The Importance Of Being Grounded

Lightning strike during thunderstorm - being grounded
Image Source – Lightning strike during thunderstorm  

The importance of being grounded has recently been highlighted by Transport Canada and the FAA. The latest Feedback for Canadian Aviation Service Difficulty Reports, highlighted the importance of correct assembly of electrical terminals. An occurrence of a melted wire on the starter connector of aircraft APU resulted.

This last month the FAA also issued an AD ordering Boeing to fix some newly manufactured 737 electrical bonding issues.

The importance of proper grounding and bonding cannot be overstated. That said, one of the more common maintenance errors that are discovered when inspecting aircraft wiring is the improper assembly of bonding and grounding points.

Bonding and grounding requirements are; to ensure that an adequate low resistance return path for electric, avionic, communication and electronic equipment is achieved. This can withstand operating conditions and corrosion. This is essential for the reduction of coupling of electromagnetic fields into or out of the equipment. Additionally, for providing electrical stability to control the currents and/or voltages caused by static charges and discharges and for suppressing the hazardous effects thereof.

SAE document ARP1870 provides for detailed information on grounding, bonding and the application of related hardware, primarily for system design. AC43-13 Chapter 11 Section 15 provides similar general information for the AME, aircraft manufacturers standard practices provide airframe specific instructions.

Some of the more common mistakes are lack of preparation of the mating surfaces, terminals installed on top of lock nuts, missing lock washers, too many terminals on a single stud.

Correct assembly of ground stud

Correct assembly of ground stud
Image from SAE International AEROSPACE RECOMMENDED PRACTICE Manual ARP1870

These errors may not be immediately apparent as all systems can appear to be working correctly. The deleterious effects result in inflight fires and critical system failures. More commonly, intermittent glitches in electronic equipment. These can take tens of thousands on dollars and hundreds on manhours to track down.

The bottom line is to be aware of the airframes standard practices. For aftermarket approvals and equipment manufacturers installation manuals, refer to AC43-13 as directed. Do it right first time and prevent future problems.


What’s Your Poison – Glass Cockpit or Round Dials?

Glass cockpits have been around for decades, replacing the original round dials, first in transport category aircraft and then filtering down to the smallest general aviation and experimental aircraft.

Are glass cockpits for everyone? Traditionalists will maintain that using round dials is essential to obtain and maintain the excellent stick and rudder skills real flying demands, but glass cockpits are now a fact of life. Some new pilots may never have flown with round instruments.

Has this advanced technology improved safety or the flying experience? I had one sales rep for a major avionics manufacturer, in a moment of unguarded candour, describe his company’s product as “just eye candy”.

But glass cockpits do have many advantages over round dials some of which are listed below:


  1. No parallax. The next time you are pre-flighting an airplane, try to read round dial instruments from the right seat. In glass cockpit equipped aircraft, the viewing angle still makes a right-seater’s job difficult, but there is no parallax.
  • Accuracy – With a glass cockpit, you are not interpreting altimeter or airspeed needle position, the numbers are displayed on the screen.
  • Graphical weather display – The ability to have near real time data linked weather displayed in the cockpit provides pilots with forecasts, radar reports, satellite imagery, pilot reports, and more.
Image of Graphic Weather Display
Graphic Weather Display
  • Traffic display – In congested airspace, traffic display will never replace keeping the pilot’s eyes outside the aircraft but it can be an invaluable aid.
  • Terrain awareness and synthetic vision – Plays an important role in increasing situational awareness.
  • Check Lists – You always have checklists at your fingertips no more searching the cockpit for the paper copy.
  • Airspace Mapping – It’s sometimes hard to judge where airspace boundaries start and end. Glass cockpits show position compared to airspace boundaries.
  • Eye Candy – They do look great and can give passengers a sense of confidence in the aircraft.
  • Reliability – With fewer parts, no spinning gyros, etc. there is less to go wrong.
  • Bluetooth Syncing – The ability to transfer flight plans from an IPad directly to the avionics system.

It is a truism, however that no aircraft is ever safer than the pilot flying, and the accident data does not show glass cockpits to be inherently safer than round dials.

As the biggest impediment to the adoption of glass cockpits is cost, if you are looking for improved flying safety it may be better to invest in your personal flying skills and hours flown than in more technology.

The pros and cons of glass are a great debate to have. The technology is constantly evolving but it will be many years, if ever that glass becomes a must for every pilot or mission.

ADS-B What is all the talk about diversity?

Unlike the FAA in the United States, which over the last two decades invested in ADS-B ground stations to cover the majority of their landmass. Nav Canada invested in Aireon, a space-based ADS-B solution to cope with our vast and sometimes inaccessible geography.

Space-based ADS-B
Space-based ADS-B

This has resulted in most of the general aviation fleet having their transponder antennas on the wrong side of the aircraft, bottom verse top. So, do we just need to relocate the antenna?

It’s not that simple for several reasons. ADS-B ground stations are still located at many Canadian airports, requiring the bottom antenna to be retained. For anyone flying into US airspace only having a top-mounted antenna would not work with a ground-based system. To deal with these issues, transponders need to be diversity models.

Diversity in ADS-B

Diversity in ADS-B refers to having two antennae connected to a single transponder.

The way a single transponder system is connected to two antenna functions is through a technique called Diversity. Each antenna is connected to a dedicated receiver in the transponder. When the system is interrogated, the signal strength measured in each receiver is compared to the other and the one with the strongest signal directs the single transmitter to reply through its antenna only. The requirement for two separate receivers and the comparator circuitry is what increases the cost of diversity transponders by several thousand dollars.

ADS-B transponders are also mandated to continually broadcast the aircraft position and information regardless of interrogation. Diversity transponders alternate their broadcast between the two antennas the Aireon satellite system does not interrogate; it relies on this unsolicited ADS-B Out broadcast.

When can we expect implementation?

Unlike the United States all-or-nothing ADS-B Out equipage deadline on January 1, 2020, Nav Canada is planning a phased implementation. As to when – due to pressure from pilots and operators about the cost of diversity, Nav Canada has delayed implementation and is working with Transport Canada to finalize mandates. Stay tuned for updates.


Why do today what you can put off until tomorrow  

With the current pandemic and the associated restrictions hopefully easing soon, this is definitely the time for aircraft owners and operators to ensure their aircraft are properly equipped. Here is what you need to know about ADS-B.

ADS-B out is now a requirement to fly in most US airspace and will, in the not-too-distant future, be required in Canada.

With Transport Canada and Nav Canada still to finalize an equipage mandate, aircraft owners who wish to fly to the USA have been left in a quandary. Do they equip for US airspace and risk having to replace a new transponder if it does not meet Canadian requirements? Or, equip to meet the most stringent requirements and risk overspending?

There are ways to mitigate this dilemma. First, UAT transponders, the cheapest of equipage in the USA will not meet any Canadian mandate. So unless you only use your aircraft to fly from uncontrolled Canadian airspace across the border this is a non-starter.

An ADS-B 1060Mhz transponder will meet the US and Canadian requirements, but there is a catch. The US system is ground based, the Canadian system is space based.

If the Canadian mandate requires an antenna on the top of the aircraft to communicate with satellites then a transponder with antenna diversity will be required. This can increase the cost of the installation considerably.

When making a decision to install an ADS-B transponder in the current regulatory uncertainty it would be prudent to install a unit that is upgradeable for antenna diversity in the future.

Some like the L3 Lynx, just require the top mounted antenna and the purchase of an unlock code to enable diversity. Others will require a trip back to the factory and some will require replacing.

Example of Lynx ADS-B Transponder with traffic display
Lynx ADS-B Transponder with traffic display

If you are spending to meet the mandate, then should you not get something out of it? ADS-B in, is it worth it? Obviously that’s a decision every owner has to make, but once you’ve flown with ADS-B traffic displayed in congested airspace you’ll never fly without it.

Contact us for competitive quotes and to schedule your installation.

Missing NBAA, Oshkosh, Heli-Expo or other Flagship Industry Trade Shows

Missing flagship industry trade shows this year? Like NBAA, Oshkosh, Heli-Expo or other flagship industry trade shows. Is this a concern, a non-event, a mixed blessing?

Attending industry conference and walking the exhibition floors of trade shows is one of the best ways to keep updated on what’s going on in our industry. There is always a company with a new product or service that has not been well marketed but has great potential to our operations and businesses.

Some companies are exhibiting futuristic designs for where they envision the industry is headed. Some are destined to fail, others destined for market dominance.

Face to face meetings with suppliers and clients, along with networking with other aviation professionals can be invaluable. Add in the social aspects, as an attendee it’s usually a worthwhile event and a great perk for company employees.

RMA Team 2019 at NBAA trade show
RMA Team at NBAA 2019

For exhibiters however trade shows may be expensive, disruptive and hard to quantify in value. Some exhibitors I have spoken with at these events confess that the only reason they still attend is the fear that if they don’t their clients may see it as a sign of financial difficulty. Others have quipped that the only people who benefit from these events are the organizers and the local nightlife.

With virtual conferences now being the only events for the foreseeable future, seminars and training classes have moved online. For the tradeshow portion of these events, can exhibitors create engaging digital experiences that will overcome “Zoom fatigue”? If they do, can anything really replace the tactile experience of a live event?

No one can see into the future with certainty, but many will speculate, what does the future hold for the trade show industry? The pandemic – or at least governments reaction to it – has forced people to change their behaviors.

We’re primarily social animals, and we’ve been locked down, prevented from doing business as usual and prevented from socializing or having normal face to face interactions for many months now. With various vaccines now proving their efficacy, in twelve months we could be back to pre-pandemic behaviour.

Will trade shows come roaring back? If a company has spent hundreds of thousands on a virtual trade show presence, will they be willing to abandon the investment and return to the status quo? Will there be a blend of virtual and on-site?

Just a prediction, cabin fever is a powerful emotion, book early for 2022.

Digital Autopilot for Twin Otter Aircraft

Digital autopilot for Twin Otter aircraft is here. After several months working with Genesys (S-TEC) to gain approval for a new digital three axis autopilot, final flight testing was completed last month in Calgary, using one of Rocky Mountain Aircraft‘s Twin Otters.

The new system was put through its paces in all modes and aircraft configurations and performed flawlessly throughout the flight testing.

STEC 3100
STEC 3100 Installation

The FAA issued the STC SA09761DS on October 06, 2020.

With a list price of just under $25,000 for a full three axis autopilot, the 3100 is cheaper that the two axis limited functionality System 65 autopilot it replaces.

All the components are on condition only, eliminating the costly and time-consuming overhaul of servos that blighted the OEM Collins autopilots installation.

Genesys S-TEC 3100 Digital Flight Control System

The Details

The System is a digital three-axis attitude-based Digital Flight Control System (DFCS), and is designed for installation in aircraft equipped with a dual or single Air Data and Attitude Heading Reference System (ADAHRS), and/or DFCS computer internal sensors.

The System provides roll, pitch and (Optional) yaw modes along with an integral autotrim feature. The autopilot  includes a straight and level recovery feature, as well as envelope protection/alerting features.

The Programmer/Computer provides a means to engage the autopilot, select modes of system operation and to annunciate system modes and status. The Programmer/Computer consists of two sections: roll and pitch. The roll section accepts steering inputs from the navigation radios and the ADAHRS or internal sensors and uses this information to drive the Roll Servo. The pitch section receives signal inputs from the Primary Flight Displays and ADAHRS or internal sensors, and uses this information to drive the Pitch Servo. Yaw axis stabilization is provided by drive commands to a remote mounted Yaw Servo.

The Elevator Trim is automatically controlled by the Trim Servo, which also provides trim annunciation.

Twin Otter Ingenuity and Adaptability

In these unsettling times, we have found that focusing on ingenuity and adaptability has kept us strong and positive.  Regardless of what is happening, we are maintaining our high standards of quality and are appreciating the depth of knowledge in our staff, and the resources that we can rely on.

It turns out that innovation and ingenuity have not been stymied as a result of the pandemic. Developments that were underway have been brought to completion and can now be shared.  See our Emergency Roof Escape Hatch

Adaptability is evidenced in our response to supply chain and logistical challenges, while new Service Bulletin (SB) requirements on top of Covid-19 operational requirements have been met with in-house solutions and resources.  See our Exchange Flight Controls

It may be difficult to be optimistic given the very real challenges faced by our industry, but a “glass half full” look at uncertain times can see opportunities for increased versatility, profitability and reliability in operations.  See our Avionics upgrades

DHC-6 Taking Flight
Twin Otter Taking Flight

Twin Otter Emergency Roof Escape Hatch

For Twin Otter operators who because of regulatory requirement, or operational needs, still have the OEM Viking cabin roof escape hatch. Are you experiencing problems with fitment, delamination or other unserviceability?  Have you had no option but to continuously carry out time consuming repairs as the hatch is no longer available?

Cabin Roof Escape Hatch

Rocky Mountain Aircraft have recently received TCCA STC approval for a replacement cabin roof escape hatch. The replacement hatch is manufactured from aluminum sheet unlike the OEM balsa core material, so is immune from delamination.

The replacement part RMA-C6FS2413-11 along with the STC are in stock and ready to ship.

AOG for Twin Otter flight controls?

Did you know? Rocky Mountain Aircraft keeps most Twin Otter Flight controls in stock ready for exchange, purchase or as loaners if we are repairing yours.

Viking SERVICE BULLETIN V6/0066 for Aileron Structure Inspection requires borescope inspection equipment that many operators don’t possess and those that do may discover significant repairs required. Minimise aircraft downtime with an economical exchange from Rocky Mountain Aircrafts stock.

Flight Controls
Flight Controls

Spending a fortune on analog instrument repair and gyro overhauls?

The old electro-mechanical instrumentation that has served the Twin Otter fleet well for over fifty years has reached the end of their economical life. Attempting to coax a few more years of service out of these systems is only going to cause heartache and expense. It’s time to invest it reliability and modernity.

Modern avionics systems will increase profitability, versatility and reliability. Isn’t it time your cockpit looked like this?

Avionics Cockpit
Avionics Cockpit

Don’t Just Kick the Tires and Clean the Windscreen

As air travel and aviation in general start to take the first tentative steps to emerge from the Covid-19 lockdown, the reactivation of aircraft that have been parked for the past three of four months needs to be addressed.

Storing aircraft, even for the short-term is nothing new for most major airlines. However, for smaller regional airlines, corporate flight departments, and other commercial operators this may have been a new experience.

So were the aircraft properly stored and were measures taken to safeguard the aircraft’s ultra-sensitive avionics systems? All apertures and openings through which environmental factors – sand, dirt, water, birds, and insects – can find their way inside an aircraft are wrapped up and made watertight. That includes engines and air data probes – such as pitot, static, temperature, angle of attack sensors – engine intakes and exhausts, and APU intakes and exhausts.

Were maintenance or maintenance control staff furloughed? Have calendar-based inspections lapsed? Are the CVR/FDR, ELT, Altimeters, Transponders overdue recertification?

Emirates Airlines estimates that It may require around 4-5 dedicated employees and at least 18-24 hours to put just one of its aircraft back into service.

With the aircraft now ready to fly, what about the aircrew? Recency will have expired for most aircrew unless they had access to a simulator, proficiency checks will be overdue for some.

Start-up procedures will have to be carefully managed to ensure that public confidence in air travel, already at historic low because of the pandemic, is not further compromised.

At Rocky Mountain Aircraft we have some unique expertise at reactivating aircraft from years of improper storage or even abandonment. With our own aircraft back online we are happy to offer advice and assistance to enable our industry to soar back into the skys.

Time to reactivate - Sleeping Plane

Is Age a Factor in Aircraft Safety?

Boeings new 737 MAX have been grounded for over 12 months following two crashes and multiple loss of lives. The 737 MAX airliner only entered airline service in 2018.

Recently, the Snowbirds lost one of their aircraft, the cause is currently unknown but public speculation has focused on the age of the aircraft. The Tutors CT-114 jets first flew in 1960.

The answer to the question “Is age a factor in aircraft safety?” of course should be an emphatic no. The regulated design, maintenance and operation of an aircraft is in place to ensure that an aircraft is as safe to fly from the day it leaves the production facility to the day it is finally withdrawn from service.

What keeps an aircraft safe, is its robust safety systems to manage Design, Operation, and Continued Airworthiness. These need to be embedded into every organization that is involved in aviation, and audited by independent regulators. Jurisdictions that limit the age of aircraft are making a tacit admission that their systems and oversight are lacking.

One result of the 737 Max accidents was in design procedure failures for new aircraft types as has been highlighted. From the information released by the initial investigation, regulatory oversight had been compromised. A secure non-punitive reporting system at Boeing had failed, a toxic corporate culture had developed, and commercial pressure had resulted in an unsafe aircraft design being allowed into airline service.

The DC3 an example of aging aircraft
Kenn Borek Air DC3 Basler
Photo Credit – Alex Praglowski

While the 737 Max is grounded, the venerable DC3 designed and first flown in the 1930s is still in use with some specialist operators. Commercial air travel is still the safest form of transportation, but when accidents do occur it is normally due to complex multifaceted failures of safety systems. No accident investigation has ever come to the conclusion that the aircraft was “just too old to fly anymore”

Twin Otter Autopilots

It may appear that Twin Otters and autopilots don’t mix. That would be the conclusion you would come to looking at a survey of the number of Twin Otters with an installed autopilot. So what is the history and why do operators shun autopilots in the Twin Otter?

The first production aircraft left the Downsview factory with an option for the Honeywell H-14 autopilot. This system used large pneumatic servos to control the aircraft. This was a popular option at the time however as the aircraft and autopilot aged the maintenance involved in keeping the system serviceable resulted in many operators disabling or removing the system. Other approved autopilot options followed, the Bendix M4-C, Collins APC-106 both these systems while having dispensed with the pneumatic systems and being fully electric still required regular scheduled maintenance to keep them airworthy, the regular overhaul of the servo’s being particularly onerous.

The last autopilot system introduced by DeHavilland was the Collins APS-65. Introduced in 1989 the APS-65 was one of the last analog autopilots designed prior to the shift to digital. This highly capable autopilot had one main drawback, it was hugely expensive and thus not a popular upgrade or option.

For operators requiring an autopilot, a retrofit autopilot was introduced by S-TEC, the System 65, this is a basic two-axis autopilot a lot less capable than the APS-65 but at a fraction of the cost. The System 65 has become the “go-to” autopilot for operators who need an autopilot since it was first certified in the
Twin Otter 25 years ago.

New state-of-the-art retrofit autopilots are being certified in many different airframes at an incredible rate.

Manufactures like Avidyne, Garmin and Genesys (S-TEC) are regularly expanding their approved model lists. The capabilities of the new digital autopilots compared to their 50 year old predecessors is vast, modern autopilot do much more than keeping an aircraft on a preset heading and altitude. They can almost fly the aircraft independently from take-off to landing. That capability should not be taken lightly. A pilot must still be completely aware of exactly what it is the autopilot system is or isn’t doing.

So why are these maintenance free, inexpensive, multi-function, safety enhancing autopilots still missing from Twin Otters?

It appears we have a chicken and egg situation here, no autopilot manufacturer is investing in a Twin Otter approval because there is no perceived demand among operators, but there is no demand because there are no systems available.

So who will break this impasse, which manufacturer will be the first to follow the “if you build it they will come” philosophy?

Well, the answer is Genesys Flight Systems who will be certifying their 3100 digital autopilots on one of Rocky Mountain Aircraft’s Twin Otters. Installation and approval are expected by the summer of 2020. A full review of the installed system, its performance and capabilities will be posted on this blog. Stay tuned.