Avionics Design Newsletter Archives | Page 2 of 2

Can Batteries Be Maintenance Free?

Feb 24, 2016

by David Jensen

Well, perhaps not totally so. However, one manufacturer is applying a chemistry and design that takes battery operation a step closer to a maintenance-free goal.

Lithium-ion (Li-ion) batteries have become ubiquitous, powering everything from smart phones to electric-powered automobiles. They can be found in aircraft, too, in portable radios, electronic flight bags and the laptop computers pilots bring on board for flight planning and check lists. Li-ion batteries have been used in military aircraft for years—for engine starts, emergency power and other functions—and they have become widely employed in unmanned air vehicles. They serve as main-ship batteries in the Boeing F-18, Lockheed Martin F-35, Sikorsky CH-53K and Northrop Grumman Global Hawk, among other aircraft.

However, Li-ion batteries have yet to reach their full potential in the civil aviation arena. This is primarily because new-technology batteries require extensive effort and money to prove they meet certification requirements.

But the use of Li-ion batteries in aircraft may soon become widespread after more light is shed on their benefits. These rechargeable power units—in which lithium ions move from the negative electrode to the positive electrode during discharge and move the opposite direction during charging—represent the latest generation in the evolution of aircraft batteries. They succeed those utilizing lead-acid and nickel-cadmium (NiCad) chemistries, both more than a century old.

Improved battery technology has become more and more vital, not only to perform conventional functions such as engine starts, power stabilization and running onboard electrical systems, but also to supply an ever-growing number of systems in what many commonly call “the more electric airplane.” To give just one example of this trend, Honeywell and Safran have partnered to develop electrically controlled taxiing for commercial aircraft, to allow engine startups away from the gate thus reducing fuel consumption.

A relatively new (introduced as a product in the 1970s) and therefore emerging technology, Li-ion offers advantages over lead-acid and NiCad technologies. Newer aspects of Li-ion technology can provide greater energy density, more consistent power delivery, environmental benefits and reduced weight, among other gains. They also can reduce battery maintenance significantly, in part by simplifying and reducing the required number of battery checks. Indeed, new versions of Li-ion chemistry may some day reduce the need for dedicated battery shops at fixed-base operations (FBOs).

Bit of Controversy

A relatively new technology invariably draws controversy, however. In the field of consumer goods, a spate of incidents occurred late last year in which the Li-ion batteries on hoverboards—essentially self-balancing, powered scooters—burst into flames during recharge mode. It prompted airlines to bar stowing hoverboards on board their aircraft.

In the aviation field, two operators of the Boeing 787 Dreamliner, All Nippon Airways and Japan Airlines, made emergency landings in January 2013 because the lithium metal oxide batteries in the new-design aircraft overheated, released electrolyte vapors and created oxygen within their cases. The incidents resulted in internal thermal runaway, or accelerated heat buildup, that created fire outside the batteries’ steel cases. The National Transportation Safety Board (NTSB) cited “deficiencies in the [battery’s] design and certification processes” as the overall reason why the incidents occurred.

The 787 has two lithium metal oxide batteries onboard that provide backup power. Their malfunction invoked a three-month, fleet-wide grounding. Boeing had the battery installation redesigned, and in April 2013 the FAA gave the 787 fleet the green light to fly.

[fullwidth background_color=”” background_image=”” background_parallax=”none” enable_mobile=”no” parallax_speed=”0.3″ background_repeat=”no-repeat” background_position=”left top” video_url=”” video_aspect_ratio=”16:9″ video_webm=”” video_mp4=”” video_ogv=”” video_preview_image=”” overlay_color=”” overlay_opacity=”0.5″ video_mute=”yes” video_loop=”yes” fade=”no” border_size=”0px” border_color=”” border_style=”” padding_top=”20px” padding_bottom=”20px” padding_left=”0px” padding_right=”0px” hundred_percent=”no” equal_height_columns=”no” hide_on_mobile=”no” menu_anchor=”” class=”” id=””][title size=”1″ content_align=”left” style_type=”double” sep_color=”” margin_top=”” margin_bottom=”” class=”” id=””]CURRENT ISSUE[/title][one_third last=”no” spacing=”yes” center_content=”no” hide_on_mobile=”no” background_color=”” background_image=”” background_repeat=”no-repeat” background_position=”left top” hover_type=”none” link=”” border_position=”all” border_size=”0px” border_color=”” border_style=”” padding=”” margin_top=”” margin_bottom=”” animation_type=”” animation_direction=”” animation_speed=”0.1″ animation_offset=”” class=”” id=””][imageframe lightbox=”no” lightbox_image=”” style_type=”bottomshadow” hover_type=”none” bordercolor=”” bordersize=”0px” borderradius=”0″ stylecolor=”” align=”center” link=”https://www.avm-mag.com/wp-content/mag/flipbooks/AVM-2016-02-DIGITAL/index.php#Aviation_Maintenance_Magazine/page2-page3″ linktarget=”_blank” animation_type=”0″ animation_direction=”down” animation_speed=”0.1″ animation_offset=”” hide_on_mobile=”no” class=”” id=””] [/imageframe][separator style_type=”none” top_margin=”” bottom_margin=”20″ sep_color=”” border_size=”” icon=”” icon_circle=”” icon_circle_color=”” width=”” alignment=”” class=”” id=””][/one_third][one_third last=”no” spacing=”yes” center_content=”no” hide_on_mobile=”no” background_color=”” background_image=”” background_repeat=”no-repeat” background_position=”left top” hover_type=”none” link=”” border_position=”all” border_size=”0px” border_color=”” border_style=”” padding=”” margin_top=”” margin_bottom=”” animation_type=”” animation_direction=”” animation_speed=”0.1″ animation_offset=”” class=”” id=””][title size=”2″ content_align=”left” style_type=”underline” sep_color=”” margin_top=”” margin_bottom=”” class=”” id=””]IssueHighlights:[/title][checklist icon=”” iconcolor=”#81d742″ circle=”no” circlecolor=”” size=”18px” class=”” id=””][li_item icon=””]Getting schooled by Robinson[/li_item][li_item icon=””]The Care and Feeding of Batteries[/li_item][li_item icon=””]Lithium Ion Batteries[/li_item][li_item icon=””]Intelligence: News[/li_item][li_item icon=””]Intelligence: About People[/li_item][li_item icon=””]Intelligence: Aviation Electronics News[/li_item][li_item icon=””]2016 Aviation Maintenance Repair Center Directory[/li_item][li_item icon=””]NEW! Aviation Maintenance Buyer’s Guide[/li_item][/checklist][/one_third][one_third last=”yes” spacing=”yes” center_content=”no” hide_on_mobile=”no” background_color=”” background_image=”” background_repeat=”no-repeat” background_position=”left top” hover_type=”none” link=”” border_position=”all” border_size=”0px” border_color=”” border_style=”” padding=”” margin_top=”” margin_bottom=”” animation_type=”” animation_direction=”” animation_speed=”0.1″ animation_offset=”” class=”” id=””][imageframe lightbox=”no” lightbox_image=”” style_type=”bottomshadow” hover_type=”none” bordercolor=”” bordersize=”0px” borderradius=”0″ stylecolor=”” align=”center” link=”http://www.avm-mag.com/wp-content/uploads/2016/01/AVM_Calendar_2016_FINAL_v10_LORES.pdf” linktarget=”_blank” animation_type=”0″ animation_direction=”down” animation_speed=”0.1″ animation_offset=”” hide_on_mobile=”no” class=”” id=””] [/imageframe][separator style_type=”none” top_margin=”” bottom_margin=”20″ sep_color=”” border_size=”” icon=”” icon_circle=”” icon_circle_color=”” width=”” alignment=”” class=”” id=””][fusion_text]NEW – the large fold out 2016 Wall planner was inserted into the Dec/Jan issue but you can also click/view above.[/fusion_text][/one_third][/fullwidth]

Drones in Maintenance: The New Frontier

Feb 24, 2016

By Ryan Aggergaard

After a flurry of activity at the end of 2015 and the beginning of 2016, the United States finds itself in the midst of an emerging (if slowly) regulatory regime governing the use of Unmanned Aircraft Systems, also known as UAS or, more commonly, “drones.” Although the FAA is still working through the process of integrating UAS into the National Airspace System (NAS), a regime is beginning to emerge that gives UAS operators a better idea of what is expected of them in order to operate UAS safely and remain compliant.

For those in the maintenance world, there are a few now-established rules and guidance that one should be aware of if seeking to work with or on drones in the future. Note that these requirements apply to small UAS (those under 55 pounds) where the FAA seems to be currently focusing most of its attention.

Use in Maintenance

There have been a number of stories recently of drones being used to perform inspections of aircraft as part of the maintenance process. The appeal of this method is quickly apparent, as it allows an individual to rapidly inspect an aircraft from the ground without the need for mechanical lift equipment or stands that must be moved along the length of the aircraft in order for an individual to see all angles of the aircraft. However, before grabbing a drone and a GoPro and going to work, it is necessary to consider a number of practical and legal issues presented by this technology.

From a practical perspective it is necessary that only individuals with the proper training be permitted to operate a UAS used for inspection. There are at least two reasons for this: first, it is important to avoid a scenario in which a mis-controlled drone strikes the aircraft being inspected, causing or exacerbating damage, or strikes equipment or persons at the maintenance facility causing damage or injury. (A quick YouTube search will reveal the shocking number of ways people can find to crash a drone.) Second, it is vital that the person operating the drone for purposes of inspection is able to satisfy the inspection requirements established by the applicable manuals.

At this point it is necessary to establish an important line of demarcation between practical and legal concerns. If you are seeking to use a drone for inspection purposes in your maintenance facility, and your operations occur exclusively indoors, the FAA’s jurisdiction over your use of drones is practically nothing. This is because the FAA’s authority—and the NAS—do not extend inside of buildings and hangars. It is only when you operate a drone outside that the FAA’s statutory authority kicks in and you become subject to its regulations. Therefore, if you wish to use a drone indoors for the purposes of inspection, you are free to do so, provide you take the necessary precautions to guard against injury and other liability.

Once you step (or fly) outside—and into the FAA’s jurisdiction—a significant set of regulations attach, or will soon attach. This is because the FAA regulates the use of UAS when they are operated for business purposes. The same practical considerations apply.

As of this writing, the FAA’s Small UAS Notice of Proposed Rulemaking is still being dispositioned. That means that in order to operate a UAS for business purposes, you must still obtain from the FAA a Section 333 exemption. This exemption allows a business to legally operate a UAS for business purposes. The exemption includes a blanket Certificate of Waiver or Authorization that permits operation with certain restrictions. However, because most maintenance operations are based on or near airports, a specific COA addressing your particular airspace will also likely be necessary. This COA will spell out the specific operational parameters for your use of drones in the performance of inspection and maintenance.

Power Sources Charge Ahead

Feb 24, 2016

by Charlotte Adams

Aircraft batteries are too often taken for granted. That is, until a plane loses electrical power far from home and has to switch to its emergency back-up system. Fortunately the prevailing nickel cadmium and lead acid battery technologies are well understood, while evolving lithium chemistries are becoming more acceptable as proper safeguards are applied.

Battery technology continues to improve and batteries last longer. Maintenance and test equipment likewise continues to develop as microprocessors and software make the gear more capable, flexible, and upgradeable.

It’s hard to overemphasize the importance of batteries. As 14 CFR 23.1353 states, in the event of a complete loss of the primary electrical power generating system, the battery must be able to provide electrical power to loads that are essential to safe flight and landing. For aircraft certified to a maximum altitude of 25,000 feet, that means at least 30 minutes of battery power and for aircraft certified for higher altitudes, that means at least 60 minutes of battery power.

Yet batteries are almost an afterthought for some pilots. Battery-related accidents happen all too often, particularly in general aviation, where some pilots may fly their planes just a few hours a year. The rest of the time the battery may just be sitting there, losing charge and deteriorating without regular care and feeding. One day the pilot comes out, finds that the battery is dead, and then jump starts the aircraft from an external source. Up in the air after experiencing electrical failure, and with no backup battery power, the pilot is lucky to return unscathed. His airplane may be less lucky.

Never, ever jump start or hand-prop start an aircraft that is certified with a starting battery if the aircraft has a dead battery, warns Skip Koss, vice president of marketing with Concorde Battery, a leading manufacturer of sealed lead acid (SLA) batteries. He attributes “at least half a dozen” accidents to flying with dead batteries that were not properly recharged before flight. A dead battery’s state is unknown. It needs to be removed, checked, and charged before takeoff.

Lead Acid Batteries

Lead acid batteries have been around for more than 100 years and are still being used in one form or another by general aviation, military, and some smaller executive aircraft, not to mention conventionally powered automobiles. Unlike car batteries, however, aviation batteries are designed to be lightweight. They can’t take the level of abuse dealt out to automotive equipment. And they need more regular test and maintenance.

Over the years wet cell, vented lead acid batteries have been giving way to sealed, recombinant-gas lead acid batteries. The latter type has the advantage of not requiring to be opened. Sealed lead acid batteries also have a higher energy density than the flooded lead acid devices, according to Concorde. The company supports more than 30 airframe manufacturers, including Piper, Cessna, Diamond, Dassault, and Gulfstream, Koss says. It has more than 100 battery models for use in more than 200 aircraft, according to the company.

Lead Acid Battery Test and Maintenance

Maintaining sealed lead acid batteries is pretty straightforward. You don’t open them, but you do have to check them for airworthiness. “It’s like a tire – you can have a fully charged tire that is worn out,” Koss says. With a new sealed lead acid battery, “you have to check the capacity of the battery at least annually to verify the storage ability for essential power.” Subsequent checks could be as frequent as every three months, depending on factors such as the battery, its percent of capacity, the aircraft, and the usage profile. After a capacity test is completed, the battery should be immediately recharged. A lead acid battery, however, should never be discharged to zero during testing because of the risk of damaging the unit, warns test equipment maker, JFM Engineering. JFM’s test equipment can be used with NiCad or lead acid batteries.

VDC Electronics and COFKO Electronics are among the companies providing test equipment for lead acid batteries. VDC’s BatteryMINDer line of products can be used with either SLA or wet cell batteries. These products can trickle-charge batteries to maintain capacity when the aircraft are not being used.

The Wright Brothers

Feb 24, 2016

by Joy Finnegan, Editor in Chief

I read a lot and most books, while I enjoy them, don’t capture my imagination or inspire awe about the subject. Every once in a while I read a book that just blows me away. I recently read such a book. It was “The Wright Brothers” by David McCullough.

I was riveted from the first page. I thought I knew a lot about these two men, Wilbur and Orville Wright, who changed our world. I mean I have been in the business all my professional life, I am an aviation history buff, have taken classes on aviation history and read numerous books about aviation history. I have visited Kitty Hawk multiple times and stood at the rails where the first flight of the Wrights took place. But I learned so much more about them, and their genius, that I had to write about this book and recommend it to anyone. Here are some of the interesting things I learned.

Wilbur became obsessed with the idea of conquering the challenge of manned, powered flight and began to read all the available documented research on the subject. The Smithsonian provided numerous books and research including the work of Louis Pierre Mouillard, who had studied the aerodynamics of birds, a method the brothers also used before building their first flyer. Wilbur also looked intently at the work done previously by Otto Lilienthal and Octave Chanute and other experts of the day. Chanute, a somewhat older, wiser contemporary, became an adviser of sorts. Initially the brothers took all the previous research as gospel.

The next remarkable thing was the idea of safety that permeated all the brothers did. As they determined that a place with steady strong wind was required for their experiments and found Kitty Hawk on the Outer Banks of North Carolina, they began building their first flying machine and transported it there in pieces.

Remember that many had died in hasty, poorly researched attempts to fly. But Wilbur wrote this while at Kitty Hawk preparing for their attempt, “The man who wishes to keep at the problem long enough to really learn anything positively must not take dangerous risks. Carelessness and overconfidence are usually more dangerous than deliberately accepted risks.” He knew that to solve the problem would require a steep learning curve. To climb that curve, the brothers would need to live through their attempts. Therefore, they determined to stay low to the ground and found the soft sand of Kitty Hawk the perfect emergency landing surface.

The next point about these two brothers that hit home hard for me was that even among the rugged, hard working men and women of the remote and harsh North Carolina coast, the Wrights were greatly admired for their work ethic. One of the locals who helped and observed them over many days said they were “’two of the workingest boys’ ever seen ‘and when they worked, they worked. They had their whole heart and soul in what they were doing,’” according to McCullough’s book.