Face coverings at the MPF, CAC/DEERS, ID cards, Commissary, BX and Shopette are mandatory!  All Civilian, Active Duty members and dependents are reminded to avoid visiting the Commissary, Base Exchange, Bldg 3000 and the Pharmacy on Wednesdays. Retirees are also being seen on Wednesdays at the CAC/DEERS office by appointment only.  Please call 661-277-4281 option 3, to make an appointment. Retirees may also utilize base facilities on Sundays.

418th FLTS working to keep KC-135s flying

Testers pack into a KC-135 Stratotanker’s cockpit to conduct ground testing of Traffic Collision Avoidance System version 7.1. last month. The Air Force’s KC-135 fleet will need the upgraded TCAS in order to fly over Europe beginning Jan. 1, 2017. (U.S. Air Force photo by Chris Higgins)

Testers pack into a KC-135 Stratotanker’s cockpit to conduct ground testing of Traffic Collision Avoidance System version 7.1. last month. The Air Force’s KC-135 fleet will need the upgraded TCAS in order to fly over Europe beginning Jan. 1, 2017. (U.S. Air Force photo by Chris Higgins)


By January 1, 2017, the European Union is requiring all existing aircraft to have Traffic Collision Avoidance System version 7.1 installed on aircraft entering its airspace. TCAS monitors the airspace around a plane for other aircraft independent of air traffic control and warns pilots of the presence of other transponder-equipped aircraft, which may pose a midair collision situation.

TCAS is generally required on all aircraft larger than 12,500 pounds and/or on planes that carry more than 19 passengers.


The system is installed to prevent close calls and midair collisions by notifying pilots of approaching aircraft with attention signals and commands, both audio and visual. Pilots are notified with TAs and RAs – traffic advisories and resolution advisories. TAs are for situational awareness and RAs are instructions to the pilot on what maneuver to make.


About 30 testers led by the 418th Flight Test Squadron are working to test the upgraded TCAS 7.1 for the Air Force’s KC-135 Stratotanker fleet, which current uses TCAS 7.0 software.

“Having TCAS 7.1 will allow [the U.S. Air Force] to fly the KC-135 in European airspace,” said 2nd Lt. Renner Mead, 412th Operations Group executive officer and lead test conductor. “Starting January, 1 2017, we cannot fly KC-135s in Europe without this. The last flight safety brief by the wing was pretty much all about TCAS. There have been a lot of close calls in the local area and around the country.”


The TCAS and Identification Friend or Foe systems work together to detect other airplanes and determine potential threats. Depending on flight levels and closure rates of aircraft, the TCAS sensitivity changes to reduce nuisance traffic advisories and resolution advisories. Traffic advisories warn pilots of threat and resolution advisories command the pilot to descend, climb, or level off to avoid threat. Other non-threat traffic is also displayed to the pilot.


“Just like how a policeman can detect how fast you’re going with a radar gun, TCAS uses a similar concept to determine closure rates. The closure rates along with other aircraft data are used in the logic to calculate the closest point of approach and trigger TA/RAs when needed.” said Alex Regalado, 418th FLTS flight test engineer.


Testing TCAS 7.1 on the ground can be complicated with a traditional ramp tester. Ground tests require the KC-135 to be connected to test equipment to simulate that it’s flying. In addition, other test equipment is used to simulate approaching aircraft (also known as intruders) to try and trigger the TCAS alerts. Some simulated flight scenarios require both aircraft, KC-135 and intruder, to climb or descend at a certain time with correct geometries to trigger alerts.


“An air data test set has to be connected to the aircraft pitot system via tubes to simulate the airplane flying at a certain pressure altitude and air speed. Additionally, a radar altimeter test set has to be connect to the aircraft radar altimeter via radio frequency coaxial cables to simulate the aircraft above ground level altitude. A flight line ramp tester has to be used to simulate the intruder flight path,” Regalado said.  “The flightline ramp tester has to be pointed at the aircraft to the let the KC-135 know that there’s an intruder coming at it from a certain azimuth.”


The test team’s main goal during the ground test is to test TCAS 7.1 software before the test flights by triggering different RAs during various flight scenarios.


The updated version has a few new features including specific commands for clarity and improved reversal software in vertical chase situations.


“In the reversal feature, if two airplanes are close and the TCAS 7.1 issues an RA, and one plane doesn’t listen, then the other plane will be given a command to go the other way; it’s more intelligent,” Mead said.


The KC-135 pilot has the option of putting TCAS on TA mode only or standby during aerial refueling, which eliminates the nuisance resolution advisories when the plane is conducting is primary mission.


Along with the heavy importance of testing and certifying TCAS 7.1, an additional challenge is facing the testers and the KC-135 fleet entirely. The current box and processor that holds the TCAS 7.0 is being discontinued by the current contracted manufacturer.


“The box that holds the TCAS is going obsolete and we need to certify the new box and processor as well,” said Mead. “We lose 10 TCASs everyone month within the entire fleet of 400 KC-135s. Right now, we have a stockpile of current boxes to do maintenance like we normally would, but without certifying the new box, we would be losing 10 jets every month once we deplete the supply of current boxes.”


Ground testing of TCAS 7.1 has made way for flight tests last week using a T-38 to try and trigger advisories in the air like it’s supposed to.


USAF Comments Policy
If you wish to comment, use the text box below. AF reserves the right to modify this policy at any time.

This is a moderated forum. That means all comments will be reviewed before posting. In addition, we expect that participants will treat each other, as well as our agency and our employees, with respect. We will not post comments that contain abusive or vulgar language, spam, hate speech, personal attacks, violate EEO policy, are offensive to other or similar content. We will not post comments that are spam, are clearly "off topic", promote services or products, infringe copyright protected material, or contain any links that don't contribute to the discussion. Comments that make unsupported accusations will also not be posted. The AF and the AF alone will make a determination as to which comments will be posted. Any references to commercial entities, products, services, or other non-governmental organizations or individuals that remain on the site are provided solely for the information of individuals using this page. These references are not intended to reflect the opinion of the AF, DoD, the United States, or its officers or employees concerning the significance, priority, or importance to be given the referenced entity, product, service, or organization. Such references are not an official or personal endorsement of any product, person, or service, and may not be quoted or reproduced for the purpose of stating or implying AF endorsement or approval of any product, person, or service.

Any comments that report criminal activity including: suicidal behaviour or sexual assault will be reported to appropriate authorities including OSI. This forum is not:

  • This forum is not to be used to report criminal activity. If you have information for law enforcement, please contact OSI or your local police agency.
  • Do not submit unsolicited proposals, or other business ideas or inquiries to this forum. This site is not to be used for contracting or commercial business.
  • This forum may not be used for the submission of any claim, demand, informal or formal complaint, or any other form of legal and/or administrative notice or process, or for the exhaustion of any legal and/or administrative remedy.

AF does not guarantee or warrant that any information posted by individuals on this forum is correct, and disclaims any liability for any loss or damage resulting from reliance on any such information. AF may not be able to verify, does not warrant or guarantee, and assumes no liability for anything posted on this website by any other person. AF does not endorse, support or otherwise promote any private or commercial entity or the information, products or services contained on those websites that may be reached through links on our website.

Members of the media are asked to send questions to the public affairs through their normal channels and to refrain from submitting questions here as comments. Reporter questions will not be posted. We recognize that the Web is a 24/7 medium, and your comments are welcome at any time. However, given the need to manage federal resources, moderating and posting of comments will occur during regular business hours Monday through Friday. Comments submitted after hours or on weekends will be read and posted as early as possible; in most cases, this means the next business day.

For the benefit of robust discussion, we ask that comments remain "on-topic." This means that comments will be posted only as it relates to the topic that is being discussed within the blog post. The views expressed on the site by non-federal commentators do not necessarily reflect the official views of the AF or the Federal Government.

To protect your own privacy and the privacy of others, please do not include personally identifiable information, such as name, Social Security number, DoD ID number, OSI Case number, phone numbers or email addresses in the body of your comment. If you do voluntarily include personally identifiable information in your comment, such as your name, that comment may or may not be posted on the page. If your comment is posted, your name will not be redacted or removed. In no circumstances will comments be posted that contain Social Security numbers, DoD ID numbers, OSI case numbers, addresses, email address or phone numbers. The default for the posting of comments is "anonymous", but if you opt not to, any information, including your login name, may be displayed on our site.

Thank you for taking the time to read this comment policy. We encourage your participation in our discussion and look forward to an active exchange of ideas.