TAWS vs. HeliTAWS

Posted Thursday, January 30 2014 as Blog, Q&A

Q&A with Graeme Rowe, Avionics Manager for Eagle Copters

TAWS vs. HeliTAWS

TAWS vs. HeliTAWS

The following is a progressive description of the different types of Terrain Awareness Warning Systems (TAWS) compared to Helicopter TAWS (HeliTAWS) explain to customers by Graeme Rowe, Avionics Manager for Eagle Copters.

Ground Proximity Warning System (GPWS)

            This system meets TSO-C151b and utilizes 6 different callout modes of operation, mode 1–6.  This system was one of the earlier systems to be put in place for fixed wing aircraft with no helicopter flight characteristics considered.

CLASS “B” TAWS

            This system meets TSO-C151b.  It is comprised of mode 1–3 of the GPWS system as well as newly developed features Forward Looking Terrain Avoidance (FLTA), Premature Descent Algorithm (PDA), and descent to 500 feet above terrain or nearest runway elevation during a non-precision approach voice callout.  This was the next phase of enhanced TAWS for fixed-wing with no helicopter flight characteristics considered.

CLASS “A” TAWS  

            This system meets TSO-C151b. It is comprised of mode 1–5 of the GPWS system as well as the newly developed features FLTA, PDA, descent to 500 feet above terrain or nearest runway elevation during a non-precision approach voice callout, as well as a terrain display system. This was the next phase of enhanced TAWS for fixed-wing with no helicopter flight characteristics considered.

HeliTAWS

                This system meets modes 1–6 and FLTA of TSO-C151b as well as the new TSO-C194 which was developed for TAWS with helicopter flight characteristics considered.

Are the Honeywell MK XXI and the MKXXII were the first to be certified for the new TSO-C194?

My reply has always been that their original design intent was for fixed-wing aircraft in mind and not helicopters and that the new TSO-C194 is written in very general terms which has allowed the MK XXI and the MK XXII to meet the requirements of TSO-C194 without taking into consideration the helicopter flight characteristics. 

I then start to explain that the SANDEL HeliTAWS is the first and only true TAWS system designed specifically with helicopter flight characteristics in mind. I explain that incorporating Sandel’s proprietary TruAlert technology, HeliTAWS enables pilots to take off, cruise, hover and land at off-airport locations without triggering nuisance alerts.

Exceeding the TSO-C194 compliance, HeliTAWS includes an easy-to-interpret, color, high-resolution display for 3D terrain, obstacles, flight plan, traffic overlay, TAS/TCAS display interface, Radalt Decent Altitude Callouts along with MIL-STD-3009 On-Demand NVIS compatibility and that all of this in a single installation is available at a fraction of the cost of the Honeywell systems as a matter of fact that I can install a dual system for a third of the cost of the MK XXII. 

I guess one other thing to add is that the Honewell KMD 850 MFD that was to display the MK XXII and MK XXI is no longer available and that with those systems you require to install a MFD where the ST3400H requires no additional real estate in the cockpit.  A win-win solution.

Eagle Copters Ltd. is a family-owned, second generation company founded in 1975 by Mel O’Reilly based at the Calgary International Airport in Calgary, Alberta, Canada. Under the guidance of Mel’s son Mike as President and CEO – Eagle Copters and its’ subsidiaries has become one of the most well respected helicopter companies around the globe. To learn more about Eagle Copters or contact them, please visit www.eaglecopters.com