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Please see landing distance page 2

actual landing distance2. is a number provided by Bombardier engineers and is printed in the performance chapter of Comair’s Flight Standards Manual.

dispatch landing length3. is a number used by airline dispatch-ers to determine if it is legal to send an aircraft to a particular airport based on the forecast weather conditions at the flight’s estimated time of arrival.

None of these landing-length num-bers are the same, although all are calculated by assuming the aircraft is 50 ft. above the landing threshold at Vref. Each number also accounts for wet or contaminated surfaces.

This article will provide you with the tools to sift through the various charts, tables, and manuals to answer the critical question:

do i have enough pave-ment to stop my air-plane on this runway with the current weather and runway condi-tions?

To answer this, you must first de-termine where the aircraft’s main wheels touch the runway.

AeroData’s TLR report assumes the CRJ100/200, 700, and 900 series aircraft will touch down at 1,560 ft. past the runway threshold. On a pre-cision instrument approach runway, this is on the first distance marker past the large solid white aim point markers (see Figure 2).

If you fail to touch down at 1,560 ft., it will be very difficult to stop in the distance depicted in the TLR.

A Comair Central Air Safety Committee PublicationWinter 2010

Four U.S. airline crews have slid off runways when land-ing during the past five years. Each overrun occurred on a

runway longer than 6,000 ft. Four of the five occurred in snowy condi-tions, and four of the five overruns occurred at night. These accidents reveal that even experienced pilots can miscalculate the distances needed to stop in adverse weather.

Comair, the airline industry, and the Federal Aviation Administration have taken a hard look at why runway overruns occur. New guidelines have been implemented so pilots have more information on the flight deck to determine if they have enough runway length to stop their aircraft.

But despite these efforts, it is still easy to get confused about landing-length numbers. Comair must cal-culate three different landing-length numbers on every flight.

aerodata’s takeoff and land-1. ing Report provides a landing distance from threshold number. This number is printed on the bot-tom of the dispatch release.

As airline pilots, all of us have made hundreds of landings and have an intuitive understanding of how much runway it takes to stop an airplane. On a nice day, we always have enough pavement for comfort. But what happens when it’s a snowy night with a 5-knot tailwind and a braking action report of poor by the previous aircraft? Suddenly, 6,000 feet of runway may not seem so long.

How to Assess Your Landing

Distance in Bad Weather

By Dean Weaver CRJ50 First Officer

1 How to Assess Your Landing Distance in Bad Weather

4 Recent U.S. Airline Overrun Landing Accidents

5 Factors Affecting Landing Distance7 Aviation Safety Action Program Update

InsIDe…

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landing distanceContinued from page 1

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Please share any ideas, questions, or comments you have with us.

Editor: Dean Weaver

E-mail: Dean.Weaver@alpa.org

Mail inquiries to: Comair MEC

Attn: Leading Edge 3490 Olympic Blvd., Suite 120

Erlanger, KY 41018

The Leading Edge is a quarterly publication produced by volunteer Comair pilots who are members of ALPA’s Central Air Safety Committee. The goal of the commit-tee is to promote and enhance safety at Comair.

Please see landing distance page 3

To arrive at this touchdown point calculation, Comair check airmen evaluated hundreds of flights dur-ing line checks and watched aircraft land from control towers in CVG and LGA. The average touchdown point from those landings was 1,560 feet for all Comair aircraft. This number was given to AeroData. It is used as a baseline for calculating landing length on every TLR. AeroData then applies a 15 percent buffer to the total landing distance.

These numbers can be corrected for wind, no thrust reversers, and wet or contaminated runway surfaces. They assume maximum use of reverse thrust (if available/utilized) and maximum braking to achieve the stopping distance. Knowing this, you can calculate your own personal landing distance minimums based on where you typically touch down.

The TLR landing numbers were generated by Comair as a result of SAFO 06012. The Safety Alert for Operators was issued by the FAA on August 31, 2006, after the Southwest Airlines overrun at MDW airport. It requests all air carriers re-evaluate the landing-distance numbers they provide to pilots. Advisory Circular 91–79 issued November 6, 2007, tells operators of all turbine-powered

aircraft how to calculate landing distances and what techniques pilots should use to land in the shortest possible distance.

The FAA is urging all air carriers to base the new landing-distance numbers on a realistic touchdown point and add a 15 percent safety buffer. These landing-length num-bers give pilots a more realistic idea of how much runway they need to stop. However, the FAA still requires operators to provide Actual Land-ing Distance numbers to pilots so a suitable runway isn’t overflown in the event of a time-critical emergency.

Comair’s Actual Landing Distance numbers are shorter than AeroData’s TLR landing numbers and can still be found in Volume I of the Flight

Standards Manual. This number is calculated differently than the TLR number in two significant ways.

The Actual Landing Distance number 1. is derived from Bombardier test pilots flying new aircraft. To cer-tify the CRJ under Part 25 Federal Aviation Regulations, Bombardier’s pilots were able to touchdown firmly at exactly 1,000 ft. from the runway threshold and apply maximum brak-ing to stop in the stated distance. The 1,000 ft. touchdown is for dry and wet landing numbers. Contami-nated runways assume a touchdown at 1,500 ft.

The Actual Landing Distance number 2. does not have a 15 percent safety

TOUCHDOWN ZONE3000 FT.

1,000 FT. TOUCHDOWN − Touchdown for actual landing distance calculation

1,560 FT. TOUCHDOWN – Touchdown points for TLR landing distance calculation (accounts for �are at landing)

Aircraft crosses the runway threshold at 50 ft. above the ground at Vref

3Winter 2010

landing distanceContinued from page 2

buffer added to total landing dis-tance. It is the absolute minimum stopping distance with a test pilot at the controls of a new aircraft.

Comair asks pilots to apply Quick Reference Handbook (QRH) land-ing corrections to the Actual Land-ing Distance number, not the TLR number. For example: An anti-skid inboard and outboard failure occurs, so the QRH applies a 75 percent addition to landing distance. This correction must be added to the Actual Landing Distance in the FSM, not the TLR landing distance.

Dispatchers use a third landing number when determining if a flight is legal to depart to an airport. A word of warning, the Dispatch Land-ing Field Length number is based on the longest suitable runway at the airport, which may not be the landing runway at the time of arrival.

Dispatch Landing Field Length is a pre-departure requirement based on Federal Aviation Regulation 121.195 and 121.197. It states that a tur-bine- powered transport category aircraft must land and come to a full stop within 60 percent of the effec-tive runway length. You can divide the Actual Landing Distance number (dry runway) in the Flight Standards Manual for the aircraft’s weight by 0.6 to get the Dispatch Landing Field Length.

For example: The Actual Landing-Dis-tance is 3,800 ft. 3,800/0.6 = 6,333 ft. So, a suitable runway of 6,333 ft. is required for at least one runway at the destination airport.

An additional 15 percent is added to the dry Dispatch Landing Length for a wet runway or low visibility and another 15 percent for a wet runway and low visibility. These Dispatch Landing Length numbers are depict-ed in a table in the Flight Standards Manual, but are only pertinent when dispatching an aircraft.

When en route, it is up to you as the pilot to determine the landing dis-tance needed to stop your aircraft. The TLR provides the most realistic landing-distance numbers you can expect as long as you touch down

at least 1,560 ft. from the threshold and use maximum reverse thrust and braking. Make sure you use the correct TLR numbers for the runway surface, i.e., wet or contaminated, and correct for a tailwind.

In an emergency or aircraft sys-tem malfunction, the QRH correc-tions must be added to the Actual Landing Distance numbers, giving you a best-case landing perfor-mance number for landing assess-ment. The corrections are added to the shorter Actual Landing Distance number so a crew will not rule out a nearby runway during a time-critical emergency in search of a longer landing strip. If time permits, you may want to consider applying these QRH corrections to the TLR number to get a picture of landing length required in a less than best case landing.

Recent history has shown that the best way to keep your aircraft out of the dirt is to take a few minutes to conduct a thorough landing-distance assessment using the most recent runway conditions. The second best way to prevent an overrun is to touch down within the first 1,560 ft., since that is the touchdown point the TLR numbers are predicated upon.

36

TOUCHDOWN – 1,000 ft. from thresholdTouchdown point for calculatingActual Landing Distance—dry/wet

TOUCHDOWN – 1,560 ft. from thresholdTouchdown point for calculatingTLR Landing Distance

RUNWAY TOUCHDOWN ZONEEvery 500 ft.

Figure 2: On a runway with presicision instrument markings the ILS glideslope intersects the runway at 1,000 feet, which is the beginning of the aim point markings. Comair’s landing distance numbers depicted on AeroData’s TLR add 560 feet to account for the flare so the touchdown point is 1,560 feet from the threshold.

Recent history has shown that the best way to keep your aircraft out of the dirt is to take a few minutes to conduct a thorough landing- distance assessment using the most recent runway conditions.

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april 12, 2007 (12:43 a.m.) The crew of Pinnacle Airlines Flight 4712 operating as Northwest Airlink from Minneapolis–St. Paul Inter-national Airport (MSP) to Traverse City–Cherry Capital Airport (TVC) at-tempted to land a CRJ 200 on Runway 28, measuring 6,501 in length.

The wind was 020 at 8 knots (an 8-knot crosswind). The ASOS reported visibility of 1/4 mile with heavy snow, vertical visibility of 200 ft., three minutes prior to the accident. Airport personnel told the crew they estimated a 1/2 inch of snow on the run-way prior to landing. The

aircraft touchdown occurred 2,400 ft. beyond the threshold. The CRJ came to rest 100 ft. beyond the end of the pavement after the nosewheel separated from the airplane. There were no injuries to the 49 passen-gers, three lap children, and three crewmembers.

Probable cause: The NTSB deter-mined the pilots failed to perform a landing distance assessment tak-ing into account the contaminated runway conditions. Pilot fatigue was a contributing factor.

Pinnacle Airlines Flight 4712

shuttle America Flight 6448

dec. 8, 2005 (7:14 p.m.) The crew of Southwest Flight 1248 from Baltimore-Washington International Airport (BWI) to Chicago Midway Airport (MDW) at-tempted to land on Runway 31C measuring 6,522 ft. in length.

The weather before landing was reported at a 1/2 statute mile with snow, freezing fog, and a broken ceiling of 400 ft. Wind was 090 at 11 knots (an 8-knot tailwind). Braking action was reported good for the first half of the runway and poor the second half. Runway 31C was the only runway available to landing aircraft due to approach minimums and weather.

The Boeing 737 touchdown was 1,250 ft. beyond runway threshold. The captain had difficulty unlocking the thrust reversers, and they were not fully deployed until 15 sec-onds after touchdown. The aircraft rolled through a blast fence and perimeter fence, and onto a roadway. A 6-year-old boy in one of the vehicles struck by the aircraft died. The five crewmembers, along with the 98 passengers, survived; 18 were injured.

Probable cause: The NTSB determined the probable cause was the pilots’ failure to use reverse thrust in a timely manner. A contributing factor was the delay in reverse thrust due to confusion over the autobrake system. Southwest’s failure to provide its crews with procedures for calculating landing distances that would provide for a margin of safety was also a factor.

southwest Flight 1248

Feb. 18, 2007 (3:06 p.m.) The crew of Shuttle America Flight 6448 operating as Delta Connection from Atlanta Hartsfield-Jackson International Airport (ATL) to Cleveland Hopkins International Airport (CLE) attempted to land on Runway 28 measuring 6,017 ft. in length.

The RVR for Runway 28 was reported at 6,000 ft. with a braking action of fair. Winds were 310 at 12 knots (an 11 knot crosswind). The glideslope was reported unusable. Once inside the final approach fix, the RVR decreased to 2,200 ft. The crew encountered strong, gusty winds dur-ing the flare and touch-down and reported losing sight of the runway 30 feet before touchdown.

The aircraft touchdown was 2,900 ft. beyond runway threshold. Despite the use of maximum reverse thrust and braking, the Embraer 170 came to a stop 150 ft. past the end of the runway in the snow-covered grass. All four crewmembers and 71 pas-sengers survived, with three minor injuries reported.

Probable cause: The NTSB determined that the crew should have executed a missed approach when visual cues to the runway were not distinct and identifiable. Contributing factors were the long landing and the decision to use ILS versus local-izer minimums, along with pilot fatigue.

American Airlines Flight 331dec. 22, 2009 (10:22 p.m.) The crew of American Airlines Flight 331 from Miami International Airport (MIA) to Kingston–Norman Manley International Airport (KIN) attempted to land on Runway 12 measuring 8,900 ft. The pre-liminary investigation shows the Boeing 737 touchdown was 4,100 ft. from the threshold with a 14-knot tailwind. The aircraft skidded across a road and slid to a stop on the beach with the fuselage cracked and right engine ripped off. Heavy rain showers were reported at the airport before the accident, which is under investigation. The six crewmembers and 148 passengers survived the accident.

Probable cause: To be determined.

Shuttle America Flight 6448, an Embraer 170, slides through a perimeter fence off the end of Runway 28 at Cleveland-Hopkins International Airport on Feb. 18, 2007. Photo taken by the NTSB, courtesy of the Flight Safety Foundation

Recent U.s. Airline Overrun Landing Accidents

Pinnacle Airlines Flight 4712 comes to rest at the end of Runway 28 at Traverse City–Cherry Capital Airport on April 12, 2007. Photo taken by the NTSB, courtesy of the Flight Safety Foundation.

5Winter 2010

Please see Factors affecting landing

distance page 6

Factors Affecting Landing DistanceBy Dean Weaver CRJ50 First Officer

The two pilot-controlled factors that contribute the most to landing distance are excess airspeed and an extended flare.

Bleed off 5 knots of excess airspeed in an extended flare, and the aircraft can easily float to the end of the 3,000 ft. touchdown zone, according to data supplied by Federal Aviation Administration Advisory Circular 91–79.

Making a landing assessment is criti-cal when runway surfaces conditions get slippery. These calculations must include aircraft weight, airport winds, and type of runway contamination.

But this is not enough to prevent an accident. Ultimately, stopping the aircraft within a published landing dis-tance comes down to pilot technique.

“I would have to say that 95 percent of the runway excursions we’ve stud-ied have involved incidents where the numbers would have told the pilots that landing on the runway would not be a problem,” said Jim Burin, director of Technical Programs for the Flight Safety Foundation. “But those numbers don’t always help pilots make sense of really important things like touchdown point and aircraft speed. The numbers are only accurate if you use actual runway conditions at the time of landing.”

The top reasons for overruns are things that pilots control:

Failing to go-around when vis-1. ibility is lost or the approach is unstabilized

Landing long2.

Ineffective braking, especially 3. when landing on a contaminated runway

These findings come from the Flight Safety Foundation, a nonprofit avia-tion organization in Alexandria, VA, that analyzed 1,429 commercial turbojet and turboprop landing excur-sions that occurred worldwide from 1995 to 2008.

The foundation discovered that excur-sion accidents are 40 times more likely to occur than runway incursion accidents. It defines a runway excur-sion as any time an aircraft leaves the runway on either takeoff or landing.

AC 91–79 urges all turbine pilots to maintain a stabilized approach and re-alize that landing technique plays a vi-tal part in preventing runway overruns. A pilot who adds just 5 knots to Vref for gusty winds may add up to 250 feet to the stopping distance on a wet runway, according to the advisory cir-cular. And if the pilot bleeds off those 5 knots of airspeed in the flare prior to touchdown, the landing distance swells by an additional 1,250 ft.

Combine the stopping distance and float from the 5 knots of additional airspeed, and total landing distance increases by 1,500 ft above the published number. Add snow or a tailwind into the equation, and land-ing technique may double what the aircraft manufacturer considers to be the actual landing distance on wet or contaminated surfaces.

The amount of flare and excess airspeed are the biggest factors when it comes to piloting technique to achieve the published landing-distance numbers, but there are other conditions to consider. Some other factors include:

Wind: A 5 kt. tailwind can add 450 ft. to the actual landing distance on dry pavement, according to Comair’s Flight Standards Manual. But that 5 kt. tailwind adds 800 ft. when the run-way is contaminated with loose snow.

A crosswind adds distance to a land-ing since it requires the pilot to ex-tend the flare by a couple of seconds to remove the crab and lower the wing. The advisory circular estimates that this can add 460 ft. to landing distance.

threshold crossing Height: Being 50 ft. high over the runway threshold (100 ft. AGL) will add ap-proximately 1,000 ft. to total landing

A Comair crew lands on a wet Runway 27 at South Bend Regional Airport on August 17, 2004.

Photo Credit: Bruce Leibowitz, Airliners.net

6 ThE LEading EdgE

distance for all turbine powered air-craft, according to the Flight Safety Foundation’s Approach and Landing Accident Reduction Task Force.

Runway slope: Each one degree of runway down slope adds 10 percent to the total landing distance. Runway slope numbers can be found on the back of Jeppesen’s airport diagrams.

glidepath angle: Trying to sneak the airplane in beneath the glideslope can actually increase landing dis-tance. When flying a shallower glide-path with additional power, landing distance grows. The FAA states that flying a two-degree glidepath instead of a three-degree glidepath will add about 500 ft. to the landing distance.

Taking into account the aircraft weight, wind, and runway surface condition in a landing assessment is the first step in determining if there is enough runway to stop. Ask the tow-er for recent braking action reports. Review AeroData’s Takeoff and Land-ing Report and estimate where you believe the aircraft will touch down based on current wind conditions and your own landing technique.

If you believe it is unlikely the wheels will make contact with the runway before 1,560 ft., then add a buffer to your landing distance calculations. All TLR landing-length numbers are predicated upon a 1,560 ft. touchdown point.

FactORs aFFecting landing distanceContinued from page 5

the Flight safety Foundation issued a report in May 2009 identifying runway incursions as one of the top safety threats to commercial aviation worldwide.

They recommend the following strategies to prevent overruns:

Use a runway with an ILS or 1. precision approach path guidance to greatly reduce the risk of an overrun.

Obtain a timely report of the run-2. way surface condition and current winds at the airport. Falling snow can turn a good braking action report to poor in less than 15 minutes. Be wary of landing with any tailwind.

Consider all landing factors, includ-3. ing temperature, pressure, wind, runway contamination, runway slope, and aircraft landing weight in your distance calculation.

Good Crew Resource Manage-4. ment is essential. Follow stan-dard operating procedure; give a complete approach and go-around briefing early during the arrival process. Complete all checklists in a timely fashion, and keep distractions to a minimum on the flight deck.

Give yourself a safety margin 5. when considering landing distance.

Do not expedite the landing by 6. accepting a visual approach, especially at night or at unfamiliar airports. Always do the ILS ap-proach if available, and make sure the approach is stabilized 1,000 ft. prior to touchdown. Go-around if the approach is not stabilized.

In some cases, it may be prudent 7. to delay the landing by a few minutes to allow airport ground crews time to inspect or clear the runway, or provide you with a cur-rent runway surface report.

the Faa recommends the following techniques to bring an aircraft to a stop quickly

Stabilize the approach at 1,000 ft. above the touchdown zone 1. height. Maintain a three-degree glideslope with an optimal sink rate of 500 to 700 fpm not to exceed 1,000 fpm.

Cross the threshold at 50 ft. and at Vref, if possible.2.

Do not delay reducing thrust after crossing the threshold.3.

Land as flat as possible, being careful not to extend the flare.4.

Promptly bring the nosewheel to the ground after the mains 5. touch down.

Immediately apply maximum braking and allow the aircraft’s 6. anti-skid to do its job. Maximize use of reverse thrust as soon as all wheels are on the ground, being careful to maintain directional control.

7Winter 2010

UpdateAviation safety Action Program

ASAP Hotline 1-866-274-7088(Call within 24 hours at the end of the duty day)

Electronic reports are submitted to: www.comairsafety.com

ImPortAntASAP

Info:

The Event Review Committee, made up of Comair’s Corporate Flight Safety Office, the FAA, and ALPA Safety Committee, has been tracking the following safety trends:

RushingPlease slow down. The majority of ASAP reports have shown that mistakes occur when crews get in a hurry to complete tasks. It is the most common factor in reports and therefore the biggest safety threat at Comair. Pilots must take their time and be methodical, especially with the new checklists.

Fatigue CallsWe have seen a rise in fatigue calls, and we strongly urge pilots to call the ASAP Safety Hotline within 24 hours of a fatigue call. Making this call gives a pilot five days to file an ASAP computer report.

Safety is data-driven. ASAP allows us to track safety threats and trends. We realize how fatiguing it is to have less than eight hours behind a hotel door and then report to the gate 30 minutes before departure. The Com-pany also is scheduling airport breaks in excess of five hours after short overnights. Please file an ASAP so we can identify why pilot rest is being compromised—it is up to each pilot to assess his or her fitness to fly, and being well-rested is part of being fit.

Runway IncursionsFive runway incursions have been re-ported to ASAP since October. In two of these incursions, there was a loss of separation, and pilot deviations were filed against the crews. We have seen some common trends in these runway incursions:

The first officer is often heads- 1. down, completing checklists.

The first officer is on the number 2. 2 radio talking to the gate or ramp while the captain is listening to the number 1 radio.

We are asking all crews to recognize that any taxi can become high-threat when the first officer is heads-down completing checklists or using the number 2 radio.

to reduce the risk of a runway incursion:

NEVER accept a clearance to 1. cross a runway or hold on a run-way unless both crewmembers hear the original clearance. If unsure, ask ATC to read back the clearance.

Brief the first officer before landing 2. to “hold all checklists until nearby runways are crossed.” There shouldn’t be any hurry to recon-figure the aircraft after landing if there are nearby runways to cross.

Follow the new checklist and brief 3. every taxi for both departure and landing. Make sure both pilots agree with, and understand, the clearance after it is given. The route you have been cleared on may be very different from what you expected when you gave your initial briefing.

Altimeter errors/Crossing RestrictionsWARNING: The “Altimeters” cross- check on the new Arrival Checklist may not be read until the crew is descending through 10,000 ft. The cross-check has been moved to the Prior to Approach portion of the Arrival Checklist. This checklist may not be completed until only 30 miles from the airport.

Crews need to be extra diligent about cross-checking the altimeters when descending through 18,000 ft. and to make sure the correct setting is verified by both pilots. Waiting for the checklist item to be read may put both pilots at risk of an altitude deviation.

Altimeters are being set to the wrong number when descending through Flight Level 180. Sometimes it is a wrong setting like 29.35 vs. 30.35, or it is leveling off at FL 180 and pushing the Barometric Altimeter button prematurely, locking in the 29.92 setting. Both crewmembers should verbalize the altimeter setting to verify the number when descend-ing through FL 180. If unsure, query Air Traffic Control before descending through FL 180.