NASA Studies Source of Ice Crystals in High Places


NASA’s DC-8 airborne laboratory is inspected and secured for the night at Cecil Field in Jacksonville, Florida. NASA’s High Ice Water Content research activity spent July 2022 flying through thunderstorms investigating ice crystal formation and how they affect the performance of aircraft engines.
Credits: NASA / John Gould

A team of NASA researchers are once again using NASA’s DC-8 airborne laboratory to study ice crystals – and more – within the heart of large thunderstorms in a bid to improve jet engine designs and increase flight safety.

The work is part of NASA’s High Ice Water Content (HIWC) research activity, which has previously conducted two flight research campaigns: the first out of Florida in 2015, and the second out of Florida, California, and Hawaii in 2018.

Now, the team is back at it again, conducting a flight campaign during July off the southeast coasts of the United States and the Gulf of Mexico.

This time, the team – which includes Federal Aviation Administration (FAA) and Japanese partners – is using Cecil Airport in Jacksonville, Florida, as their base of operations.

“For this campaign we’re doing something a little different. Our priority is to conduct flights in regions with human-made aerosols to better understand what effect they have on the development of high concentrations of ice crystals,” said Thomas Ratvasky, HIWC’s principal investigator from NASA’s Glenn Research Center in Cleveland.

These tube-shaped instruments on the tip of the DC-8’s wing are used by NASA’s High Ice Water Content research activity to gather data on ice crystals.
These tube-shaped instruments on the tip of the DC-8’s wing are used by NASA’s High Ice Water Content research activity to gather data on ice crystals. The isokinetic probe (left) measures total water content in clouds. The other device is a cloud droplet probe that measures smaller cloud particles.
Credits: NASA / John Gould

Aerosols 101

Aerosols are tiny particles in the atmosphere that result from a variety of both naturally occurring and human-made sources. Burning of fossil fuels, industrial emissions, and agricultural activity are just a few examples.

These pollutant aerosols, once released into the air, move through the atmosphere, and eventually can be carried out over the ocean.

Once they interact with convective systems, one theory suggests they can increase the concentrations of ice crystals present in a thunderstorm – although exactly how this complex interaction works is generally unknown.

In these storms, specifically mesoscale convective systems, high concentrations of ice crystals form. When an aircraft flies through them, its jet engines’ power and performance can decrease.

That’s why HIWC researchers have been gathering data on ice crystals, their prevalence, and their effect on jet engines.

With this additional flight campaign attempting to study aerosols, HIWC is bridging a gap in the existing data that regulatory bodies will use to consider new safety standards for mitigating ice crystals.

“We want to make sure that high-aerosol environments are represented in this dataset. Many of today’s engines were not required to demonstrate capability in flying in these ice crystal conditions, but future ones will,” Ratvasky said.

Don’t Cool Your Jets

During the past 30 years, there have been more than 170 reported incidents of power loss and engine damage in commercial transport jets such as airliners when flying through convective systems.

Here’s how it happens: jets fly through an area with a high concentration of ice crystals. Some of the ice crystals enter the core of the engine – where its power is generated.

In some conditions, the ice crystals form a layer of slushy water inside critical components such as the compressor. The transfer of heat from the engine into the icy slush causes ice to build up in the compressor. When this ice sheds, engine power loss or damage may occur.

Elsewhere on the aircraft, instruments collecting important information for pilots, such as the aircraft’s speed, also can be obstructed by ice crystals, leading to erroneous and inaccurate readings in the cockpit.

To learn the role aerosols play in the development of high concentrations of ice crystals affecting an aircraft’s performance, HIWC is utilizing NASA’s DC-8 aircraft, based out of NASA’s Armstrong Flight Research Center in California, and flying through storms with a high amount of both ice crystals and aerosols.

An air-inlet tube sticks out of a modified window aboard NASA’s DC-8 airborne science laboratory.
An air-inlet tube sticks out of a modified window aboard NASA’s DC-8 airborne science laboratory. As it flies, air enters the tube and is guided inside the aircraft, where instrumentation detects how many aerosols are present in the atmosphere. The work is part of NASA’s High Ice Water Content research activity.
Credits: NASA / John Gould

Flying Laboratory

The HIWC team has souped-up NASA’s DC-8 with their data-gathering instruments and other technology, allowing onboard researchers to study the environment in real-time.

On the DC-8’s left wing and nose are devices to measure the total water content of the clouds the aircraft flies through, as well as a probe to measure smaller cloud-sized droplets.

Meanwhile, the right wing is home to particle instruments capable of measuring the size and shape of the larger ice particles.

Inside the nose is a modified weather radar, used in collaboration with researchers at NASA’s Langley Research Center in Virginia, to detect storm conditions up ahead of the DC-8’s flight path.

A new instrument added to the aircraft for this flight campaign is the Passive Cavity Aerosol Spectrometer probe. This canister-like device measures the number of aerosols in the air.

Nagoya University in Japan owns and operates this and other aerosol instruments and is collaborating with HIWC in the research.

On the aircraft’s starboard side is an inlet that directs air into the aircraft itself, where it flows through a series of instruments before being exhausted out of the aircraft further downstream.

Inside the DC-8 are racks of monitors, displays, and other stations where researchers sit and view the data as they fly.

Each flight lasts approximately seven hours, and thousands of miles are flown at a variety of speeds and altitudes.

In a typical flight profile, the team flies at the same higher altitudes as airliners to fly through ice crystals. Then, they descend to very low altitudes – even below 1,000 feet – to hunt down aerosols before they have risen into the storm and interacted with cloud and ice crystals.

Rest assured; safety is paramount. The aircraft is in the hands of experts who know what to expect and how to deal with ice crystals.

“We’re not flying anywhere different than an airliner would fly so we can get data that is applicable to normal operations. Our pilots and the entire team are aware of the hazards to engine and air data system performance caused by HIWC and we utilize procedures to minimize those hazards,” said Ratvasky.

A look inside NASA’s DC-8 aircraft.
A look inside NASA’s DC-8 aircraft, facing forward. High Ice Water Content researchers sit at these consoles and operate equipment that gathers data on the outside conditions they are flying through. The aircraft’s flight deck can be seen in the background.
Credits: NASA / John Gould

High Flying Partnerships

Close cooperation among several organizations who contributed both expertise and project funding make HIWC’s work possible.

“We could not do this without all the collaboration both internal and external to NASA. We have the science group from Langley, the icing group from Glenn, and the airplane from Armstrong. The FAA is supporting instrumentation, and Nagoya University and the Japan Meteorological Agency have provided their expertise and aerosol instrumentation,” said Ratvasky.

Following the flight campaign, the next step is to process the data then pass it on to the FAA and other bodies such as the Ice Crystal Icing Aviation Rulemaking Advisory Committee.

Once studied, the relatively new standards for jet engine certification will be assessed and could all but eliminate power loss incidents due to ice crystals in convective systems.

John Gould
Aeronautics Research Mission Directorate

Last Updated: Jul 29, 2022

Editor: Lillian Gipson

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D Boss
July 31, 2022 4:58 am

Ohh, Ahh. pencil pushing pin heads are studying how aerosols impact ice crystal formation! But wait, duhhhh – aircraft of any type or size are normally not flown into known convective activity. Pilots avoid CB’s like they are carrying the plague. (CB= CumulonimBus)

Furthermore, mankind’s aerosol production is entirely dwarfed by what nature routinely does:

For the past almost 2 weeks, and continuing an humongous Saharan Dust cloud is impinging on the Atlantic, Caribean, and Gulf of Mexico, with Florida in the mix. It is estimated to contain 180 million tonnes of dust: (As of June 6, 2022, the plume stretched from Africa to South America and even reached Puerto Rico. All told, it covered more than 2.2 million square miles (5.7 million square kilometers) of the tropical Atlantic Ocean.)

That one dissipated, and now there is another one as large or larger.

So smart guys at NASA, how is it this aerosol cloud made by nature, supresses convection, reduces water content and does not promote ice crystal formation (because there are almost no thunderstorms)? But you contend man made aerosols increase ice crystal formation in thunderstorms? Or did you just tack on the “man made” aspect to secure funding by ticking the green nutbar subscriber check box?

Peta of Newark
Reply to  D Boss
July 31, 2022 5:26 am

Yet strangely, in other parts of climate science, dust particles create clouds and rain.

Epic rant btw, somebody who knows their own mind and, contrary to how it will be ‘taken’ by the pin-heads, NOT out of their mind
I luvz it

Again: Everything in this world is now wrong.

D Boss
Reply to  Peta of Newark
August 1, 2022 4:05 am

Thanks, but it’s an epic rant due to actual knowledge and experience with flying and understanding the extreme danger of CB’s or any convective activity. I am a pilot.

Reply to  D Boss
July 31, 2022 8:22 am

You would rather they just use models to study how weather works?

D Boss
Reply to  MarkW
August 1, 2022 4:09 am

We and they already know how this aspect works. What I disagree with is saying or insinuating that man made aerosols are the drivers of ice formation in CB’s Essentially without aerosols or condensation nuclei there would be no rain, let alone ice crystals – so stop making natural necessary features of the real world into some man made monster!

Reply to  D Boss
July 31, 2022 12:28 pm

D Boss,
 Pilots avoid CB’s like they are carrying the plague. (CB= CumulonimBus)”
Probably doesn’t give enough emphasis, based on my Father’s hatred of them. He was shot down – French Anti-Aircraft, he thought – over Dunkirk in 1940, but managed 4,400 hours flying before his Golden Bowler..
Didn’t talk all that much [to me] about his service, but I gathered that ‘plague crossed with rabies’ – with a side of anthrax – would be closer to his dislike of Cb.
From sea level – my vantage point – Cb is magnificent, and can be useful if you’ve just had a passel of shitehawks perched on your foc’stle, and need a deck wash. But radars on.


D Boss
Reply to  auto
August 1, 2022 4:13 am

Aye mate. Cleaning the foc’astle and fertilizing plants by releasing nitrogen are some of the benefits of CB’s on the ground level. Not to mention they are the air conditioners for the planet as many posit on this site.

I like your addition to the pilot’s view of CB’s – plague crossed with rabies with a side of anthrax – that about sums up how a towering cumulonimbus is viewed by sane pilots!

Tom Abbott
July 31, 2022 5:00 am

I would think their results would be applicable to explaining a little better how the weather works.

July 31, 2022 5:43 am

Passive Cavity…


What’s the footprint of a 7 hour flight?

Zig Zag Wanderer
Reply to  fretslider
July 31, 2022 6:57 am

3 Al Gores (my new metric)

Clyde Spencer
Reply to  Zig Zag Wanderer
July 31, 2022 7:58 am

I thought that was a measure of volume, not length.

Reply to  Clyde Spencer
July 31, 2022 8:30 am

Volume of hot air actually.

And when expelled, this is known to give some people the vapours.

Right-Handed Shark
Reply to  Clyde Spencer
July 31, 2022 9:59 am

Density. An AlGore is a unit of density, equivalent to 1Gigathunberg.

Old Man Winter
Reply to  fretslider
July 31, 2022 8:14 am

Since NASA is part of the gubmint bureaucracy, they probably snatch up any
“extra airframes” that were part of the military’s order, which may be how
they got this DC-8. They then load it up with sensors to collect data they &
other users want. If they were a private research company, they’d probably
be using modified drones equipped with sensors that would relay data to
ground stations. It’s much cheaper, safer, cleaner & takes less time but
NASA is stuck in the bureaucratic framework where “Das ist verboten!

This DC-8 pictured probably has the same turbofan engines used to
upgrade the KC-135 refueling tanker, which itself had problems caused
by flights through rain and hail that were eventually resolved. The original
turbojet engine pictured below left a cloud of smoke upon take off, like the F-4.

July 31, 2022 6:38 am

170 incidents in thirty years?
In 2019 there were over forty million airline flights plus many additional cargo jet and private jet flights.

william Johnston
Reply to  tommyboy
July 31, 2022 7:38 am

I guess one can’t be too careful.

Clyde Spencer
Reply to  tommyboy
July 31, 2022 8:00 am

Statistically insignificant — unless you or a loved one happens to be on one of those 170 flights. Relativity rules the universe.

Reply to  tommyboy
July 31, 2022 10:23 am

Air France 447 crash over the Atlantic (1992) was a high-visible incident of the hazards of inadvertent convection penetration with icing protection (pitot tube anti-ice) turned off. The Air Florida 90 crash into the Potomac River in Washington DC (1982) was another example of failure to use engine anti-icing protection. Aircraft already have protection against these icing situations…they just have to be used.

Rich Lambert
July 31, 2022 6:46 am

Aircraft are not designed to fly through thunderstorms. NASA should reconsider if the data is actually needed and use alternative methods to collect this data if needed.

Reply to  Rich Lambert
July 31, 2022 7:34 am

The DC8 would be better employed flying Nancy to Taiwan.

Clyde Spencer
Reply to  toorightmate
July 31, 2022 8:01 am

How about a Slow Boat to China?

Bob Hoye
Reply to  toorightmate
July 31, 2022 8:06 am

One-way and leave her in Beijing.

Sweet Old Bob
July 31, 2022 6:47 am

“Burning of fossil fuels, industrial emissions, and agricultural activity are just a few examples.These pollutant aerosols, ” ….

Gotta stop the plebs from eating ,traveling etc …

Old Man Winter
July 31, 2022 7:02 am

Unlike all the other “garbage research” that is actually nothing more than
staying in the office & designing more useless models, these folks are
actually collecting REAL WORLD data that they can do REAL analysis on
that hopefully can be used to improve weather forecasting & flight safety,
two REAL WORLD needs. While they have the usual Green spiel, it’s still much, much better than all of NASA’s wasted time & $$$ spent on social justice programs!

July 31, 2022 7:33 am

Deliberately fling any aircraft into an electrical storm is abso-bloody-lutely ridiculous.
These are the stark raving idiots who are trying to place our younger generation into continuous states of fear.

Old Man Winter
Reply to  toorightmate
July 31, 2022 8:54 am

Unlike the phony baloney Fear Porn™ The Team™ feeds our youngsters,
real lightning can zap you 25 miles from the thunderstorm.

Clyde Spencer
July 31, 2022 7:56 am

This, unlike climate, falls withing NASA’s purview as described in its original charter. It has not been given proper attention because of mission creep into more profitable research.

Reply to  Clyde Spencer
July 31, 2022 8:35 am

profitable research or propaganda research?

July 31, 2022 9:39 am

Just by weather watching you get clues about whats going on in the upper air.
Yesterday afternoon here in England l saw a ‘mock sun’, these turn up more often during the winter months. As it needs very cold air for them to form. So this one turning up yesterday told me that the upper air above England must have been very cold for the time of year.

July 31, 2022 3:54 pm

I have no idea whether this study is practical or useful but when I read this,

“With this additional flight campaign attempting to study aerosols, HIWC is bridging a gap in the existing data that regulatory bodies will use to consider new safety standards for mitigating ice crystals.”

I got suspicious and less interested.

Dr. Jimmy Vigo
July 31, 2022 5:16 pm

Oh wow, I wasn’t finished reading when I spotted this one: it says there that

“aerosols are tiny particles in the atmosphere that result from a variety of both naturally occurring and human-made sources. Aerosols can increase the concentrations of ice crystals present in a thunderstorm, although exactly how this complex interaction works is generally unknown”.

Well, now I feel stupid here, because this is NASA high end flying research lab saying this, but we chemists know from precipitation principles that particles are excellent promoters of crystallization because they act as seeds. The surface area attracts by Van ser Walls forces the molecules of the chemical to be crystallized. We do this on purpose in organic chemistry when you want to make powder of a drug; you can add a bit of previously-crystallized amount to what we call the mother liquor of the new crystals to form. We chemists grow complex structures of drugs in solid state at different pH values, and organometallic complexes of heavy metals, which work as semi and superconductors.

I don’t get how highly-technological NASA doesn’t have clear the chemical logical argument that atmospheric water crystals are seeded by aerosols, is that a mystery to them?? This is easy to prove! Take samples of the crystals and do chemical analyses with stuff like HPLC/GC-MS, IR, Uv/Vis spectroscopy, NMR, X-ray crystallography; detect aerosol chemicals in crystals of water. That’s standard analytic chemistry.

I’m going to read the rest, trying to see something clearer about this “mystery”. If the chemistry proves right, they should be already making statistical analysis of how much water crystallization is caused by human aerosols versus how much by nature; add to that a study based on altitude too.

Isn’t that kind of thinking standard in NASA??
I’m just an almost unemployed chemist.

JBVigo, PhD

July 31, 2022 5:55 pm

This icing condition only occurs where water vapor accumulates on warmer surfaces within the engine nacelle then migrates to where it isn’t wanted. Drainage is problematic as the drain paths keep freezing too. From these studies we learn that this condition, firstly is an issue, and subsequently how to avoid it.

Lower altitude icing conditions are also more common and dangerous. Ice buildup is quite damaging to lift as it collects on wings and flight controls, both reducing lift and adding weight.

July 31, 2022 6:10 pm

Sorry guys they are testing at much higher altitudes than most Cb’s go. Cb’s usually top out around 30k ft (9500 m) but can go higher. They are looking at high and dry (relatively) ice clouds at above 1000 m (35f ft) typical of airliner cruising altitudes.
Real design surprisingly needs real data.

July 31, 2022 11:57 pm

Humm … based on history (e.g. weather studies in the ’50’s being U-2 spy flights), this seems like it could be a cover for a different “secret” venture. Not saying that it is, but …

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