Altitude

In the beginning, it gave hope to older men trying to give their sexual performance a lift. Now sildenafil, better known by its trade name, Viagra, is gaining popularity for a different use among skiers and mountain climbers. Their concern: avoiding high-altitude pulmonary edema, a potentially deadly condition in which excess fluid collects in the lungs. Research has been accumulating about sildenafil's value in nonsex-related uses. The drug has been shown to help some people with high blood pressure in arteries supplying the lungs, a condition known as pulmonary hypertension.

Question: Two years ago, I traveled to Tibet, including Lhasa at 11,975 feet above sea level. I started having mild headaches. Two weeks later, as the plane was landing in San Francisco, I became non-responsive. I underwent a craniotomy to relieve pressure from a clot next to my brain. I've had other altitude issues, including passing out while snowshoeing near Mammoth and experiencing altitude sickness after leaving Cuzco, Peru. I know commercial flights are pressurized above sea level, and I have taken some domestic flights.

Georgia Jones-Davis' review of Sheila Nickerson's "Disappearance: A Map" (Book Review, Feb. 4) caught my eye and upon reading it, I noted a number of misstatements. Given the topic, I believe the last two words of the book's subtitle should read "High Latitudes," not "High Altitudes." Most of what is being discussed happens at or near sea level, and if not, then generally within the first 10,000 feet of the Earth's atmosphere--not what could be called "high altitude" by any stretch of the imagination.

Where is the John Muir of the San Gabriel Mountains? The Ansel Adams of the San Bernardinos? The Donner Party of the San Jacintos? All right, maybe one Donner Party was enough. But Muir, Adams and company are among the reasons the inland mountains of Southern California have never quite matched the attention won by their taller northern neighbors, the Sierra Nevada. Still, hikers, board-riders, skiers and snowball-tossers in Southern California find no shortage of peace and exhilaration.

A few weeks ago, Javier Aguirre was in Arlington, Texas, swapping football memories with Jerry Jones, the owner of the Dallas Cowboys. That's football, not futbol . It turns out that the coach of Mexico's national soccer team is not only an NFL fan but a Cowboys fan. And not only a Cowboys fan but a Roger Staubach fan. "I have to confess, I've been a Cowboys fan since birth," Aguirre told Jones. "I have everything when it comes to Roger Staubach. Everything." Jones had stopped by his new House of Many Splendors -- the $1.15-billion Cowboys Stadium -- to watch Mexico's soccer team train for a Gold Cup quarterfinal game against Haiti.

One minute and 15 seconds before its disastrous midair collision with a single-engine Piper Cherokee Archer over Cerritos on Sunday, Aeromexico Flight 498 was advised by an air traffic controller of another airplane nearby. "Traffic at 10 o'clock, one mile, northbound, altitude unknown," the controller radioed.

Acute mountain sickness affects people at high altitudes. Symptoms include dizziness, confusion and fatigue. In her 15th novel, "A Change in Altitude," Anita Shreve writes about it knowledgeably. Perhaps she was suffering from it as she wrote, because this novel is a mess. Shreve can be an excellent writer. It's easy to understand why her work appears on bestseller lists. Usually her prose is clear, her descriptions elegant and her plot twists surprising and original, enticing us to keep turning pages.

In what may well be one of the last aviation firsts, a University of Toronto graduate student has fulfilled an ancient dream that dates back at least to the Greek legend of Daedalus and Icarus — human-powered flight. In an ungainly wing-flapping craft, or ornithopter, built by students at the university, Todd Reichert made history last month by sustaining both altitude and airspeed for 19.3 seconds, traveling a little more than 145 yards at an average speed of about 16 mph. The flight, conducted at sunrise Aug. 2 at the Great Lakes Gliding Club in Tottenham, Ontario, was witnessed by a vice president of the Federation Aeronautique Internationale, which certifies aviation records.

Teetering 23 miles above the New Mexico desert, Felix Baumgartner plans to leap head first into the abyss and become the first free-falling human to break the sound barrier as he plummets to the ground. The feat, which will put his life on the line and push his body to the limit, is scheduled to take place shortly after dawn Monday when he falls from 120,000 feet in the air. JUMP DELAYED: The attempt by Felix Baumgartner to set the world's free-fall record at 23 miles has been postponed from Monday to Tuesday because of a cold front with gusty winds near Roswell, N.M. Wearing a newly designed pressurized suit and helmet, the Austria native will test the threshold of his equipment as scientists, aerospace engineers, the Air Force and NASA study what it shows about the limits and capabilities of the human body bailing out from aircraft at ultra-high altitudes.

Regarding the suggestion that it can be helpful to use higher-octane fuel at higher altitude ("Before Taking a Motor Trip, Check Your Cash Efficiency," Travel Insider, May 19): This makes no sense. Gasoline burns slower at higher altitude because of less oxygen, which effectively boosts octane. You will find that the octane ratings on all grades of gasoline sold in high altitude areas of the country are lower. RAY ELIAS Los Angeles Christopher Reynolds replies: Mr. Elias is right about lower octane levels being necessary at higher altitudes.

Teetering 23 miles above the New Mexico desert, Felix Baumgartner plans to leap head first into the abyss and become the first free-falling human to break the sound barrier as he plummets to the ground. The feat, which will put his life on the line and push his body to the limit, is scheduled to take place shortly after dawn Monday when he falls from 120,000 feet in the air. JUMP DELAYED: The attempt by Felix Baumgartner to set the world's free-fall record at 23 miles has been postponed from Monday to Tuesday because of a cold front with gusty winds near Roswell, N.M. Wearing a newly designed pressurized suit and helmet, the Austria native will test the threshold of his equipment as scientists, aerospace engineers, the Air Force and NASA study what it shows about the limits and capabilities of the human body bailing out from aircraft at ultra-high altitudes.

RAWALPINDI, Pakistan - Icy wind whipped Lt. Nauman Ahmed's face as he plodded up a barren expanse of snowfields and crevasses. Woozy and spent, he reached a Pakistani military outpost 20,000 feet above sea level and slumped down on a cot in one of the camp's fiberglass igloos. The next morning, the peril of waging war in the world's highest conflict zone began to take its toll. His head throbbed, and he was coughing up blood. When he tried to speak, he couldn't form words. "I thought to myself, 'What is happening to me?

Left for dead near the summit of Mt. Everest, Australian adventurer Lincoln Hall survived the night alone, without supplies, in temperatures well below zero. And then he got lucky. As dawn broke, one of the last teams of climbers to ascend the mountain in 2006 encountered Hall sitting cross-legged near a ledge with a precipitous drop. His first words were, "I imagine you are surprised to see me here. " The team abandoned its own summit attempt to rescue Hall, whose wife and two sons had already been told he was dead.

Reporting from Mammoth Lakes -- Meb Keflezighi has been to the mountaintop. And he liked it so much he decided to buy a house there. That was 11 years, three daughters, one American record and an Olympic medal ago. Now Keflezighi is as comfortable at high altitude as the Abominable Snowman — and that, he says, is what made a lot of those other things possible. "We had a vision to be able to change U.S. distance running by coming here," says Keflezighi, the Olympic trials marathon champion and a medal hopeful at this summer's Games in London.

Saying they are concerned about the safety of spectators, federal officials have refused to approve a controversial airplane race that was promoted as one of the main attractions at this weekend's Camarillo air show. Instead of watching high-performance propeller planes weave through inflated pylons at an altitude of 15 feet, the expected crowd of 40,000 will have to settle for a more modest aerial display. The decision by the Federal Aviation Administration prohibits the Ultimate Air Race Championship from staging a high-speed competition that has been advertised as "Faster than NASCAR" and a showcase for seven of the world's best pilots.

Retired Col. Arthur "Kit" Murray, an experimental test pilot who set an altitude record in 1954 when he piloted a Bell X-1A at 90,000 feet at nearly twice the speed of sound, has died. He was 92. Murray died July 25 of complications from Alzheimer's disease at a nursing home in West, Texas, his family announced. A decorated pilot during World War II, Murray received the Distinguished Flying Cross for saving the X-1A rocket plane — stabilizing and safely landing it — after it tumbled out of control for 22,000 feet from the record height over what is now NASA Dryden Flight Research Center.

The article on the high Andes trek ("Altitude Adjustment," Dec. 13) described difficulties on the trek in a way that could not be further from the truth. I have taken hundreds of people on treks in the Peruvian Andes, and I have yet to see somebody suffering [with the altitude] in such a way. The acclimatization upon arrival prepares you and makes the trekking adventure in these remote mountains a wonderful experience. DEVY REINSTEIN Andes Adventures Santa Monica

A single-engine plane crashed in the desert outside of Indio on Monday, killing the pilot. Pilot James Wesley Hanbury, 30, of Banning was involved in cargo-dropping experiments for the military, when the crash occurred north of Bermuda Dunes, the Riverside County Sheriff's Department said. Investigators said the Cessna 150 lost altitude when a parachute carrying one of the cargo packages got tangled in the tail of the aircraft.

Angelenos have long complained about the noise of helicopters hovering over Southern California neighborhoods — and one politician is hoping he can finally ensure some peace and quiet. Rep. Howard L. Berman (D-Valley Village) introduced legislation Thursday targeting noise from low-flying helicopters above Los Angeles County's residential neighborhoods. Berman's Los Angeles Residential Helicopter Noise Relief Act would require the Federal Aviation Administration to establish rules on flight paths and minimum altitudes for helicopter operations in those areas within a year of the bill's being signed into law. Exemptions would be allowed for emergency responders and the military.

C-17 Globemaster III cargo plane Built by Boeing in Long Beach First flight: 1991 Price: About $240 million Number delivered: 226 Wingspan: 169 feet 10 inches Length: 174 feet Height: 55 feet, 1 inch Cargo compartment: 88 feet long, 18 feet wide and 12 feet, 4 inches high Speed: 515 mph Cruising altitude: 45,000 feet Customers: U.S. Air Force, Britain, United...