CH-53E Readiness Crisis and Mid Air Collision Catastrophe
A US Marine Corp (USMC) investigation charts a readiness crisis in the Sikorsky CH-53E Super Stallion fleet, that resulted in a dip in proficiency and spike in fatigue at a squadron based in Hawaii, that triggered the dramatic relieving the Squadron CO of command and a fatal mid air collision (MAC) that killed 12 marines just days later.
Two CH-53Es (161255 and 163061) of HMH-463 squadron based at MCAS Kaneohe Bay collided during a night training sortie on 14 January 2016, 2 miles off the coast of Ohau, HI. “Low light conditions made it difficult for the aircrew to recognize the rapid decrease in separation between the aircraft which led to the collision,” said Lt. Col. Curtis Hill, a spokesman for the USMC. However as the Marine Times notes:
….the underlying causes of the crash reveal the squadron suffered from severe readiness problems like flight hours and parts shortfalls that are endemic to Marine Corps aviation — especially the troubled CH-53E fleet.
The squadron did not have enough helicopters that could fly; crews were not getting enough flying hours; morale was low and crews were battling fatigue…
Without enough flyable aircraft, the squadron was about 606 hours behind on its scheduled flight hours for fiscal 2016 by January, the investigation says. Pilots feared the low number of working aircraft was causing their skills to atrophy.
According to the investigation, the four pilots had logged 4, 5, 4, and 13 hours of flight time in the 30 days before the accident, all less than the USMC’s 15.1 hour monthly goal for the CH-53E. The investigation also concluded that two of the pilots were not “adequately proficient” in using night vision devices.
We look further at the circumstances leading to this accident.
The Overall Fleet Airworthiness Situation
The heavily redacted USMC report explains that:
A 2015 study noted that readiness within the Marine Corps’ CH-53E fleet was “appalling” due to inadequate inventory; too many aircraft in maintenance; lack of designated resources; no fleet-wide “reset” following operations Iraqi Freedom and Enduring Freedom; insufficient maintenance training, oversight, equipment, formal and on-the-job training, and technical support.
In 2008, the Marine Corps implemented the Integrated Maintenance Concept program. For several years preceding 2008, the number of fully mission capable CH-53Es hovered around 50%. From 2008 to 2015, the number of fully mission capable CH-53Es steadily declined from approximately 50% to 20%.
The CH-53E fleet has the highest cannibalization rate in the USMC rotary fleet.
From 2012 to 2015, the number of Out of Reporting aircraft (i.e. in long term maintenance] increased by 78% fleet-wide.
In FY2015 only 44 of the USMC’s 146 CH-53Es were classed as mission ready on average.
…a fleet-wide “reset” is currently underway. The reset…involves validation and verification of all CH-53E aircraft, training for maintenance Marines, modification of the supply system to make it more agile, and other changes intended to address the erosion of maintenance skills.
In February 2016 The Virginian Pilot reported:
“I’m not happy at all where we are with the (Super Stallion) right now, but I do believe we have a recovery strategy that will work,” said Lt. Gen. Jon M. Davis, the Marine Corps deputy commandant for aviation, in an interview with The Pilot. “I’m proud of what we’re doing to fix this, but I’m not proud of where we’re at right now. The taxpayers should be unhappy.”
Davis ordered the Super Stallion review a year ago, part of a broader effort to improve combat readiness after more than a decade of fighting. Similar studies have been conducted or are ongoing for other Marine Corps aircraft, including the MV-22 Osprey and AV-8B Harrier.
Many of the Super Stallion’s problems can be traced to the decision not to do a full reset after years of fighting in Afghanistan, Davis said.
“We were trying to get maximum readiness at the time, and the best way to do that was to do it in theater (in Afghanistan),” Davis said. “Frankly, we needed to do what the Army did. That would have given us less aircraft to fly then, but we’d have more aircraft to fly now. … We made a mistake. But now we’re recovering from that.”
The Super Stallion’s problems are a symptom of a systemic issue plaguing the military, said Todd Harrison, director of budget analysis at the Center for Strategic and International Studies in Washington. Delays and cost overruns for new weapons systems – including the CH-53K, which initially was expected to begin replacing the Super Stallion last year but won’t be ready until at least 2019 – are putting a strain on the upkeep of existing assets, Harrison said.
Since 2013 the CH-53E accident rate has been 79 per million flying hours, four times higher than the historic fleet average. Accident rates were also rising across the USMC. Issues had already been flagged with US Navy MH-53Es after a 2014 accident after wiring chaffing fuel pipes.
The Squadron Airworthiness / Readiness Crisis
The following chart plots HMH-463’s mission ready aircraft (‘RBA’ – yellow line) and total flight hours (‘FHE’ – green line) together with key events top in black from January 2014 to March 2016. Also shown is the total assigned aircraft (‘ASN’ – black line), long-term maintenance ‘Out of Reporting’ aircraft (‘OOR’ – blue line) and the In-Reporting fleet (‘IR’ – red line) which is the assigned fleet minus the long term maintenance aircraft. The aircraft in short term maintenance or otherwise not mission ready is the difference between red and yellow lines. From 2013 to January 2016, the number of mission ready HMH-463 CH-53Es peaked at 6 but was generally around 2.
Marine Rotational Force-Darwin (MRF-D) is a force made of various Marine Corps troops and assets, including aircraft that deploy to and conducts training and exercises in Darwin, Australia for approximately 6 months each year.
In January 2015, Airframes Bulletin 345 was released, which required the inspection and potential replacement of aircraft ramp bushings. The senior leadership of HMH-463 described this as a significant burden to HMH-463 maintenance which was preoccupied with preparing aircraft for MRF-D 2015.
In July 2015, Airframes Bulletin 346 was released, which required the inspection and potential replacement of fuel lines. This also added a significant burden to HMH-463 maintenance department at a time when the Marines were executing scheduled phase inspections.
On 4 September 2016 the results of a a maintenance inspection by the 1st Marine Air Wing were released. HMH-463 failed the inspection. In reality:
In the summer through fall period of 2015, HMH-463 was effectively a three-site maintenance department: supporting MRF-D with a four aircraft detachment in Darwin, Australia; supporting the fall [Weapons & Tactics Instructor] WTI class in Yuma, Arizona; and attempting to fly at home station in Hawaii. The HMH-463 Marines believed this reality made maintenance coordination a challenge.
Flight operations ceased for over a month while HMH-463 focused on fixing the problems.
Due to the poor readiness the unit’s personnel were ordered to go to 12 hours on 12 hours off shift pattern.
Most members of HMH-463 did not see any end in sight with regard to the long working hours. They claim this led to low morale and cumulative fatigue throughout HMH-463.
Fatigue offers one of the greatest potentials for crew error at night.
On 11 January 2016 the squadron commander was relieved of his post “because of a loss of confidence stemming primarily from inadequate improvement in HMH-463 aircraft readiness rates from the time of the failed inspection in September 2015 through the first days of 2016”.
The interim acting CO told the squadron they were not “shut down” and it was to be “business as usual.” On 14 January 2016 a new CO was appointed.
The former squadron CO claims he told the Brigadier General that took this action that:
…his relief for readiness was a dangerous precedent to set. He said, “If the General wants up aircraft, the Marines will get him up aircraft,” implying that readiness reporting would become inflated and corrupted.
The Brigadier General did not recall that.
Brigadier General Sanborn brought HMH-463 together and said, “I just relieved your CO.” He then told each HMH-463 member to look into the mirror and ask “yourself if you were a positive, negative, or neutral force in the squadron” and whether their action or inaction helped lead to the CO’s relief.
Brigadier General Sanborn did not provide guidance on whether to continue business as usual or to cease flight operations through an operational pause.
At 1700, a briefing was held, attended by most HMH-463 Marines. During the address it was stated there were “going to be some changes.” Some Marines believed this mean that more HMH-463 leaders were to be relived of from duty.
A two ship night flight was planned for the 14 January 2016. The previous day the unit Aviation Safety Officer (ASO) had had a “heated discussion” ad he was concerned over the mitigation of risk for this sortie. A Risk Assessment Worksheet was completed for the sortie but appears to have ignored the risk due to low proficiency, fatigue and other organisation issues. Witnesses suggest that briefings were given by personnel who appeared tired and distracted. Mission planning documents featured multiple errors.
During this sortie, while formation flying at night, the two aircraft collided.
Other commentators have highlighted: Reduce Flying Hours at Your Peril: Increased Accident Rates in the USN and USMC
The decline in USN and USMC non-deployed flying rates are a cause for concern, as demonstrated by increased home station accident rates. Fixing the problem will take time.
Reporting indicates that these crashes are part of a sharp increase in military aviation accidents overall for non-deployed squadrons, which have absorbed the bulk of budget cuts through reduced training and delayed maintenance at home so the best aircraft and personnel can be used on deployment overseas.
Across the board, the number of Navy and Marine aircraft lost in accidents has doubled during the first 11 months of fiscal year 2016 compared to the same time in 2015. Twenty aircraft had been destroyed as of 29 August, compared to 10 aircraft during the same time in 2015, according to Naval Safety Centre data.
According to data from the Naval Safety Centre, the overall number of flight hours for the Marines and Navy has been relatively steady over the past few years. However, deployed operations have taken up an increasing share of those flight hours over home training operations, which means non-deployed pilots are not flying very much.
UPDATE 20 November 2016: We report on a fast jet Military Airprox in Sweden
UPDATE 30 November 2016: House and Senate negotiators have finalised a $618.7 billion defense policy bill for 2017 that increases funding for military readiness and higher troop levels at the expense of proposed plus-ups for fighter aircraft procurement.
UPDATE 28 December 2016: Aviation crisis continues: Marine fighter squadron commander fired
Lt. Col. Wade Workman was relieved of his duties Wednesday as head of Marine Fighter Attack Squadron 232, which has seen two of its F/A-18 Hornets crash since Workman took command on Jan. 15, said Capt. Kurt Stahl, a spokesman for the 3rd Marine Aircraft Wing. “The decision to relieve Lt. Col. Workman was unrelated to recent mishaps,” Stahl said in an email. “This decision was based on issues concerning command climate within the squadron.”
Maj. Gen. Mark Wise, commander of the 3rd Marine Aircraft Wing, decided to fire Workman due to a ” loss of trust and confidence” in his ability to serve as squadron commander, Stahl said. “There was an unhealthy command climate that negatively impacted trust within the unit that is critical to effective operations,” Stahl said.
Workman is the fourth commander in the aviation community to be fired in 2016.
On Dec. 5, Wise relieved Lt. Col. Michael E. Hernandez as commander of Marine Aviation Logistics Squadron 11. Wise’s decision to fire Hernandez was based on performance; “No misconduct was involved,” a 3rd Marine Aircraft Wing news release said.
In April, Lt. Col. Armando Gonzalez was fired as commander of Marine Wing Support Squadron 371 in Yuma, Arizona, after a command investigation found he “created an intimidating, hostile, and offensive work environment.”
And in January, Lt. Col. Edward Pavelka was relieved of command of Marine Heavy Helicopter Squadron 463 just three days before two of the squadron’s CH-53E Super Stallion helicopters collided off Hawaii, killing 12 Marines. An investigation found that the squadron did not have enough flyable helicopters, crews were not getting enough flying hours and morale was low prior to the crash.
It is not clear what systemic actions have been taken.
UPDATE 1 February 2017: “Without more money from Congress, the Marine Corps will have to stop flying aircraft this summer, the head of Marine aviation said”.
UPDATE 4 February 2017: The BBC say “Death crash US jet pilot ‘did not report issues’” to maintenance.
UPDATE 6 February 2017: Grounded: Nearly two-thirds of US Navy’s strike fighters can’t fly
In 2017, Congress failed for the ninth straight year to produce a budget before the October 1 start of the fiscal year, reverting to continuing resolutions (CRs) that keep money flowing at prior year levels. CRs have numerous caveats, however, and many new projects or plans can’t be funded since they didn’t exist in the prior year.
There is widespread agreement that CR funding creates havoc throughout the Pentagon and the industrial base that supports it – often substantially driving costs higher to recover from lengthy delays. Yet, like the proverbial weather that everyone talks about but no one can change, there seems to be little urgency in Congress to return to a more business-like budget profile.
According to the Navy, 53 percent of all Navy aircraft can’t fly – about 1,700 combat aircraft, patrol and transport planes and helicopters. Not all are due to budget problems – at any given time, about one-fourth to one-third of aircraft are out of service for regular maintenance. But the 53 percent figure represents about twice the historic norm.
The strike fighter situation is even more acute, and more remarkable since the aircraft are vitally important to projecting the fleet’s combat power. Sixty-two percent of F/A-18s are out of service, 27 percent in major depot work and 35 percent simply awaiting maintenance or parts, the Navy said.
With training and flying hour funds cut, the Navy’s air crews are struggling to maintain even minimum flying requirements, the senior Navy source said. Retention is becoming a problem, too. In 2013, seventeen percent of flying officers declined department head tours after being selected. The percentage grew to 29 percent in 2016.
UPDATE 8 February 2017: More than half of all Marine aircraft unflyable in December
Out of 1,065 Marine Corps aircraft, 439 were flyable as of Dec. 31, said Lt. Gen. Jon Davis, deputy commandant for aviation. That represents roughly 41 percent of the service’s fixed- and rotary-wing aircraft.
“My target should be 589 [flyable aircraft]; so I am 150 airplanes shy of what I need to make my flight-hour goal.”
“November and December every year are low productivity months,” said Davis, who noted that 473 Marine aircraft were flyable at the beginning of October.
“I can only reset a CH-53E so fast. I’ve got seven on the East Coast; eight on the West Coast and one in Hawaii — 16 airplanes in reset right now. I can only get so many of those into reset at any given time.”
UPDATE 16 February 2017: Lack of maintainers is fueling the Corps’ aviation crisis
Some of the Marine Corps’ most experienced maintainers were allowed to take early retirement when the service shrank from 202,000 to 184,000 Marines, said Lt. Gen. Jon Davis, deputy commandant for aviation.
“We let some people go that probably – if we had better insight into who we had out there and the qualifications of those Marines inside the maintenance departments of our flying units – you’d say: ‘These people can’t go,’” Davis told reporters on Feb. 8.
“We will not grow the size of the Marine maintenance department. But we will grow the requirement to have additional qualifications inside that maintenance department,” Davis said at a Feb. 1 Defense Writers Group breakfast.
Davis acknowledged that maintainers are already extremely busy, but he believes they can be more effective… That’s why he wants corporals, sergeants and staff sergeants to spend more time on the flightline mentoring lance corporals on how best to take care of aircraft.
The Navy Times ran a story on 1 October 2016: Naval aviation trying to fix flawed safety culture: 1-star
…all too often these squadron leaders weren’t fixing safety issues over the last three decades, according to the leader of the organization charged with investigating Navy and Marine Corps mishaps, who said some commanding officers stashed the surveys rather than fix the problems. The Navy only got serious about fixing this flawed culture two years ago, he said.
“It was an organization basically frozen in time for about 30 years,” Rear Adm. Chris Murray said Sept. 10, referring to the state of things when he took over the Naval Safety Center in 2014. “Great at investigating things, but not doing a whole lot to prevent mishaps.”
“We’ve been doing surveys in squadrons forever,” Murray told the audience of aviators at the annual Tailhook reunion near Reno, Nevada. “Frankly, it was a great one-on-one with our guys and the squadron’s CO, but it never really got any further than that.”
The safety boss said the culture has been revamped so that these squadron surveys are get more scrutiny from higher ups and that officials are using more mishap data to assess the causes of mishaps.
UPDATE 25 September 2017: Marine Aviation Deaths Are Six Times Navy’s
UPDATE 25 January 2018: Commandant says the Marine Corps has ‘too many airplanes’
…the Corps is stuck with too many aircraft that it simply doesn’t have the time to fix or maintain…said Marine Commandant Gen. Robert B. Neller at a discussion Thursday at the Center for Strategic & International Studies in Washington.
“We need to get rid of them because we don’t have time to fix them.”
The Corps’ transition to new aircraft platforms like the MV-22 Osprey and the F-35B means other aircraft like the UH-1N, AH-1W, Harriers and Hornets have limited need or use.
Oddly Neller doesn’t mention the H-53 and claims “most of those accidents were not the result of major problems with the aircraft”:
Some were caused by poor decisions made by aircrews, some linked to lack of proper flight hours.
But, the Corps has made some slight progress over the last year, the commandant said. The average squadron recorded four more flight hours per aircrew than it did last year. The Marine Corps is still trying to get up to an average 16 flight hours per month, Neller said.
The goal for the Corps is to keep aircraft in the skies so that pilots can get the proper flight hours and training they need, Neller said. That requires a budget that removes uncertainty from the procurement process and the ability to get spare parts for aircraft.
“We need more airplanes that can fly,” he said. “We’ve got to turn parts faster.”
UPDATE 8 February 2018: Marine Aviation Going After Small Maintenance Issues that Create Big Readiness Problems
The biggest challenge squadrons of all type/model/series aircraft face is “not mission capable-supply,” where spare parts are not available and therefore the plane cannot be fixed and put back on the flight line.
Another counterproductive but prevalent action has been transferring aircraft between units, typically in an attempt to get the most modern and highest-capability airplanes to the squadrons about to deploy. …this can take about a thousand hours of maintenance per transfer, and within the V-22 fleet alone this has been done 650 times since 2011.
There is also an effort to minimise aircraft configuration differences that “slow down the maintainers and complicate the logistics chain”.
UPDATE 9 February 2018: Another observer notes: “…the Marine Corps’ aviation risk-management tools have become stale and lack the energy to stop mishap rates from rising. For example, the substance of CRM in the Navy and Marine Corps…has remained unchanged over decades.”
UPDATE 9 April 2018: US Navy’s spike in aviation mishaps is the military’s worst, up 82 percent
UPDATE 12 April 2018: Spike In US Military Accidents Linked To Poor Maintenance Planning
Rather than a lack of funding, [John Johns, former assistant undersecretary of defense for maintenance] believes the “overwhelming” amount of money allocated to the Pentagon through the Overseas Contingency Account (OCO) for combat operations has “made us a bit lazy,” he said April 10 at the annual MRO Americas conference
As a result, the military has abandoned basic maintenance strategies in the last 15 years that the U.S. has been engaged in the Middle East. Instead of long-term maintenance planning, the military has shifted to an “inspect and repair only as necessary” approach – using the “excuse” that operators need to turn assets around rapidly to get them back in the fight, Johns said.
UPDATE 15 April 2018: Pilot’s Failure to Deconflict Altitude Caused 2017 Weapons School Crash (2 USAF A-10s).
UPDATE 24 June 2018: The US Navy has recently raised concerns about the level of competence of their maintenance personnel after a series of maintenance related incidents.
The Navy has settled on a plan to double the length of some enlisted maintainers’ first shore tours, the Marine Corps has revamped its maintainer training and retention and aircraft towing policies…
They have also introduced an AMEX (Aviation Maintenance Experience Management) programme focused on qualifications and authorisation.
Meanwhile we look at: B1900D Emergency Landing: Maintenance Standards & Practices and offer suggestions of how to improve.
UPDATE 6 July 2018: Through multiple Freedom of Information requests, Military Times obtained data for every Class A through Class C aviation mishap that has occurred since fiscal year 2011.
UPDATE 31 July 2018: US Marine Chief Combat Developer: Aviation an ‘Inherently Dangerous Business’ Some VERY odd quotes that don’t reflect well on the Marine Corps.
UPDATE 11 August 2018: At least nine active duty US Marine Corps Aviation squadrons failed to accurately report the present state of their squadron’s aircraft readiness in late 2017 and early 2018 due to confusion about what data should be recorded.
UPDATE 31 August 2018: Retired Air Force Four-Star: How to Solve Aviation Crisis
…the best solution is for senior officials to keep the door open and have ongoing conversations on potential problems. “It’s not as much oversight as much as it is … going out and talking with [individuals] … just seeing what’s going on…”
UPDATE 10 September 2018: US Air Force releases findings of Operational Safety Review
The review pointed to several potential safety risks: Stress posed by high operations tempos; a lack of time to properly focus on flying basics; mission activities and training; the pressure to accept risk; cultural tendencies to always execute the mission; decreased aircraft availability; and the potential for complacency during routine tasks.
UPDATE 9 October 2018: The Navy’s Terrible Accident Record Is Now Hidden From Public View: The latest incidence of a government agency quietly removing data from its website demonstrates the dangers of an ever-changing internet.
UPDATE 11 December 2018: Unwinding the Maintainer Mess USAF has “fixed its maintainer shortage this year, closing a gap that had grown to 4,000—6 percent of requirements—as recently as two years ago”.
UPDATE 11 January 2019: Bad news for the CH-53E fleet which will have to carry on and fill the gap: USMC’s Huge New CH-53K King Stallion Helicopter Has Not So Tiny Problems, Faces More Delays
UPDATE 14 January 2019: All is not well in the USN surface fleet: Worse than you thought: inside the secret USS Fitzgerald probe the US Navy doesn’t want you to read
UPDATE 30 December 2019: ProPublica publish a scathing report on another USMC fatal MAC where they allege the official investigation focused blame within a squadron: Faulty Equipment, Lapsed Training, Repeated Warnings: How a Preventable Disaster Killed Six Marines: “Marine commanders did not act on dozens of pleas for additional manpower, machinery and time. When a training exercise ended in death, leadership blamed the very men they had neglected”.
Other Safety Resources
We highly recommend this case study: ‘Beyond SMS’ by Andy Evans (our founder) & John Parker in Flight Safety Foundation, AeroSafety World, May 2008, which discusses the importance of leadership in influencing culture. You may also be interested in these Aerossurance articles:
- How To Develop Your Organisation’s Safety Culture positive advice on the value of safety leadership and an aviation example of safety leadership development.
- How To Destroy Your Organisation’s Safety Culture a cautionary tale of how poor leadership and communications can undermine safety.
- Safety Intelligence & Safety Wisdom
- HROs and Safety Mindfulness
- Consultants & Culture: The Good, the Bad and the Ugly
As Aerossurance’s Andy Evans notes in this co-written article: Safety Performance Listening and Learning – AEROSPACE March 2017:
Organisations need to be confident that they are hearing all the safety concerns and observations of their workforce. They also need the assurance that their safety decisions are being actioned. The RAeS Human Factors Group: Engineering (HFG:E) set out to find out a way to check if organisations are truly listening and learning.
The result was a self-reflective approach to find ways to stimulate improvement.
Aerossurance has previously written the following:
- Gulfstream G-IV Take Off Accident & Human Factors
- Fatal G-IV Runway Excursion Accident in France – Lessons
- Culture + Non Compliance + Mechanical Failures = DC3 Accident
- Execuflight Hawker 700 N237WR Akron Accident: Casual Compliance
- Procedural Drift at Saab 340 Operator Leads to Taxiway Excursion
- ‘Procedural Drift’: Lynx CFIT in Afghanistan
- Loss of RAF Nimrod MR2 XV230 and the Haddon-Cave Review
- How To Develop Your Organisation’s Safety Culture
- Challenger Launch Decision – 30 Years On
- Chernobyl: 30 Years On – Lessons in Safety Culture
- Safety Intelligence & Safety Wisdom
- 10 Year Anniversary: Loss of RAF Nimrod MR2 XV230
- UPDATE 2 June 2017: Avoiding Mid Air Collisions: 5 Seconds to Impact
- UPDATE 2 July 2017: North Sea S-92A Helicopter Airprox Feb 2017
- UPDATE 30 August 2017: NTSB: Do We See and Avoid or Avoid Seeing?
- UPDATE 24 January 2018: RCAF Production Pressures Compromised Culture
- UPDATE 16 March 2018: USAF F-16C Crash: Engine Maintenance Error
- UPDATE 13 November 2018: Inadequate Maintenance, An Engine Failure and Mishandling: Crash of a USAF WC-130H
- UPDATE 17 November 2018: Investigation into F-22A Take Off Accident Highlights a Cultural Issue
- UPDATE 24 November 2018: AAIB Highlight Electronic Conspicuity and the Limitations of See and Avoid after MAC (Cessna 152 G-WACG and Guimbal Cabri G2 G-JAMM)
- UPDATE 18 December 2018: USAF Engine Shop in “Disarray” with a “Method of the Madness”: F-16CM Engine Fire
- UPDATE 27 December 2018: Inadequate Maintenance at a USAF Depot Featured in Fatal USMC KC-130T Accident
- UPDATE 30 December 2018: Fatal Biplane/Helicopter Mid Air Collision in Spain, 30 December 2017
- UPDATE 26 January 2019: MC-12W Loss of Control Orbiting Over Afghanistan: Lessons in Training and Urgent Operational Requirements
- UPDATE 16 February 2019: Merlin Night Airprox: Systemic Issues
- UPDATE 30 March 2019: Contaminated Oxygen on ‘Air Force One’ Poor standards at a Boeing maintenance facility resulted in contamination of two oxygen systems on a USAF Presidential VC-25 (B747).
- UPDATE 12 May 2019: Alaskan Mid Air Collision at Non-Tower Controlled Airfield
- UPDATE 14 August 2021: Alpine MAC ANSV Report: Ascending AS350B3 and Descending Jodel D.140E Collided Over Glacier
- UPDATE 2 May 2019: TSB Canada report on a Piper PA-42 Cheyenne III and a Cessna 150.
- UPDATE 20 May 2019: US Army C-27/USAF C-130 Night MAC 1 December 2014: The Investigation attributed the collision to a lack of visual scan by both crews, over reliance on TCAS and complacency despite the inherent risk associated with night, low-level, VFR operations using Night Vision Goggles.