Avionics manufacturer Honeywell will mark a milestone in flight management system (FMS) development when the Boeing 747-8 makes its maiden flight this year.
The next generation Boeing freighter and Gulfstream’s new G650 large cabin, ultra-long-range business jet are equipped with Honeywell’s Next Generation Flight Management System (NGFMS), a new software baseline four years in development. The G650 flew for the first time Dec. 4. The first flight of the 747-8 will mark the first simultaneous introduction of core FMS software into both the business aviation and air-transport segments.
Honeywell began FMS development in the mid-1970s and now supplies 15 distinct FMS software baselines flying on 14,000 or more aircraft. Adding new, FMS-based functionalities envisioned for the Next Generation Air Transportation System (NextGen) and Single European Sky ATM Research (SESAR) program will require the company to update and recertify each individual baseline.
“We look out there in the future, we see NextGen, we see SESAR coming to pass. We see that the criticality [of the FMS] is going to continue to increase,” said Chad Cundiff, Honeywell Aerospace vice president for Crew Interface Products. “When you talk about things like 4-D (trajectories), required time of arrival and trajectory based optimization, the flight management system is going to be right at the heart of a lot of that future.”
Cundiff elaborated, “With the pace of change in flight management system software likely to increase because of all this NextGen and SESAR work, it’s really hard to go through and update 15 different baselines and get those all recertified every time you have a new feature or functionality. We said, can we design a next generation flight management system that accommodates all those current platforms?”
Airframers Boeing and Gulfstream signed on to the concept as launch customers, he said.
Honeywell’s approach involves partitioning and abstraction of application software from the core FMS software. Certain aspects that may be unique to one platform, such as the pilot interface with the FMS system, are separate of the source code.
“We wanted to make the way the aircraft flies, the way the FMS optimizes performance, the way it does turns, the way it develops vertical paths we wanted to make that common,” Cundiff said. “But we can’t have the user interface on the Boeing 747-8 be the same as the Gulfstream G650. There’s training issues, pilot familiarity issues, market differences [involved].
“So we came up with way to abstract the user interface,” he explained.
“What that means is we have an ability to develop a user interface for each of these aircraft and that’s partitioned from the flight management system code. We can tack on user interfaces, unique aircraft inputs and outputs, via these abstraction layers. That allows us to then not change that core flight management system code, but develop new applications rapidly.”
The software is designed to DO-178B standard for safety criticality. It runs on the Deos partioned real-time operating system for the Primus Epic avionics of the G650. For the 747-8, the software runs on a Wind River RTOS in the same form factor box as in the current 747-400, Cundiff said. The update is accomplished by changing out three processor cards with a single processor card that runs the NGFMS.
“On the Boeing 747-8, pilots are going to see three MCDUs (multifunction control display units). The flight management computer is not going to look any different to the maintenance guy, but it’s all going to be NGFMS-enabled,” Cundiff said. “On the Gulfstream, they’re going to still have some of the graphical inputs they have today. They’re going to have the MCDUs like they have on the G450/550, but NGFMS is now inside of Epic.”
Boeing 747-400 operators can upgrade to the NGFMS by sending in their FMS boxes for the card change-out. Some additional wiring will be necessary for Future Air Navigation System (FANS) capability, as well as upgraded displays for operations such as Required Navigation Performance-Authorization Required (RNP AR). Honeywell is developing a new, color liquid crystal display MCDU for Boeing on the 747-8, but that is not required to access the NGFMS.
“We see a lot of 747-400 operators out there today, especially guys who use the aircraft for cargo and plan to keep it for a number of years. They like the aircraft, but they’re concerned about FANS operation, they’re concerned about RNP-type operations,” Cundiff said. “They want some of the other functionality that’s in NGFMS. A lot of the folks who are planning to keep their aircraft are planning to do this upgrade.” — Bill Carey
ADS-B ‘Critical’ Sites
Two of the four key sites designated for Automatic Dependent Surveillance-Broadcast (ADS-B) “critical services” achieved initial operational capability (IOC) in late 2009.
Critical services IOC was declared at FAA’s Louisville, Ky., Terminal Radar Approach Control (Tracon) facility on Nov. 19, and at the Houston Air Route Traffic Control Center on Dec. 17, according to Vincent Capezzuto, FAA director of Surveillance and Broadcast Services and ADS-B program manager.
IOC at the Philadelphia Tracon, the key site for interfacing with the Airport Surface Detection Equipment, Model X (ASDE-X) airport surface management system, is planned this month. The fourth site, Anchorage center, is scheduled to begin ADS-B critical services in April.
As required by the ADS-B ground system contract awarded to prime contractor ITT Corp. in August 2007, critical services use GPS position data from properly equipped aircraft for presentation on air-traffic controller displays, allowing controllers to provide radar-like aircraft separations. “Essential services,” the uplink from the ground to aircraft of traffic and weather information, first entered service in November 2008 in southern Florida.
Capezzuto said controllers at Louisville can now provide terminal aircraft separations using ADS-B fused with radar through a modified Common ARTS automation system. FAA currently uses a 3 nautical mile separation standard in the terminal area with terminal radar.
“We acquired the approval to do the terminal separation. This is a big deal,” he told Avionics Magazine.
“You go to Air Services Australia; they’re doing 5 nautical mile enroute (separation), non radar airspace. You go to Hudson Bay, Canada, under Nav Canada; they’re doing 5 mile separation, non radar airspace. Europe is pushing 5 nautical miles in non-radar airspace. We went right to our first key site and we acquired terminal separation services.”
The Houston center provides air-traffic control over the Gulf of Mexico. IOC for ADS-B critical services there supports 5 nautical mile separation in non-radar airspace, benefiting offshore oil support helicopters as well as overflying airliners. Some ADS-B ground stations in the Gulf are located on offshore oil platforms.
Petroleum Helicopters Inc. (PHI) is the first offshore operator to equip for ADS-B, and eight equipped helicopters flew IFR flight plans over the Gulf for the first time Dec. 17, Capezzuto said.
“We’ve segregated the airspace,” he said. “If you can file IFR, you go up to 5,000 feet and you go direct to the (offshore) platform.”
Achieving critical services at the two remaining key sites the Philadelphia Tracon and Anchorage center, covering Juneau, Alaska will drive release of FAA’s ADS-B rulemaking, on track for release in April, Capezzuto said. The rule will establish performance requirements for avionics needed to operate in an ADS-B environment.
The rule was signed by FAA Administrator Randy Babbitt in early December and at this writing was being reviewed by the Department of Transportation. After DoT review, it was to be sent for final approval to the Office of Management and Budget. — Bill Carey
1090, UAT Revisions
FAA on Dec. 2 issued revised Technical Standard Orders (TSO) C166b, setting minimum performance standards (MPS)for 1090 MHz Extended Squitter ADS-B and Traffic Information Service-Broadcast (TIS-B) equipment; and TSO-C154c for Universal Access Transceivers (UAT) operating on 978 MHz.
According to TSO-C166b, all 1090 MHz transponders and TIS-B equipment manufactured after Dec. 2, 2009 must meet minimum performance standards outlined in RTCA DO-260B, “Minimum Operational Performance Standards for 1090 MHz Extended Squitter Automatic Dependent Surveillance-Broadcast and Traffic Information Services-Broadcast,” Section 2.
Under TSO-C154c, UAT transceivers or diplexers manufactured after Dec. 2 must conform to RTCA DO-282B, “Minimum Operational Performance Standards for Universal Access Transceiver Automatic Dependent Surveillance Broadcast,” Section 2.
In both cases, FAA said it “may” accept manufacturers’ applications for TSO authorization based on prior revisions for up to six months after Dec. 2 “if we know that you were working against the earlier MPS before the new change became effective.”
The revised TSOs precede FAA’s ADS-B performance-based equipage rule, which is expected to be issued in April. “We’re on schedule for our April 2010 release date from a rulemaking perspective,” Vincent Capezzuto, FAA’s ADS-B program manager, told Avionics in a late-December interview.
Seattle-based Horizon Air said it became the first regional passenger carrier to operate revenue flights using GPS Wide Area Augmentation System (WAAS) approach procedures.
Equipped with dual Universal Avionics UNS-1Ew flight management systems (FMS), Horizon Air Flight 2014, a 76-seat Bombardier Q400 turboprop, departed Portland, Ore., on Dec. 30 for arrival at Seattle-Tahoma Airport.
This was the first regional airline passenger flight with certified, WAAS-enabled FMSs providing guidance for a WAAS approach procedure. Later that day, a second Horizon flight became the first Part 121 passenger flight to complete a WAAS Localizer Performance with Vertical (LPV) guidance approach procedure.
“Reports of widespread IMC into Portland with the ILS to Runway 10R out of service resulted in a condition where only RNAV (GPS) WAAS approach procedures provided a means to land safely, on-time, at the original destination,” Universal Avionics said in a simultaneous announcement Jan. 8.
Horizon Air, sister carrier of Alaska Airlines, is upgrading its fleet of 40 Q400s with Universal’s WAAS-enabled FMS. FAA supplemental type certificate (STC) approval for installation of the UNS-1Ew system in the Q400 was issued Nov. 23.
The STC is owned by Canard Aerospace Corp., of Shakopee, Minn., which provided certification services and design engineering for the Horizon Air project.
“Horizon Air has long been committed to innovation and technical excellence, and we’re particularly proud to be spearheading the use of this new technology, which holds the promise of benefiting many thousands of customers in years to come,” said Jeff Pinneo, president and CEO.
Rockwell Collins was selected to provide avionics and pilot controls for the new MC-21 family of single-aisle airliners being developed by Russia’s Irkut Corp., Rockwell Collins announced Dec. 21. The first of three aircraft variants is due to enter service in 2016.
The avionics OEM will supply communications, navigation and surveillance systems, including the MultiScan Hazard Detection System weather radar; an Information Management infrastructure including electronic flight bags and docking stations; ARINC 664 hardware and configuration tools; and side-stick controls, rudder/brake pedal system, flap/slat and speed-brake control lever modules, and trim control panel.
Rockwell Collins won the packages together with Russian partner companies Concern Avionica for avionics components and Aviapribor for pilot controls.
The MC-21 will be manufactured by Irkut, which is part of United Aircraft Corp., in Irkutsk, Russia.
Era a.s., based in Fairfax, Va., said its Squid vehicle tracking units have been selected for Germany’s Frankfurt Airport. Era said 228 Squid units will support the airport’s advanced surface movement guidance and control system.
The units, ADS-B transponders mounted on top of airport vehicles, transmit vehicle locations and identification to air-traffic controllers ( Avionics, September 2008, page 42).
The units include an area management function that allows users to define boundaries in and around an airport where the units will automatically turn on and off transmissions.
Video System RTOS
Goodrich Sensors and Integrated Systems will use the Deos real-time operating system (RTOS) from DDC-I, of Phoenix, for its Concentrator and Multiplexor for Video (CMV) system, which is part of the Airbus A350 XWB External Cameras and Cockpit Video (ECCV) system.
Goodrich specified the Deos RTOS, OpenArbor development tools and DO-178B certification artifacts. Deos is a time-and-space partitioned RTOS built for safety critical applications.
“Deos provides the lowest risk, lowest cost and fastest path to avionics certification of any COTS RTOS. Deos has already been certified to DO-178B Level A in dozens of programs and flies on more commercial and military airframes than any other certifiable COTS RTOS,” said Greg Rose, DDC-I vice president of marketing.
The OpenArbor development system features C and C++ optimizing compilers, a source editor, project management support, automated build utilities and a mixed-language, multi-window symbolic debugger.
Mini Mode S
Trig Avionics, based in Edinburgh, U.K., announced a new miniature high-power Mode S transponder, the TT22, for high-performance aircraft.
The TT22 is based on the design of the company’s TT21 Mode S transponder for light aircraft. The key difference is that transmitted output power of the TT22 is higher, qualifying the unit as a Class 1 transponder, Trig Avionics said. Class 1 transponders are used for aircraft cruising faster than 175 knots and operating above 15,000 feet.
The TT22 is EASA ETSO and FAA TSO approved for IFR and VFR flight and is capable of extended squitter ADS-B Out transmission. Weighing less than 500 grams, it consists of a front panel controller with a separate transponder block. The list price of the unit is £1875 ($3,004).
Guardrail SIGINT Aircraft Makes Milestone
Northrop Grumman and the U.S. Army completed electromagnetic interference/electromagnetic compatibility (EMI/EMC) testing on the first RC-12X Guardrail signals intelligence (SIGINT) aircraft, according to an announcement Jan. 5.
EMI/EMC testing is required before an airworthiness certificate can be issued for the modified Hawker Beechcraft King Air turboprop. The testing validates operation of the aircraft’s electronic systems in a large, electromagnetically shielded chamber. Various combinations of the avionics and sensor payload equipment are operated independently and simultaneously to identify potential sources of interference or compatibility issues that can affect operations.
Northrop Grumman in 2007 was awarded a five-year contract from the Army to modernize 33 existing aircraft to a common standard and improve their signals collection and targeting capabilities (Avionics, April 2009, page 28).
The recent test was one in a series of successful assessments before delivery of the RC-12X to the Army, scheduled for this summer. Subsystem tests were underway in Northrop Grumman’s Systems Integration Labs in Sacramento, Calif. Ground testing of communications links and basic system functionality was to begin in January, with flight testing to follow.
“This test is a major milestone both for the Army and for Northrop Grumman as we work toward fielding the improved system in 2010,” said Trip Carter, director of Northrop Grumman’s Airborne Intelligence, Surveillance and Reconnaissance (AISR) initiatives.
Meanwhile, the U.S. Air Force’s new MC-12W Project Liberty aircraft arrived at Bagram Air Base in Afghanistan in late December. The Air Force plans to operate 37 of the King Air 350 and 350ERs modified with full-motion video and SIGINT payloads. The integration is managed by the L-3 Communications Mission Integration Division, and includes Hawker Beechcraft, Alliant Techsystems and Northrop Grumman as partners.
Defense Secretary Robert Gates authorized Project Liberty in July 2008 to quickly supplement Air Force intelligence, surveillance and reconnaissance (ISR) assets. The L-3 team was contracted in September that year.
The aircraft flew its first combat mission over Iraq on June 10, 2009.
Boeing completed the first phase of flight testing of a B-1 bomber upgraded with new digital avionics under the Fully Integrated Data Link (FIDL) program.
The Phase I flight test concluded Oct. 16; it included nine sorties performed by the U.S. Air Force at Edwards Air Force Base, Calif. Phase 1 included observations of crew acclimation to the new cockpit configuration; hardware temperature and vibration tests; and functionality tests of display-related software upgrades, including moving maps.
Also last October, Boeing received an $84 million contract for B-1 avionics software Sustainment Block 16, one of the continuous updates since the aircraft entered service in 1989.
The FIDL upgrade includes new processors, color displays and communications architecture. The upgrade integrates beyond line-of-sight and line-of-sight data links and reduces crew workload by re-tasking missions, eliminating the need for steps such as manual entry of weapons data for targeting.
First flight with the data link was achieved July 29, 2009.
Eric Vanderslice, Boeing B-1 FIDL program manager, said the upgrade replaces 25-year-old avionics, including replacement of CRT displays with flat-panel displays.
The flight test B-1 was destined for Tinker Air Force Base, Okla., for programmed depot maintenance. Remaining software flight-test objectives will be performed during FIDL Phase 2, scheduled to begin at Edwards AFB in April and run for 10 months.
The Air Force is expected to award a contract in November for the production of FIDL installation kits for the service’s fleet of 66 B-1s, according to Boeing.
Curtiss-Wright Controls, Charlotte, N.C., on Dec. 21 announced a $16 million acquisition of Skyquest Systems Ltd., of Basildon, U.K., supplier of aircraft video displays, recorders and video/radar converters for surveillance aircraft. The business will become part of Curtiss-Wright’s Embedded Computing group.
“The addition of Skyquest’s airborne video solutions to our product family will expand our systems offering for customers looking for a total solutions provider for their mission critical applications,” said David Adams, Curtiss-Wright Corp. co-chief operating officer. “Furthermore, Curtiss-Wright Controls will be able to grow the Skyquest brand by providing it access to many new markets.”
Skyquest Systems had estimated 2009 sales of $8 million. Skyquest products include the Video Management System, enabling observers and pilots to independently select, view and record images. The system accommodates multiple camera sensor outputs, which can be viewed simultaneously, and supports touch-screen control of moving maps, video recorders and mission computers. Skyquest also produces High Definition video recorders for airborne surveillance.
Ducommun Inc., Carson, Calif., said its Miltec Corp. subsidiary was issued a United States patent for an inertial/magnetic measurement (IMU) device for missiles. The technology was described as enabling development of remote target location systems with accuracies and robustness beyond that of conventional digital compassing systems.
The Miltec IMU utilizes magnetometers to very accurately determine pitch, roll and heading, while using commercial off-the-shelf microelectromechanical gyros. It will be part of Miltec’s Mini3x inertial navigation product line, applicable for small satellites, unmanned ground and air vehicles and missiles.
“The ability to develop specialized design, engineered components and subsystems for missile defense was one of the capabilities Ducommun hoped to develop through the Miltec acquisition,” said Joseph C. Berenato, Ducommun chairman and CEO.
“This patent for the IMU demonstrates that we are beginning to deliver on that promise. This movement toward design engineered product and services is a strategic goal of Ducommun.”
Fire Scout Video
The MQ-8B Fire Scout Vertical Unmanned Aircraft System (UAS), designated P7, in November demonstrated interoperability with the U.S. Army’s One System Remote Video Terminal (OSRVT) at Yuma Proving Ground, Ariz.
Developer Northrop Grumman said the demonstration, which took place the week of Nov. 23, was one in a series to prepare the Fire Scout for participation in the Army Expeditionary Warrior Experiment (AEWE) at Fort Benning, Ga., in January and February.
The OSRVT provides direct receipt of full-motion video and targeting metadata by capturing the Omni broadcast from UAS within a unit’s area of operations.
“Working with the OSRVT team, we were able to integrate the sensor downlink from the Fire Scout into the rugged manpack system for display to the user,” said Mike Roberts, Class IV UAV chief engineer with Northrop Grumman’s Aerospace Systems sector.
“This integration was accomplished quickly without making any changes to the Fire Scout’s current datalink or air-to-ground interface.”
SpaceAge Control, Palmdale, Calif., was selected by Insitu to provide the miniature pitot-static probe for the Integrator unmanned aircraft system (UAS). The 4207 series probe provides primary air data pressure information required by the aircraft.
SpaceAge Control said the patented probe design addresses the unique requirements of long-duration, smaller-sized aircraft such as UAVs and light jets.
The catapult-launched Integrator, Insitu’s latest UAS, weighs 135 pounds (maximum takeoff weight) with a combined payload bay capacity of 50 pounds. Its modular payload design allows for plug-and-play integration of different payloads.
Among recent developments, Insitu, of Bingen, Wash., in December said it successfully flew the L-3 Communications West “Bandit” digital data link on Integrator. Bandit is Advanced Encryption Standard capable and Remote Optical Video Enhanced Receiver (ROVER) 4 and 5 compatible. Last October, Insitu and Harris Corp. demonstrated a single-channel ground and airborne UHF/VHF relay system, based on the Harris Falcon III (AN/PRC-152) radio.
âž¤ Lockheed Martin on Jan. 6 signed a $118 million foreign military sales contract to deliver Sniper Advanced Targeting Pods (ATP) and LANTIRN Enhanced Resolution navigation pods to the Turkish Air Force’s F-16 Block 40 and Block 50 Peace Onyx aircraft. The Sniper ATP will provide enhanced target detection and identification capability, providing long-range, positive identification of both moving and stationary air and ground targets.
âž¤ Lockheed Martin Systems Integration, Owego, N.Y., was awarded an $82 million contract modification for the production and delivery of common cockpits for MH-60S Lot 12 Knighthawk and MH-60R Lot 8 Seahawk helicopters. The modification provides for long lead items to support MH-60S Lot 13 and MH-60R Lot 9 kits.
âž¤ AeroVironment, based in Monrovia, Calif., received a $23.9 million order under an existing contract to upgrade existing analog Raven UAS systems currently being used by the U.S. Army and Marine Corps with AV’s digital data link. The potential value of the order is $66.6 million.
âž¤ Boeing received a $23 million contract from the U.S. Air Force for Phase 2 of the B-1 Laptop Controlled Targeting Pod software upgrade. The upgrade adds additional capability to the B-1 bomber’s targeting system by allowing it to more accurately identify both stationary and moving targets, Boeing said. The software is expected to enter testing in 2011.
âž¤ Lockheed Martin received a $17.8 million contract from the U.S. Air Force for a software upgrade that integrates critical communications and situational awareness capabilities into the A-10C close air support fighter. The software upgrade is the third in an annual series planned for the A-10 and is scheduled for release in May 2011. The earlier two upgrades were also performed by Lockheed Martin; the first was fielded in May 2009 and the second is planned for release in May 2010.
âž¤ Lockheed Martin in December announced a $14.75 million contract from the U.S. Navy to integrate a digital messaging interface that will improve the flow of data from MH-60R anti-submarine warfare helicopters to Navy ships across the new Ku-Band tactical data link.
âž¤ McDonnell Douglas was awarded a $12.4 million contract from the U.S. Navy for 12 months of avionics repair facility support, providing for repair of various F/A-18 components. The announcement involves a foreign military sale to Spain, Kuwait and Malaysia, of less than 1 percent, according to the Navy.
âž¤ Northrop Grumman was awarded a $12 million contract from the U.S. Navy for component parts of the Navy’s large aircraft infrared counter measure system, the AN/AAQ-24 (V) 25, supporting H-46 and H-53 helicopters. Work will be in Rolling Meadows, Ill., and is expected to be completed by 2011.
âž¤ Cobham was awarded an $11.5 million contract from the U.S. Navy for the Band 5-6 Replacement Amplifier, a component of the ALQ-99 electronic warfare equipment carried by U.S. Navy EA-6B Prowler and EA-18G Growler aircraft. Work will be performed by Cobham Sensor Systems in Lansdale, Pa.
âž¤ Vision Systems International (VSI), LLC received a $6.7 million contract for Night Vision Cueing and Display units, including hardware and associated support equipment, from the Naval Air Systems Command in Patuxent River, Md. Under terms of the agreement, VSI will provide image intensified night vision with symbology insertion, expanding the capability of the Joint Helmet Mounted Cueing System for 24-hour operations.
âž¤ Southeast Aerospace (SEA), of Melbourne, Fla., an avionics distributor and MRO facility with PMA manufacturing capability, announced plans Jan. 5 to acquire Global Aerospace Consulting, a systems design, integration, certification and technical publication company. Under terms of the acquisition, SEA has acquired all supplemental type certificates, processes and formats from Global Aerospace Consulting.
âž¤ T eledyne Controls, of El Segundo, Calif., signed a contract with AirAsia X, the long haul low-cost affiliate of AirAsia, to provide Wireless GroundLink Quick Access Recorders for 25 new Airbus A330s and for retrofit on two A340s. The airline also selected Teledyne’s Flight Data Monitoring Services to automate the recording and air-to-ground wireless transfer of aircraft data.
âž¤ Dubai Aerospace selected the Flight Data Interface Management Unit from Teledyne Controls as a standard option for its new fleet of 70 Airbus A320s. The unit will be used for flight-data acquisition, aircraft condition monitoring and data recording.
âž¤ Rockwell Collins was selected by Dubai airline flydubai to provide avionics and data link communications for 54 Boeing 737 NGs. The selected avionics include the HGS-4000 Head-Up Guidance System, MultiScan Hazard Detection System weather radar, and Hermes 2100 Ground Data Link system.
âž¤ Latin American airline GOL Linhas Aéreas Inteligentes S.A. will deploy the navAero tBag C22 Electronic Flight Bag on its B737 NGs. The contract is part of GOL’s implementation of a program for fleet-wide ACARS-through-Iridium reporting and management of messages.
âž¤ Embedded computer manufacturer Kontron, of Poway, Calif., in December announced an expanded distribution agreement with Arrow Electronics, of Melville, N.Y. Under the agreement, Arrow will market and distribute Kontron’s line of embedded computing products in North and Central America.
The agreement extends an existing relationship between the companies focused on Kontron’s carrier grade and rack mount servers.
âž¤ Libyan airline Afriqiyah Airways will install the OnAir in-flight connectivity solution on its fleet of Airbus long- and short-haul aircraft. This is the first airline to announce connectivity system installations on both long and short haul fleets, according to Geneva-based OnAir, a joint venture of Airbus and SITA.
In phase one of the agreement, OnAir will install the full connectivity suite on widebody A330s. In phase two, Mobile OnAir will be installed on the airline’s narrowbody A320/A319s.
âž¤ The Cobham HeliSAS Stability Augmentation System and Autopilot received FAA Technical Standard Order authorization. Cobham was in the process of obtaining HeliSAS certification on the Bell 206 and 407, Eurocopter AS350, and U.S. Navy TH-57 helicopters.