With more than 150,000 built, nothing could be a more familiar sight at the local airport than the high-wing Cessna piston single. So it is hardly surprising that the company stuck with what it knew when it resumed single-engined piston deliveries in 1997.

Since then, Cessna has produced more than 4,500 Skyhawks, Skylanes and Stationairs. These aircraft sport new paint schemes and detail improvements, but they look just like their predecessors. The general aviation market has not stood still, however, and this time around Cessna's singles face stiff competition from designs offering new technology.

Some of the biggest advances have been in the cockpit, and now Cessna has teamed with Garmin International to bring the latest in general aviation flightdeck technology to its piston singles. The availability of Garmin's G1000 all-glass integrated avionics marks perhaps the most radical change yet to these long-running aircraft.

Well known as a maker of GPS navigators, including the GNS 430 and 530 systems popular with general aviation pilots, Garmin set out to develop a complete integrated avionics suite. Its G1000 was first certificated earlier this year in the Diamond DA42 and has also been selected for Beechcraft and Mooney pistons. Cessna not only offers the G1000 as an option across its single-piston product line, but will use the system in its Citation Mustang entry-level business jet.

Clean design

The instrument panel is the most visible change in the G1000-equipped Cessna singles. Gone are the traditional round-dial flight instruments and Honeywell Bendix/King avionics stack. The G1000 panel features two large LCD control display units (CDU), measuring 265mm (10.4in) diagonally. The displays are identical and have a resolution of 1,024 x 768 pixels. One acts as the primary flight display (PFD) and one as the multifunction display (MFD).

Centred between the displays is a vertical digital audio panel that controls radio volume and intercom functions. Additionally, it is a marker beacon receiver and has a manual display reversion button should the automatic feature fail. Electrical system switches are to the left of the displays, while the entire right quarter of the panel is empty. The standby instruments, conventional altimeter, airspeed and vacuum-driven attitude gyro, are located below the CDUs. The Bendix/King KAP 140 dual-axis autopilot controller is located below the standby instruments. An optional ADF will be available soon, its control panel mounted below the autopilot's.

Most avionics boxes are no longer panel-mounted, they are racked in the aft fuselage. The heart of the system is a solid-state attitude and heading reference system (AHRS). This uses a unique three-dimensional magnetometer and dual GPS units to determine attitude information. The AHRS initialises itself rapidly, and in-flight initialisation at bank angles up to 20¼ is possible. In addition to dual navigation and communication (nav/comm) radios, the G1000 has dual GPS receivers.

Mounted behind the instrument panel is the engine/airframe unit, which acts as the interface between all aircraft sensors and G1000 systems. Additionally, it supplies the engine indication system (EIS) display to the CDUs. The EIS has three different windows, or pages. The "Default" page has round dial-like manifold pressure and RPM displays, as well as bar displays for fuel flow, oil pressure and temperature; cylinder head temperature and TIT as well as fuel quantity and electrical system information are also displayed. The "Lean" page is designed to aid proper leaning of the fuel mixture. "System" is the final EIS page and is used primarily for post-flight and diagnostic tasks.

Standard with the G1000 system in the Skylane is a traffic information system (TIS), which uses the Mode S transponder. While TIS provides awareness of other Mode S-equipped aircraft in the vicinity, it is not an active system like TCAS. Displayed traffic is not determined by interrogation of nearby transponders, rather it is uplinked from Mode S secondary radar sites. An active traffic advisory system, the Honeywell KTA 870, should be available soon.

The G1000 also has topographical and relative-terrain-mapping functions that provide a rudimentary terrain-avoidance capability. All terrain and obstacles are displayed on the MFD, or as an insert on the PFD. Unlike a Class B terrain awareness and warning system (TAWS), it is not predictive with audible alerts. The pilot must recognise the approaching obstacle or terrain and take the appropriate action. Garmin plans to field a Class B TAWS capability soon.

Flight impressions

Flight International was able to fly a T182T Turbo Skylane equipped with Garmin's G1000 integrated cockpit at Wichita's Mid-Continent airport. Gregory Pavlish, a manager at Cessna's air transport department, acted as the instructor pilot for the familiarisation flight. Having learned to fly in Cessna 150s and with nearly 200h dropping skydivers from old 182s, I immediately felt at home in the new Turbo Skylane. Before engine start the condition of the standby battery was checked. The battery provides 30min of power to the PFD, number one nav/comm and EIS in the event of engine alternator failure.

After engine start and avionics power-up, the AHRS initialised itself in less than 60s. The PFD was displayed on the left CDU, while the EIS and map display were shown on the right CDU. A route was entered into the flight management system (FMS) using the rotary cursor knob, on the lower right corner of the left CDU, to input waypoint characters one at a time. This proved to be tedious, and I would have preferred a keyboard or cursor control device to speed things along. Each CDU has an infrared receiver and Garmin plans to offer the option of using a PDA to load information into the FMS.

Before taking runway 14 for departure, Pavlish manually loaded the Skylane's rotation, best angle of climb, best rate of climb and glide speeds into the FMS. These speeds were then presented on the PFD's airspeed display, to the left of the attitude director indicator (ADI). Take-off and climb-out were hand flown. During the climb I found the PFD quite easy to interpret. Even in bright sunlight it was easy to read. The airspeed display is large, while a 6s trend vector aided precise airspeed control. The altimeter display is also well sized, with scale numbers easily read. The vertical velocity indicator (VVI) to the right of the airspeed was also easy to interpret. The ADI portion of the PFD in particular stands out. The aircraft symbol and two sidebars span from the airspeed indicator to the altimeter. In addition, the horizon line spans the entire screen, nearly 215mm. Instead of a conventional ball, a bar underneath the ADI's bank indicator shows slip.

Poor positioning

Once level at 4,500ft (1,370m), the autopilot was engaged. The 182 is designed for single-pilot operations, and while the autopilot was easy to reach, its location at the bottom of the instrument panel leaves much to be desired. The audio panel takes up prime real estate between the CDUs, a location perhaps better suited to the autopilot control panel. Additionally, the engaged or armed autopilot modes are not reflected on the PFD, and the auotpilot panel itself must be referenced to see what modes are controlling the aircraft.

This does not mean the KAP 140 is not a capable autopilot. What it does highlight is the need for integration in glass-cockpit aircraft. The barometric pressure needed to be set in three separate locations: PFD, standby altimeter and autopilot. Desired flight altitude could be set in the PFD and displayed on top of the altimeter presentation, but it was not relayed to the autopilot. Altitudes for the autopilot to capture had to be set in the autopilot panel itself. Desired headings for the autopilot's heading mode, however, were set via the "HDG" knob on the left side of CDU itself. Should Garmin field an autopilot for its G1000 avionics suite, there is ample room for improving the interface.

While still level at 4,500ft, I used the "Lean" page of the EIS to easily and properly lean out the mixture for the short cruise portion of the flight. Once cleared by ATC directly to HUT, our next waypoint, I pushed the "Direct" button on the left CDU. Selection of a direct course to HUT was fairly intuitive. Additionally, the active course's presentation on the right CDU's moving-map display confirmed that both the FMS and I thought we were going to the same point.

Scratch pad

Before reaching HUT, Pavlish requested radar vectors for an instrument landing system (ILS) approach to Wichita's runway 19R. With minimal guidance, I was able to load and activate the ILS approach procedure. The FMS put the ILS frequency into the number one nav radio's scratch pad, a nice feature.

The autopilot was engaged and used to fly the approach. On final it did an admirable job of tracking the localiserand glideslope. At minimums, 1,530ft (200ft above ground level), I disengaged the autopilot for a touch and go. Once back at 3,000ft, the autopilot was again engaged, and the next approach was loaded and activated - the RNAV (GPS area navigation) procedure to runway19R.

The RNAV approach was hand flown once inside the initial approach fix. Before the final approach fix, Pavlish simulated failure of the left CDU, and manually forced the right CDU into the reversionary mode. The PFD as well as the EIS were both now displayed on the right CDU. A small 50 x 50mm window in the lower left-hand corner of the CDU provided a thumbnail moving-map display. Course guidance was provided on the horizontal situation indicator, with the course deviation indicator tied to the RNAV course.

A left quartering headwind forced me to determine and fly the correct crab angle, as the G1000 does not have a flight director. While LNAV/VNAV (lateral/vertical navigation) minima are published to runway 19R, the G1000 does not provide vertical guidance and the higher LNAV minima were used. During the approach I found flying using the cross-cockpit display quite easy given the CDU's size and relatively small lateral displacement on the panel.

The third and final approach was again an RNAV (GPS) procedure to runway 19R. This time we requested clearance to fly the entire approach. The autopilot was engaged in the "NAV" mode, allowing it to follow the G1000's guidance. While the G1000/KAP 140 combination generally did a good job of tracking RNAV courses and procedures, the published holding pattern, for descent to the initial approach fix altitude of 3,600ft, threw it a loop. While the moving map, both CDUs now operable, showed the published procedure correctly, the autopilot would not fly it automatically. The autopilot flew the Skylane to the fix, but once there I had to manually select the HDG mode of the AP and initiate a turn for the proper entry into the holding pattern.

No surprises

On balance, this is a small inconvenience, given how capable the G1000 is, but it does emphasis that proper operation of this or any autoflight system is a serious task. One cannot assume how an autoflight system will function, it must be studied and practised to prevent surprises at night or in the weather. Once finally inbound to the final approach fix, the rest of the approach and full stop landing was uneventful.

Digital systems are far more reliable and easier to maintain than the electro-mechanical ones they replace. Increased processing power has allowed manufacturers to develop low-cost avionics suites with features such as moving maps, traffic information and terrain awareness. That glass cockpits will find a place in general aviation aircraft is a foregone conclusion, but not one without dangers. Nearly all pilots flying today learned their basic skills behind round-dial instrument panels.

One concern before I flew the Skylane was whether the advanced features resident in the G1000 avionics suite would compromise the usability of the PFD. Pitch and power are the fundamentals of instrument flight, and I found the large-scale ADI with its expansive horizon line provided a ready reference for determining and setting pitch attitude and bank angle. Airspeed and altitude trends were easily discerned on the PFD's tape-type displays. The EIS's manifold pressure and propeller RPM displays mimicked conventional round dials, and facilitated control of the turbocharged 235hp (175kW) Textron Lycoming engine.

Safety first

Safe and efficient use of the advanced features offered by the Garmin G1000 demands a dedicated training effort. Avionics suites with similar capabilities may have quite different operational procedures, and until they are standardised across the industry there will be no substitute for in-depth familiarisation with each specific suite. While GPS has given accurate RNAV capabilities to even the lightest GA aircraft, the basic principles of dead reckoning navigation still apply.

One might well be able to master the G1000 by treating it like a video game, but once airborne there is no "reset" button. The pilot must not forget to look outside the cockpit: the view up here is awesome, and not all aircraft have Mode S transponders nor all obstacles known and plotted.

 Rivals Compared

 

Cessna T182T Turbo

 

Cirrus SR22-G2 Skylane    

Diamond DA40-180 Diamond Star

Lancair Columbia 350

 

Length

8.84m

7.92m

8.01m

7.68m

Span

10.97m

11.73m

11.94m

10.97m

Seats

4

4

4

4

Engine

Lycoming T10-540

Continental IO-550N

Lycoming IO-360

Continental IO-550N

TO power

@235hp

@310hp

@180hp

@310hp

Empty weight

915kg

1,020kg

740kg

1,045kg

MTOW

1,406kg

1,542kg

1,150kg

1,542kg

Max landing weight

1,338kg

n/a

n/a

1,465kg

Useful load

497kg

521kg

410kg

499kg

Fuel capacity

333 litres

307 litres

155 litres

-

Max speed

175kt

-

147kt

190kt

Cruise speed

158kt

180kt

137kt

-

Stall speed (flaps)

49kt

54kt

49kt

65kt

Climb rate

1,040ft/min

1,400ft/min

945ft/min

1,225ft/min

Max operating altitude

20,000ft

-

16,400ft

18,000ft

Take-off distance

422m

480m

464m

381m

Landing distance

411m

709m

638m

716m

Max range

1,641km

>1,850km

1,056km

2,440km

List price

$322,500*

$334,700

$229,500

n/a

*With optional Nav III avionics including G1000. All performance at maximum weights

 

Source: Flight International

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