Featured Research

from universities, journals, and other organizations

New Research Helps Protect Airplane Engines From Drizzle

Date:
November 1, 2004
Source:
National Center For Atmospheric Research
Summary:
Heavy freezing drizzle--appearing to be harmless light drizzle--has cost airlines as much as $2 million in engine damage in a single storm as jets have waited for takeoff. Now Roy Rasmussen of the National Center for Atmospheric Research (NCAR) has developed a new system to identify the drizzle accurately. His research has enabled airlines to revise pilot training and on-ground procedures to avoid future damage.

Heavy freezing drizzle iced up this jet engine as the pilot waited for takeoff. The white swirl is a design feature.
Credit: Photo courtesy United Airlines.

BOULDER - Halloween weather has tricked, not treated, airport meteorologists the past two years in Denver. Heavy freezing drizzle--appearing to be harmless light drizzle--has cost airlines as much as $2 million in engine damage in a single storm as jets have waited for takeoff. Now Roy Rasmussen of the National Center for Atmospheric Research (NCAR) has developed a new system to identify the drizzle accurately. His research has enabled airlines to revise pilot training and on-ground procedures to avoid future damage. The new detection system will be installed this winter at Denver International Airport (DIA).

Rasmussen studied two cases of heavy freezing drizzle at DIA on October 31, 2002, and the same date in 2003. The two storms wreaked a total of $2.85 million in damage to 18 jet engines on United Airlines 737 aircraft. Trained meteorologists were on site throughout both events, but the freezing drizzle conditions were not accurately noted. In about half of all cases of freezing drizzle, the intensity is underreported, according to Rasmussen.

"Freezing drizzle is hard to see and its intensity is hard to estimate visually," says Rasmussen. "Often it goes undetected because the droplets are so small." The typical droplet diameter is about half of a millimeter, or half the thickness of a compact disk.

Rasmussen has worked with United Airlines to alert pilots of 737 aircraft on the hazard, and the airline has changed its procedures as a result of his research. Formerly, if an airport meteorologist observed heavy freezing drizzle, engines were revved close to flying speed (called an engine run-up) every 30 minutes to throw off ice.

"Now, if anyone says 'freezing drizzle,' they do engine run-ups every ten minutes," says Rasmussen. "Airline people are sensitized to the possibility that freezing drizzle can cause engine damage."

The real-time freezing-drizzle detection system developed by Rasmussen and colleagues will be part of Weather Support for Decision Making (WSDM), a system now at DIA that offers minute-by-minute weather reports tailored to aviation users. WSDM data are displayed in a color-coded, user-friendly format that can be easily read by pilots and other non-meteorologists. WSDM also provides data on snow and unfrozen rain.

Freezing rain falls right past an idling jet engine, Rasmussen explains, but freezing drizzle falls at a much slower rate, so it gets sucked into the engine. The droplets freeze on contact, and the resulting ice builds up on the engine's hub, or spinner. When the engine is revved up to takeoff speed, ice shards are thrown off the spinner into the rest of the engine.

In the two Denver storms, the major damage was to the delicate tips of the fan blades. These blades generate the lift that makes the plane fly, Rasmussen says. If they're damaged, the plane loses thrust, because the blades are not at the correct angle to produce the maximum thrust.

"It's not particularly dangerous," says Rasmussen, "but they have to repair the damage, and that's very costly."

###

The Federal Aviation Administration's Aviation Weather Research Program funded Rasmussen's research. NCAR's primary sponsor is the National Science Foundation.


Story Source:

The above story is based on materials provided by National Center For Atmospheric Research. Note: Materials may be edited for content and length.


Cite This Page:

National Center For Atmospheric Research. "New Research Helps Protect Airplane Engines From Drizzle." ScienceDaily. ScienceDaily, 1 November 2004. <www.sciencedaily.com/releases/2004/10/041030212814.htm>.
National Center For Atmospheric Research. (2004, November 1). New Research Helps Protect Airplane Engines From Drizzle. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2004/10/041030212814.htm
National Center For Atmospheric Research. "New Research Helps Protect Airplane Engines From Drizzle." ScienceDaily. www.sciencedaily.com/releases/2004/10/041030212814.htm (accessed April 17, 2014).

Share This



More Matter & Energy News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

German Researchers Crack Samsung's Fingerprint Scanner

German Researchers Crack Samsung's Fingerprint Scanner

Newsy (Apr. 16, 2014) German researchers have used a fake fingerprint made from glue to bypass the fingerprint security system on Samsung's new Galaxy S5 smartphone. Video provided by Newsy
Powered by NewsLook.com
Porsche CEO Says Supercar Is Not Dead: Cue the Spyder 918

Porsche CEO Says Supercar Is Not Dead: Cue the Spyder 918

TheStreet (Apr. 16, 2014) The Porsche Spyder 918 proves that, in an automotive world obsessed with fuel efficiency, the supercar is not dead. Porsche North America CEO Detlev von Platen attributes the brand's consistent sales growth -- 21% in 2013 -- with an investment in new technology and expanded performance dynamics. The hybrid Spyder 918 has 887 horsepower and 944 lb-ft of torque, but it can run 18 miles on just an electric charge. The $845,000 vehicle is not a consumer-targeted vehicle but a brand statement. Video provided by TheStreet
Powered by NewsLook.com
Industry's Optimism Shines At New York Auto Show

Industry's Optimism Shines At New York Auto Show

Newsy (Apr. 16, 2014) After seeing auto sales grow last month, there's plenty for the industry to celebrate as it rolls out its newest designs. Video provided by Newsy
Powered by NewsLook.com
Ford Mustang Fetes Its 50th Atop Empire State Building

Ford Mustang Fetes Its 50th Atop Empire State Building

AFP (Apr. 16, 2014) Ford celebrated the 50th birthday of its beloved Mustang by displaying a new model of the convertible on top of the Empire State Building in New York. Duration: 00:28 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins