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Monday, May 30, 2011

Grounded international flights may get back wings

Srinagar, May 27: If all goes as planned, international flights may again operate from the Srinagar ‘International’ Airport in next few months, brining respite to the stakeholders who have been pitching hard for revival of the service to bring Kashmir on the international air travel circuit.

       Highly placed sources disclosed to Greater Kashmir that serious efforts are on in the power corridors of New Delhi to revive the grounded Srinagar-Dubai flight and also make a Srinagar-Jeddah flight operational.

          The development comes in the wake of recurring demands from the stakeholders that the Srinagar-Dubai flight—which was launched with much fanfare by the United Progressive Alliance (UPA) chairperson Sonia Gandhi on February 14, 2009—be revived to give fillip to the tourism sector in Kashmir. The maiden international flight to Kashmir was grounded in January last year, with the Air India Express citing “it was not a commercially viable venture”—something which the stakeholders never accepted.

       “At appropriate levels, New Delhi has set in motion the process to revive the international flights and in the concerned quarters feasibility study is also being undertaken to look into the commercial viability of the ventures. Once the exercise is completed, you’ll certainly see some positive headway on the issue, which has been a long-pending demand of the people of Kashmir,” the sources disclosed.

        The Ministry of Civil Aviation, the sources said, is in the process of persuading the Air India Express, a subsidiary of Air India, on the issue. “So far there is nothing in black and white which says the Srinagar-Dubai flight was not a commercially viable venture. At least nothing of this sort has been communicated to the state government so far. There are, no doubt, some issues involved in the flight like a proper route plan, but those things can be sorted out,” they said. “It is in that connection, a feasibility study is must to sort out the issues facing the airlines and come up with a solution for the same. Having an airport with international tag serves no purpose. It has to be ensured that international flights operate from here so that the tourism sector in the Valley gets considerable fillip.”

THE DEMANDS
           The stakeholders have been crying hoarse to restore the Srinagar-Dubai flight and also the direct Hajj flights, which were not able to operate from the Srinagar ‘International’ Airport, last year. The tourism and travel agencies in Kashmir had reacted sharply to grounding of the flights, describing the international status of the airport as a “cruel joke being played with Kashmiris.” After the public outcry, the state Congress chief, Prof Saif-ud-Din Soz, raised the issue in the Parliament, urging the Civil Aviation Ministry to restore the service. “If you connect the flight with Jeddah, you will draw many customers,” Soz had told the Parliament in May last year.

      Sources said in the wake of criticism on the government’s failure to get the Srinagar-Dubai flight restored, the Chief Minister Omar Abdullah recently took up the issue with the Prime Minister Manmohan Singh.

‘WE ARE AT IT’
          When contacted, the Commissioner, State Civil Aviation Department, Capt S Katoch said the issue has been taken up at the highest level in the Centre.

         “And the state government is pursuing vigorously with the Government of India to recommence this operation, at least to the destination where it was working before and also to some other destinations. In a couple of months, we may see some decision in this direction,” Katoch told Greater Kashmir.

    “The GOI is very much aware of the problem. A couple of meetings have taken place on the issue and another meeting is scheduled next month where the matter shall again be discussed.”

‘FLYING RIGHTS ISSUE’
         Sources said route plans with regard to the international flights are also required to be reviewed. This comes in the backdrop of reports that foreign airlines are barred from carrying out operations from the Srinagar airport even though it has been designated as an “international airport.”

        “Foreign airlines cannot be allowed to operate direct flights from Srinagar as Pakistan does not allow these airlines to use its airspace (other than Indian) while flying to and from Srinagar. Foreign Airlines will have to follow a circuitous route, halting in either Delhi or Mumbai,” a Delhi-based newspaper reported last year when Srinagar was ousted as embarkation point for Hajj pilgrims.

         Sources said route permits need to be reviewed to see how best the flights can operate.

Competition for Atlanta flights to Bermuda ignites

Atlanta  flights  to Bermuda ignites                                                                
        That puts it in competition with Delta on the route.Atlanta flights to Bermuda push back from the gate at 10:25 a.m. and arrive on this almost mythical island at 2:25 p.m., in plenty of time to clear customs, check into your hotel and get ready for dinner. Return Bermuda flights do a quick turn and depart at 2:40 p.m., getting to the gate at Hartsfield-Jackson Atlanta International at 4:50 p.m. That puts you in position to connect to a slew of flights from AirTran’s largest hub.

  AirTran goes virtually head-to-head with archrival Delta, whose Atlanta flights to Bermuda depart at 10:55 a.m. and arrive at 2:45 p.m. Delta’s Bermuda flights to Atlanta push back at 3:45 p.m. and arrive ATL at 5:52 p.m.

       In either instance, with AirTran or Delta, connections at ATL go comparatively quickly. That’s because you clear customs in Bermuda, via pre-clearance. When you get off the plane in Atlanta, just go to your connecting gate.

     Bermuda is famous for pristine pink beaches, terrific tennis, and great restaurants. But the island is also rife with history – forts, gardens, historic houses, even a perfumery. A significant slice of Bermuda’s architectural history is tied to its houses of worship. The island has more churches per square kilometer than any place on earth.

Transpolar Flights : Good for the Planet, Bad for Your Health?

         Last month, I flew on a direct flight from DC's Dulles Airport to Beijing. About eight hours into the flight, I was surprised to learn that we were flying straight over the North Pole. From the window, I could see the vast stretches of ice floes and not much else. The plane was flying low enough that a man near the galley window took a photo with his iPhone that showed distinct snowy peaks. Passengers jokingly asked children whether they could see Santa Claus. It was eerily bright. Big cracks across the ice revealed canyon-like patches of open water. I had visions of what it must have been like when Ernest Shackleton got the Endurance stuck in the ice near the South Pole.
         As cool as it was to be flying over the top of the world, I had the distinct feeling that maybe this wasn't such a good idea. Some of my misgivings were for safety reasons: There aren't a whole lot of places to land out there should someone try smoking in the lavatory or if an engine falls off. But also, the North Pole looked, to my eye at least, like untouched wilderness. It's the last really unexplored place on earth, and it seemed like even the odd commercial jet could really disturb some critical if poorly understood ecological balance. But really, what did I know? I was just a random passenger.

          So when I got home, I decided to consult some experts to see what the possible environmental impacts might be, if any. What I learned is that transpolar flights have a lot of net benefits for the environment in terms of climate change. But those benefits have to be weighed against some fairly serious potential health issues for passengers—none of which were disclosed to us when I booked my ticket.

          In terms of environmental impact, those developments may be a good thing, because they shave significant amounts of flying time off trips from the US to Asia, saving hundreds of gallons of jet fuel and reducing the pollution produced by the jets. When Canadian officials were contemplating opening up the airways to more commercial jets over the North Pole in 2000, they estimated that the route would knock five hours off the usual flying time for a trip from New York to Hong Kong, for instance. That's serious money—and jet fuel.

          One of aviation's biggest contributions to climate change is the contrail, those clouds of condensed water vapor created by the jet exhaust. Because they trap outgoing radiation from the earth, the contrails are thought to contribute to global warming. I thought maybe some of this could be more pronounced at the North Pole, where holes in the ozone tend to show up, and where there are already myriad concerns that the ice is quickly melting from increased global temperatures. But David Fahey, a research physicist with NOAA's Earth System Research Laboratory who studies the upper atmosphere, says that he suspects that the arctic climate at the pole isn't very conducive to contrails, so that's probably not an issue. He posits that the Earth may be better off with more jets flying over the pole.

            People on those jets, however, might not be. One of the complications of flying over the North Pole is that planes and their passengers are exposed to significantly more radiation, especially during solar storms, than they would be on a traditional route. That's because the planes travel through the thinnest layer of the magnetosphere, which typically shields the earth and other commercial flights from cosmic radiation.

           When the transpolar flights were first considered in 2000, scientists estimated that flying over the North Pole would expose passengers to the amount of radiation they'd get in three chest X-rays, which could be hazardous to pregnant women. (Traditional routes would have exposure similar to less than two X-rays.) In 2009 NASA researchers discovered that during a 2003 solar storm, people flying over the North Pole would have been exposed to about 12 percent of the annual radiation limit recommended by experts, significantly more than regular commercial flights.

         Along with the radiation issues, flying over the North Pole presents some safety issues, in part because of the lack of places to land in an emergency (a concern when flying over the Pacific Ocean as well), but also because the magnetic forces and solar activity at the pole can really screw up navigation and communications systems. Planes making transpolar flights need special equipment to keep from getting lost—as the Korean Air flight 902 did when trying to make the polar route in 1978, prompting the Soviets to open fire and kill two passengers on the jet. There haven't been any major polar air disasters recently, but it's still something to consider when you book your ticket.

       When it comes to weighing the environmental pluses and the health and safety minuses, taking a flight that may cross the pole is a complicated equation. If you're an infrequent traveler, the polar flight probably makes sense. If you're pregnant, you might want to take the long route or stay home. And if you travel to Asia a lot, Fahey jokes, "Wear lead-lined clothes next time."

Crash Report Shows Confused Cockpit

Crash Report

The airline industry is expected to implement major changes in its training procedures—particularly those intended to help pilots quickly react and regain control in the event of high-altitude flight upsets following a report last week that shed light on the 2009 stall and crash of an Air France jet.

While cruising at 35,000 feet and nearly four hours into what seemed a routine overnight flight to Paris from Rio de Janeiro, Air France pilots got a stall warning and responded by yanking the nose of the plane up, instead of pointing it down to gain essential speed, according to information released Friday by French accident investigators.

Apparently confused by repeated stall warnings and reacting to wildly fluctuating airspeed indications, pilots of Flight 447 continued to pull back sharply on the controls for almost a minute—even as the Airbus A330 plummeted toward the water, according to the information released Friday.

The report raised questions about how seasoned pilots for a top airline, flying one of the industry's most advanced jets, violated such a fundamental rule of airmanship.

The aviation industry already implemented major changes in pilot training months before Friday's release, but the report is bound to set the stage for further training revisions, according to international safety experts.

Led by aircraft manufacturers Boeing Co. and Airbus—and supported by airlines and regulators on both sides of the Atlantic—new stall-recovery training programs have been developed to reiterate the importance of reducing the upward angle of the nose of the aircraft as pilots add power to regain speed and control.

While French investigators are months away from releasing their final conclusions and safety recommendations from the Air France probe, critics of traditional stall-recovery training are pushing for further changes to help pilots feel more comfortable manually controlling planes in various emergencies.

Claude Lelaie, a top Airbus safety official, told an international safety conference in Istanbul in March that the manufacturer for months had been advocating revised stall-recovery procedures emphasizing "more pitch down control" to push down the nose of the aircraft and reduce its "angle of attack," or the angle between the airflow and the longitudinal axis of the plane.

Specifically, the Airbus official told the conference that after the Air France crash, pilots for the first time were trained to recover from stalls at high altitudes, without the benefit of certain computer aids. "Pilots were afraid of that" technique in the past, he said, because standard simulator training assumed certain automated protections would remain in place.

Many of the same changes also are gaining momentum in the U.S., where various industry groups, union officials and government safety experts are mulling regulatory changes to lock in the new training approaches. The Federal Aviation Administration is considering updated simulator techniques and recurrent training requirements, and lawmakers also have been pushing for similar revisions.

Paul Kolisch, a U.S. airline pilot and senior flight instructor participating in that effort, believes traditional stall-recovery training has been too predictable and failed to reflect the nature of real-world emergencies. "The training is akin to synchronized swimming," he told the March conference in Istanbul. "It requires a good deal of skill and preparation, but has nothing to do with swimming safely across a river."

Likewise, Boeing Co. safety officials have urged enhanced stall-recovery training that is more realistic and suddenly confronts pilots with surprising flight-control difficulties, while also teaching crews to better understand the impact of automation on their responses.

The introduction of automation has made flying dramatically safer over the years. In the U.S., for instance, fatal accident rates are at record lows. But if pilots are taught to abdicate too much responsibility to automated systems, essential piloting skills can dull and aviators become too reliant on computers in emergencies.

That's particularly troublesome if onboard flight-control computers malfunction, disconnect or, as in the case of Flight 447, give conflicting information and warnings to pilots. "Pilots are starting to serve the automation, not the automation serving the pilots," said Bill Voss, president of the Flight Safety Foundation of Alexandria, Va., an independent advocacy group championing enhanced training. "It's almost like we have to train the pilots to know how to triage these situations."

The long-awaited factual report, though it doesn't explicitly say the pilots acted improperly, provides important new details about their actions during a dangerous loss of forward momentum that lasted more than three and a half minutes. Investigators already concluded that except for malfunctioning airspeed probes, there were no other mechanical, electrical or system errors.

The report paints a somewhat unflattering picture of a seemingly confused cockpit, with the crew making extreme inputs to their flight controls and the engines spooling up to full power and later the thrust levers being pulled back to idle. At one point, according to the report, both pilots sitting in front of the controls tried to simultaneously put in commands.

The preliminary findings offer "a strong piece of evidence that as an industry, we need to improve upset recovery training," said John Cox, a former airline pilot and accident investigator who now runs Safety Operating Systems LLC, a consulting firm based in Washington, D.C.

The senior captain on the flight, Marc Dubois, who was on a routine rest break in the cabin when the trouble started, rushed back to the cockpit and was present and observing the other pilots' actions during a large portion of the descent.

Air France praised the three pilots, who "demonstrated a totally professional attitude and were committed to carrying out their task to the very end," the airline said in a statement.

The carrier, a unit of Air France-KLM SA, noted that "the initial problem was the failure of the speed probes which led to the disconnection of the autopilot and the loss of the associated piloting protection systems."

The largest trade union representing Air France pilots, SNPL, said Friday the report "describes only part of the sequence of events experienced by the crew" and it awaits the full report.

Throughout the sudden descent, according to the report, "inputs made by the [pilot flying] were mainly nose-up," which reduced the plane's lift. Pilots are taught from their earliest training that if an airplane begins to stall and its wings have lost the lift to remain airborne, they should immediately push the nose down to regain speed, lift and maneuverability.

The report could provide ammunition for the lawsuits against Air France, though plaintiffs also are likely to pursue Airbus for how it handled airspeed-indication issues over the years.

The problems with the speed probes on the Air France plane, and others like it, were well known. They had a history of icing up and giving faulty readings. The probe's maker, Thales SA of France, declined to comment. Airbus and regulators had established procedures to handle such situations with the probes, which are called pitot tubes. These procedures focused on maintaining sufficient thrust and avoiding extreme maneuvers.

Airbus, a unit of European Aeronautic Defence & Space Co., said in a statement it is committed to continuing to provide support to the investigation "with the objective of identifying all potential lessons to be learnt."

About three hours and 40 minutes into the flight, when the airspeed-indication issue first cropped up and the pilots received their initial stall warning at around 35,000 feet, the report shows the crew maintained control and temporarily managed to stabilize the plane at an altitude above 37,000 feet. That took just under a minute.

But then with their jet basically flying level despite airspeed-sensors that continued to display unreliable readings, the pilots started to veer away from typical procedures, the data released Friday reveal. French investigators didn't comment on reasons for the crew's behavior.

Upon receiving a second stall warning, the crew increased engine thrust substantially—part of standard practice to cope with such a situation. But for the next 50 seconds, the pilot at the controls did something that safety experts consider anathema: He continued to pull the jet's nose up, despite the threat of worsening the stall.

About two minutes after the first problems—and with the captain back in the cockpit—the jet was falling at a rate of 10,000 feet a minute, comparable to dropping 15 stories a second in an elevator. Yet the plane's nose remained pointed sharply upward as the wings rocked side to side and its forward speed hovered around 100 miles an hour, too slow for a jetliner to fly.

"I don't have any more indications," one of the pilots said, perhaps referring to airspeed but possibly something else. "We have no valid indications." The report doesn't elaborate.

At that juncture, according to the report, both thrust levers were pulled back to idle. The report also said that both engines were operating and responding normally to pilot commands.

The report goes on to describe how roughly a minute later, with the plane already dropping to around 10,000 feet altitude, there were "simultaneous inputs by both pilots on the sidesticks" that control the aircraft, with one of the pilots trying to clear up the confusion by telling the other "go ahead, you have the controls." Pilots are trained to avoid such simultaneous commands.

The plane's data recorders stopped four minutes and 27 seconds after the autopilot kicked off, with the plane still dropping at roughly 10,000 feet a minute, tail down and slightly rolled to the left.

Air France has had a history of safety issues over recent years. After the crash of an Air France Airbus A340 on landing in Toronto in 2005 that resulted in no fatalities but destroyed the plane, the airline ordered a thorough study of its approach to safety. The airline later said most of the report's recommendations had been implemented.

After the 2009 crash, the airline commissioned another study of its practices by a panel of leading international safety experts. That report, which was delivered to the airline in January, found a lack of "strong safety leadership at all levels of management" that resulted in lax cockpit discipline and ineffective pilot training.

Air France said it was studying and implementing the report's recommendations.

India-Europe flights unaffected by ash cover as of now

NEW DELHI/MUMBAI: Indian air carriers Wednesday reported no cancellation of flights to Europe, despite volcanic ash from Iceland grounding about 500 flights in Britain alone and covering some part of the continent's air space.

"Our operations till midnight are on schedule. Any alterations due to the ash cover would be informed to the passengers," a senior Air India official with the operations arm of the airline told IANS.

According to the official, the ash cover was unlikely to affect the airlines' operations, as longer and safe routes were available with Air India.

"There is no such scenario of flight cancellations as operations are unlikely to be affected. The major cancellations are of domestic European flights."

Currently, the flag carrier is India's largest flight operator to Europe with 30 flights to and from the continent on Boeing 777LR (long range) aircraft.

Other leading carriers like Jet Airways and Kingfisher Airlines, which operate flights to Europe, also confirmed that there was no cancellation or disruption due to the ash cover so far.

"We are, however, keeping a close watch on the situation to avoid chaos," a senior official at the Vijay Mallya-promoted Kingfisher Airlines told IANS.

The senior official added that if the situation worsens, the airline may take measures like route alteration to avoid the ash cover zones.

Kingfisher Airlines currently operates four daily flights between India and Britain, including Delhi-London and Mumbai-London.

Jet Airways, which has a considerable presence on the European continent with its international hub based in the Belgian city of Brussels, said the situation was under control and none of its 18 daily flights, including six connecting flights to North America, were affected.

Jet Airways operates 12 flights from India to Europe including return flights, while six flights have a stopover in Europe before they either move on to North America or return back to India. The company operates its operations on Boeing 777 ER (extended range) aircraft and Airbus A330 aircraft.

The ash cloud from Iceland's erupting Grimsvotn volcano now threatens northern Europe. British Transport Secretary Philip Hammond said airports in Britain should return to normal Wednesday as the ash cloud went down from 12 miles to just two.

Around 500 flights were cancelled in Britain after the eruption began on Saturday, leaving passengers stranded at certain Scottish and northern England airports.

Aviation experts assert that an aircraft passing through the ash clouds may experience technical difficulties like engine failure.

The airline safety risk assessment procedures explains this anomaly as an increase of suspended particles in the engine's turbines, which have the potential to choke the engine to an halt.

Last year a similar spectacle of ash cover blocking airline traffic in one of the busiest aviation sector of the world was witnessed in April. According to the International Air Transport Association ( IATA), it cost $1.8 billion and set back the global economy by $5 billion.

Cargo numbers: Recovery ahead

    As a rough rule of thumb, Brian Pratte says, the economic impact of an air cargo flight is 10 times greater than the impact of a passenger flight.

“Those boxes didn’t move themselves,” says Pratte, director air service and cargo development at Reno-Tahoe International Airport.

And that translates into good news for the northern Nevada economy as the amount of cargo handled at the airport during March increased more than 19 percent from a year earlier.

In fact, cargo shipments through the airport have been up year-over-year for 14 consecutive months.

Two big trends hold promise of spurring air cargo traffic even further.

One is the rapid development of new Internet fulfillment operations in northern Nevada. In recent weeks, Urban Outfitters, Toys“R”Us and GSI Commerce all have announced plans for big new centers that will fill orders placed by online customers.

While many of those orders will travel by truck, history shows that air cargo operations will benefit as well.

One statistic tells the story: Most months, somewhere between 150 and 200 cargo flights land at Reno, about 10 flights each weekday.

But last December, when Amazon.com distribution at Fernley and Barnes and Noble distribution in Reno were filling holiday orders, the number of cargo flights topped 300.

A second factor that could drive air cargo growth is the major push undertaken by Pratte and other airport officials to open direct cargo service between Reno and Chinese destinations.

“We are very diligent about building capacity,” says Pratte.

He met with nearly three dozen Chinese shipping companies during a recent Asian visit, building their awareness of Reno as a potential gateway to U.S. markets.

A big sales pitch: A flight between Beijing and Reno is 300 fewer nautical miles than the trip between Beijing and Los Angeles. That can cut $4,000 from the fuel bill of a 747 cargo aircraft, even without accounting for traffic delays in the skies above Los Angeles.

Airport executives believe, too, that there’s potentially plenty of cargo to fill aircraft headed west from Reno to Asia. About 50 percent of the international air cargo from northern Nevada destinations currently is trucked to Los Angeles before it’s loaded on aircraft, Pratte says.

The availability of good air cargo service is an important element in attracting new jobs to the region, says Todd McKenzie of McKenzie Properties, a Reno-based developer of industrial, office and commercial properties.

“Air cargo is important for global trade and is used for transporting high-value-to-weight items in a timely manner,” says McKenzie. “Having a strong air cargo capability along with our rail, trucking and overall geographic location bodes well for our future economic growth. It enhances our overall distribution mix.”

Pratte notes that strong air cargo service at Reno-Tahoe International Airport ripples through a wide region.

The airport sees potential markets for air cargo within a one-day truck drive of Reno — an area that includes parts of Oregon and Idaho as well as northern Nevada and the Sierra region of northern California.

Endeavour preparing for the trip home – TPS clearance overview

Endeavour preparing for the trip home

        After nearly 12 days of docked operations with Space Station Alpha, the Space Shuttle Endeavour, NASA youngest Shuttle orbiter, departed the international outpost to begin her final journey home. Thanks to the superb work by her flight crew and her thousands of support staff on terra firma, Endeavour’s Thermal Protection System (TPS) was formally cleared for reentry thanks in large part to Endeavour’s former Orbiter Boom Sensor System.
Post Undocking TPS Damage Assessment Team (DAT) clearance:

       Following the preliminary clearance of all areas of Endeavour’s TPS on FD-5, less the multi-tile gouge area between Endeavour’s Right Hand MLGD (Main Landing Gear Door) and Right Hand ET Umbilical door, Endeavour’s flight crew was instructed to proceed with a focused inspection of the damage location.

         Prior to that, all Damage Assessment Team (DAT) assessment of OBSS (Orbiter Boom Sensor) data and FD3 RPM (R-bar Pitch Maneuver) photography from the ISS confirmed that Endeavour’s two ET umbilical well doors were closed, that there were no upper flight surface protrusion of any kind, and that six of the seven lower damage sites had been cleared without the need for a Focused Inspection (FI).
Following the FI of the three-tile damage location, lovingly dubbed “The Maine” damage because of its remarkable resemblance to the U.S. state of Maine, a detailed characterization of the damage was compiled.

        From this, it was confirmed that all tile material was still intact in all areas with no exposed filler bar material; no cracks were identified; the dark area of TPS as seen from RPM imagery was an area of abrupt damage depth change – as expected; all thermal stress assessments revealed no structural overtemp issues for reentry; a “small area” of TPS bondline overtemp would occur during reentry but is acceptable for reentry due to its distribution over three tiles; all TPS and structural margins were well within safety limits for reentry.

        Thus, the TPS DAT unanimously recommended clearing Endeavour’s entire Thermal Protection System for reentry in emergency return cases and for nominal EOM (End of Mission) reentry pending the completion of the Docked Late Inspection (DLI).

Detailed Focused Inspection damage site clearance overview:

    Following the detailed and fascinating Focused Inspection of the “Maine” damage site, photographic and laser measurement data revealed that the damage was 0.89 inches in depth, +/-0.04 inches, and remained above the filler bar.

This means that tile margin exists in all areas of the damage cavity, or what the post-FI inspection presentation – available for download on L2 – classed as a “dense layer.” (View Anaglyph slide left with 3D glasses).

In all, the damage location is 0.89 inches in depth, 2.95 inches in length, and 2.43 inches in width.

In fact, the TPS clearance presentation notes that there are very few areas of missing material and no cracks radiating outward or downward from the main damage site.

Furthermore, views of the damage location obtained from the OBSS’s Laser Dynamic Range Imager (LDRI) confirmed that sections – but not all – of some AMES gap fillers were missing, indicating that the “Impactor had enough energy to damage multi-layer AMES gap filler.”

However, it appears that the AMES gap fillers had an unintended positive consequence as “Adjacent tile damage size [was] reduced by the presence of AMES gap filler.”

In comparison to a similar tile damage event on the STS-118/Endeavour mission, the STS-118 damage was 3.48″ x 2.31″ x 1.12″, was located at Xo 1260 Yo 123 Zo 269, and carried a tile depth of 1.12 inches.

STS-134/Endeavour’s damage was 3.22″ x 2.49″, was located at Xo 1243 Yo 106 Zo 267, and was located on a tile with a thickness of 1.04 inches.

Based on analysis conducted during the STS-118 mission, that mission’s damage was found, based on on-orbit information analysis, to have a Mach 16.7 Boundary Layer Transition (BLT) time. STS-134′s damage is predicted to have a Mach 12 (nominal) BLT time.

All STS-134 FI damage was further found to have baseline aeroheating, BLT, Boundary Layer Wedge, Cavity Heating, Thermal Analysis, Tile Stress, and Stress indicators in Model Category “A” – indicating that “Baselined model used within model limitations or intended use.”

A maximum temperature calculation for the FI damage locations was created, and “Due to flow orientation, assessment [was] performed in both the aligned and cross-flow orientations of the simplified cavity,” notes the TPS DAT clearance overview presentation.

Based on these parameters, a maximum structural temperature of 219-degrees F and a maximum RTV bondline local temperature of 1,194-degrees F are expected during entry on Wednesday morning. The maximum structural temperature allowed is 350-degrees F, leaving high structural margin.

Nonetheless, the total RTV bondline temperature does exceed nominal limits; however, RTV bondline temperature “over 625°F is limited to 6 inches squared distributed over 3 tiles.” For the damage site on STS-134/Endeavour, the aligned flow max temperature is predicted at a modeled rate of 5.75 inches squared with an actual in-flight temp on the critical tile of 4.06 inches squared – both meeting the design requirements