,” according to HBC.

Systems
Pilots will appreciate the ability to leave the cockpit with the APU running with the new APU-unattended mode. The APU generator load shed scheme is improved and the APU will be able to power all displays, avionics and pitch trim. The fire and overheat protection system test uses a single test for the entire system, and batteries are used to power smoke detectors. Fault reporting for landing-gear problems is more accurate, thanks to a new Eldec landing-gear control module. The earlier Eldec module was providing erroneous startup indications. Left and right transformer rectifier units now have segregated CAS messages.

Lavatory
For a jet that can fly more than 3,000 nm, the toilet tank was small, and the upgrade program replaces the toilet with a new one that doubles tank capacity to 7.5 from 3.75 gallons. The tank is angled three degrees at the bottom to “facilitate better waste removal,” and depth is larger, too, five inches versus two inches. A traditional steel flapper valve is added to provide tank separation. The new toilet does not take up any extra interior space.

FAA certification regulations are the reason that early Hawker 4000s need to go back to HBC for the upgrade and enhancement program. The regulations are a result of the TWA 800 Boeing 747 explosion over Long Island in 1996 and are designed to help prevent explosions due to fuel system electrical problems.

A key fuel system modification is addition of ground-fault interrupters, basically extremely fast-acting circuit breakers, in the fuel pump wiring circuit. These are mounted on the secondary pressure bulkhead on the baggage compartment side. If an electrical short-circuit occurs in the fuel pump wiring, the interrupters quickly shut off power to the boost pumps.

The latest regulations require that fuel system wiring be routed through dedicated flexible red tubing to protect it from damage. Glyptol dielectric paint will be added underneath the newly protected fuel system wiring where it sits on center section skins, adding yet another layer of protective insulation.

On the first 25 Hawker 4000s, to further improve electrical grounding for lightning protection, an extra layer of glassfiber topped with a thin layer of aluminum will be bonded in place on the outboard four feet of the top and bottom of the wing. In the same lightning-protection vein, some hammered rivets on the inboard section of the wing are being replaced with Hi-Lok threaded fasteners. “The reason is that you can tell when a Hi-Lok is properly installed,” said Nicolas Begley, Hawker 4000 upgrade and enhancement program manager. “And you can put seal caps on them and get this independent and redundant system protection.” The new insulation will be difficult to spot. “Once it’s blended and sanded,” he said, “the only way you’re going to tell [it’s been done] is the wings are repainted. The rivet line you normally would have seen is no longer visible.”

In-house Project
The Hawker 4000s needing the up­­grade and enhancement have been scheduled for specific slots at HBC’s Little Rock facility. HBC did consider doing the work at other factory-owned facilities, Begley explained. “We looked at that, but the reality is that we want to go down the learning curve and improve the cycle time and standardize the process in our own production environment.

“When we give the airplane back to its owner, we’re going to go through the same exact process we do here [for new aircraft deliveries]. We spend over a week in delivery prep. Once the airplane goes through the modifications and everything’s back and reinstalled and cosmetics are addressed as required, it’s going to go through our customer advocate managers. They’re going to inspect the aircraft. We’re going to make sure the customer receives a delivery experience that’s on par with what he should expect to receive as a new delivery.”

“[The process] has been scheduled for the purposes of ensuring quality, consistency and repeatability,” said Vick, “at one location with a team of people who understand this task. We’re going to take the aircraft in based on sequential delivery. The rigor around the process is to ensure that all the customers are treated exactly the same in order of the delivery of the airplanes.”

Customers will be able to follow the progress of their upgrades with a dedicated Web site. After the upgrades are finished, customer pilots will have time to conduct acceptance and familiarization flights.