Source: http://www.bst-tsb.gc.ca/eng/rapports-reports/aviation/2010/a10h0004/a10h0004.asp
Timestamp: 2014-07-31 19:36:19
Document Index: 407234665

Matched Legal Cases: ['art 25', 'art 120', 'art 120', 'art 121', 'art 2', 'art 3']

Transportation Safety Board of Canada - Aviation Investigation Report A10H0004
Trans States Airlines LLC Embraer EMB-145LR N847HK
1.0 Factual Information 2.0 Analysis 3.0 Findings 4.0 Safety Action Appendix Summary
An Embraer EMB-145LR (registration N847HK, serial number 14500857), operated by Trans States Airlines LLC as United Express Flight 8050 from Washington Dulles International Airport, landed at 1430 Eastern Daylight Time on Runway 07 at the Ottawa/MacDonald-Cartier International Airport, and overran the runway. The aircraft came to rest 550 feet off the end of Runway 07 and 220 feet to the left of the runway centreline. The nose and cockpit area were damaged when the nose wheel collapsed. There were 33 passengers and 3 crew members aboard. Two of the flight crew and 1 passenger sustained minor injuries. Ce rapport est également disponible en français.
Before commencing descent, the flight crew received the Ottawa weather from the automatic terminal information service (ATIS). ATIS information Yankee was received at 1405, and Zulu at 1414. ATIS Yankee included the following information: Ottawa International Information Yankee, weather at 1336: wind 100° magnetic (M) at 8 knots, visibility 15 statute miles (sm), broken ceiling at 2800 feet above ground level (agl), overcast at 5000 feet agl, temperature 18°C, dew point 13°C, and altimeter 29.90 inches of mercury (in Hg); approach instrument landing system (ILS) Runway 07; landing and departing Runway 07 and 04; land and hold short operation (LAHSO); advise air traffic control (ATC) if unable; inform ATC that you have information Yankee.
The crew briefed for an ILS approach for Runway 07 at CYOW. The aircraft was vectored by ATC to a base leg at approximately 10 nautical miles (nm). At 1426, ATC advised the crew that the wind was 160°M at 10 knots gusting to 16 knots, with a visibility of 10 sm in light rain. During the final turn to intercept the localizer, the airport controller informed the crew that they were in the process of switching the active runway to Runway 14. The crew was given the option of continuing for Runway 07 or switching to Runway 14. Considering the increased flight time, the extra fuel that would be used to manoeuver the aircraft for Runway 14, and the fact that the aircraft was already established on approach to Runway 07, the crew elected to continue for Runway 07. The final approach course was intercepted at 7 nm. The aircraft began its final descent upon interception of the glideslope, at a position approximately 4.7 nm from the threshold, with the autopilot coupled. Nearing the final approach fix, 3.9 nm from the threshold, the landing gear was extended, the landing flaps were selected to 22°, and the autopilot was disconnected. At 1428, the control tower provided the crew with updated wind information of 160°M at 10 knots gusting to 16 knots. At approximately 1000 feet agl and 2.9 nm from the threshold, the airspeed was stable at 150 knots indicated airspeed (KIAS). Shortly thereafter, the windshield wipers were turned on, and the crew indicated that they had the runway in sight. When the aircraft descended through approach minimums, 200 feet agl and 0.3 nm from the threshold, the airspeed was 144 KIAS. The aircraft crossed the threshold of Runway 07 at 49 feet agl, at a speed of 139 KIAS. The aircraft did a very smooth touchdown, and the weight on wheels (WOW) switch momentarily activated at 1430:15, 1740 feet from threshold. At that point, the nose was still in the air, and the aircraft floated. Two seconds later, 2270 feet from the threshold and at a speed of 132 KIAS, the second WOW activated and the nose wheel came down (Appendix B). Video recordings at the time of landing showed that the runway was wet.
The first officer was depressing the brake pedals during the second WOW activation; all spoilers automatically deployed after the nose wheel was lowered to the ground. The first officer continued to apply brakes until maximum braking was commanded. Sensing a lack of deceleration, the first officer informed the captain, who then took control of the aircraft and applied maximum braking as well. The aircraft could not be slowed during brake application. he aircraft was on the centreline until approximately 200 feet before the end of the runway, where it veered left. The aircraft exited the paved surface of the runway at approximately 62 KIAS. It continued through the grass for approximately 120 feet, at which point there was a sharp downward change in elevation of about 2 feet. The nose gear collapsed rearward, but the aircraft continued to skid. It came to a rest 550 feet from the end of the runway and 220 feet left of centreline. The flight attendant initiated the evacuation procedure for the passengers. 1.2 Injuries to persons
The aircraft was substantially damaged after it exited the runway. 1.4 Other damage
Captain First officer Pilot licence
11 January 2010 15 February 2010 Total flying hours
2691 Hours, last 6 months
Although the captain's normal sleep pattern varied, his average sleep duration was reported as 6 to 7 hours of sleep between the hours of 2130 and 0800. On 15 June, the captain awoke at 0500 (0400 local), and commuted by aircraft from home in Sand Springs, Oklahoma, to Dallas, Texas, and then to KIAD, where the duty day started at 1601. After flying 3 legs, the crew ended their duty day at Greenville−Spartanburg International Airport (KGSP). The flight crew's original duty day was scheduled to end at 2238 in KGSP. However, due to weather and flight delays, they did not arrive at the hotel in Greenville until 0030 on 16 June.
The first officer reported normally obtaining an average of 7.5 hours of light sleep, which included a couple of awakenings per night. On 15 June, the first officer woke at 0400 and commuted from home in Charleston, South Carolina, to KIAD. The first officer obtained 4.5 hours of unbroken rest in the crew duty room from 0730 to 1200, followed the same work schedule as the captain, and went to sleep at the hotel in Greenville, South Carolina, at 0230. The first officer slept lightly, waking twice during the night for about 15 minutes each time, finally awoke and got up at 0800, took the 0900 bus, and started the duty day at 0925. The first officer likely obtained 5 hours of sleep in the 26.5 hours before the occurrence. The crew was provided with the minimum rest period of 9 hours, which included travelling to and from the airport. These work schedules conformed to the work/rest rules prescribed in United States Federal Aviation Regulations (FAR) Section 121.471. Nevertheless, the investigation determined that the pilots were concerned about experiencing fatigue during the work period before the accident. 1.6 Aircraft information
Manufacturer Embraer Inc.
Certificate of airworthiness Issued 10 February 2004
Records indicate that the aircraft was certified, equipped, and maintained in accordance with existing regulations and approved procedures. Nothing was found to indicate that there was any airframe failure or system malfunction before or during the flight. The investigation team calculated the landing weight of the aircraft as 39 352 pounds, using actual baggage weights and standard passenger weights. The weight and centre of gravity were within the prescribed limits for a flaps-22 landing on Runway 07. The EMB-145LR is a 50-seat regional jet manufactured by Embraer of Brazil. All EMB-145LRs are equipped with wing spoilers and an antiskid braking system to slow and stop the aircraft. On the ground, with the weight on the aircraft wheels, all 4 spoilers deploy automatically. Spoilers increase drag and assist braking by causing loss of lift by the wing, resulting in transfer of the weight of the aircraft from the wings to the landing gear. All operated normally.
The antiskid system modulates the hydraulic pressure commanded by the brake pedals, forcing the wheels to operate at or near the critical slip ratio,Footnote 4 where the maximum friction coefficient is developed. The system does not apply pressure on the brakes, but rather relieves it to avoid skidding. The BCU receives signals from the wheel-speed transducers located in each of the 4 main wheel hubs. When any one of the signals indicates a decrease in speed to below the average speed of the other 3 wheels, a skidding condition is assumed, and the brake pressure for the associated wheel is relieved. When that specific wheel's speed returns to the average speed of the others, the commanded braking pressure is restored. The brake-system components from the aircraft were tested by the brake manufacturer, with Transportation Safety Board of Canada (TSB) investigators in attendance. Nothing was found to indicate that there was any brake system failure or system malfunction.
The pressure of the main landing-gear tires was taken shortly after the occurrence. Tires 1, 2 and 3 indicated 160 pounds per square inch (psi), and tire 4 showed 158 psi, all of which were within the required 160 psi +/− 4 psi. A detailed examination of the tires revealed only minor damage (cuts and chunking). This type of damage is typical for tires striking foreign objects on the runway or on the ground after an excursion from the runway.
Before departure, the crew received a flight-release package from the company dispatch. The flight-release package contained all information pertinent to the flight, including current and forecast weather, winds aloft,notices to airmen (NOTAMs), and airport/runway analysis data. The flight-release package depicts performance data in the form of aircraft weight for take-off or landing, and any additional restrictions that may apply. On the day of the occurrence, the maximum landing weight permitted for Runway 07 at CYOW, with a flaps setting of 22°, was 42 549 pounds. The landing weight was calculated by the crew to be 39 262 poundsFootnote 5, which was well within the limits for a flaps-22 landing on Runway 07. TSB requested calculation of the aircraft's landing performance from Embraer. Embraer based its calculations on an aircraft configuration of flaps 22, a speed of 139 KIAS at 49 feet over threshold, the relevant runway data, the environmental conditions that existed at the time of the occurrence, and the same touchdown point of 2270 feet. As well, Embraer used the wet runway braking coefficient of friction for a smooth wet runway provided in FARs Part 25 for accelerate-stop distance. Footnote 6 Using only brakes and spoilers (landing performance excludes the use of thrust reversers), the aircraft should have come to a stop 6216 feet from the threshold, with slightly less than 1800 feet of runway remaining. However, according to the flight data recorder (FDR), the occurrence aircraft's speed was still 96 KIAS at that point.
The operation of the in-flight brake function was recorded during the initial climbout following the occurrence take-off from KIAD, indicating that the brake-control valves were supplying pressure to the individual brake assemblies. The FDR data showed that the main landing-gear wheels started spin-up approximately ½ second before the first WOW indication. The first officer's brake pedals were being depressed as the second WOW was recorded. The wheel-speed parameters indicated increasing wheel spin-up, with the right wheels accelerating faster than the left wheels. The first officer continued to depress the brake pedals as the nose landing gear touched down. Approximately 5 seconds after the second WOW indication, the pedal position increased momentarily to 86% Footnote 7 of maximum travel. At this point, the left main wheels were accelerating, matching the speeds of the right main wheels, which were decelerating. All 4 main wheel speeds declined at similar rates from this point. The brake pressures became active as wheel speeds increased above 50 knots. All 4 of the brake pressures recorded values between approximately 200 and 400 psi, which were significantly lower than the maximum possible brake pressure of 3000 psi. Typically, the peak brake pressure varies between 1000 and 2000 psi during landing, depending on the conditions. The first officer's brake pedals reached 95% of maximum travel at 1430:26, remaining at that position until near the end of the runway. The captain started to apply wheel brakes at 1430:26, following indications that the aircraft was sliding; both pilots were applying the brakes from this point on until the aircraft overran the runway. For the last 1500 feet, the antiskid system was cycling, attempting to modulate the brake pressure (Appendix I).
The aircraft was approximately 600 feet from the end of the runway, proceeding at a ground speed of 82 knots, when the antiskid system let the brake pressures on the main wheels increase. The brake pressures increased to a range of 600 to 750 psi on the left main wheels and to a range of 300 to 500 psi on the right main wheels, indicating that there were better friction characteristics on the left side than on the right side. At this point, the aircraft's heading of 070°M began to decrease at a rate of approximately 6° per second. The captain's rudder force increased to nearly 120 pounds on the right pedal, while the first officer's rudder force increased to approximately 80 pounds on the right pedal. At the same time, the control wheel was being turned to the right by about 6° to 7°. The lateral acceleration recorded increasing negative g, Footnote 8 initially reaching approximately −0.3 g. The negative lateral g was consistent with a nose-left skidding motion as the aircraft approached the end of the runway. The FDR did not provide any parameters to determine if the tiller was used to steer the aircraft to the left of centreline. 1.6.6 Aircraft braking coefficient
To understand the operation of the brake system during the previous landing on a dry runway and during the occurrence landing on a wet runway, the calculated braking coefficient for both landings was compared with the brake pressure and brake-pedal position. During the previous landing, the braking coefficient and the brake pressure increased with an increase in brake-pedal position. When the brake-pedal travel increased from 5% to 50%, the braking coefficient increased from 0 to 0.3, and the brake pressure increased from approximately 200 psi to approximately 900 psi. These values of brake-pedal position, brake pressure and aircraft braking coefficient were typical for an aircraft landing on a dry runway. For the occurrence landing, the brake-pedal position went from 0% to 95%, while the braking coefficient and brake pressure remained constant at 0.07 and 200 psi, respectively. These values were much lower than those for the previous landing. The aircraft braking coefficient of friction calculated for the occurrence ground roll was compared with the wet runway braking coefficient of friction (adjusted for a fully modulated antiskid system) used by Embraer as per FAR 25.109(c). The comparison showed that the occurrence aircraft had a braking coefficient significantly lower than that predicted by the smooth wet runway equations in FAR 25.109(c)(1). Another comparison was made between the FDR data from the occurrence ground roll and brake-system test data obtained from Honeywell for the ground-roll phase of wet runway landing. The test was conducted in an aircraft under the same conditions and with the same configuration as the occurrence aircraft. The test showed that braking performance by the occurrence aircraft was as expected, and that the brake system on the occurrence aircraft performed as designed. The test also indicated that the braking coefficients of friction for both landings were similar and significantly lower than that predicted by the smooth wet runway equations in FAR 25.109(c)(1).
As well, investigations by the National Transportation Safety Board (NTSB) into a number of occurrences indicated that the wet runway braking coefficient of friction during the landing phase was significantly lower than that defined in the FAR 25.109(c)(1). 1.7 Meteorological information
On 16 June 2010, light rain was reported on the 1100, 1200 and 1300 aviation routine weather reports (METARs), but not on the 1400 observation. Rain had started falling again at CYOW at 1418, and continued to fall after the accident occurred. The 1418 special weather observation (SPECI), issued at 1426, reported the following conditions: wind 150° true (T) at 12 knots, visibility 10 sm, light rain, overcast at 2300 feet agl, temperature 16°C, dew point 13°C, altimeter 29.86 in Hg. 1.7.2 Forecast weather
A terminal aerodrome forecast (TAF) for CYOW, valid from 0800 on 16 June 2010 until 0800 on 17 June, was issued at 0738 on 16 June, with the following information: wind 100°T at 8 knots, visibility 6 sm, and overcast ceiling at 12 000 feet agl; from 1100: wind 100°T at 10 knots, visibility 6 sm in light rain, scattered clouds at 3000 feet agl, and overcast ceiling at 6000 feet agl; from 1200: wind 120°T at 10 knots gusting to 20 knots, visibility 6 sm in light rain and mist, scattered clouds at 800 feet agl, and overcast ceiling at 3000 feet agl; temporary condition between 0800 and 1400: visibility 3 sm in moderate rain showers and mist, and overcast ceiling at 2000 feet agl. An updated TAF for CYOW was issued on 16 June 2010 at 1044, valid from 1100 on 16 June until 0800 on 17 June, as follows: wind 070°T at 8 knots, visibility 6 sm in light rain, scattered clouds at 3000 feet agl, and overcast ceiling at 6000 feet agl; from 1200: wind 120°T at 10 knots gusting to 20 knots, visibility 6 sm in light rain and mist, scattered clouds at 800 feet agl, and overcast ceiling at 3000 feet agl; temporarily between 1200 and 1400: visibility 3 sm in moderate rain showers and mist, and clouds overcast at 2000 feet agl; from 1400: wind 120°T at 10 knots gusting to 20 knots, visibility 6 sm, and clouds overcast at 2000 feet agl; temporarily between 1800 and 0300 on 17 June: visibility 6 sm in mist, and overcast ceiling at 800 feet agl. The TAF for CYOW issued on 16 June 2010 at 1338, valid from 1400 on 16 June until 1400 on 17 June was as follows: wind 090°T at 12 knots, visibility 6 sm in light rain, broken ceiling at 4000 feet agl, and overcast at 6000 feet agl; temporarily between 1400 and 1700: visibility 2 sm in moderate rain showers and mist, and overcast ceiling at 700 feet agl. All of the foregoing TAFs indicated a possibility of rain during the expected arrival time of LOF8050. 1.7.3 Accident check observation
Precipitation is reported by type and by intensity, which is described as light, moderate or heavy. Intensity is determined either by visual evaluation or by measurement of rate. The intensity of rainfall at CYOW is determined by visual evaluation. The amount of rainfall at CYOW is normally measured and recorded in 6-hour periods to satisfy synoptic Footnote 11 reporting requirements; a standard rain gauge with a funnel and graduated cylinder is used. The observer must visually read the amount of water in the collection cylinder.
Using information provided by the City of Ottawa, the TSB determined that the total accumulated rainfall from 1418 until the aircraft landed was approximately 2.0 mm. A review of the 5-minute cumulative data for this period reveals a rainfall intensity of 4.8 mm/hour Footnote 12 over the first 5 minutes of rainfall, increasing to approximately 7.2 mm/hour at the time LOF8050 landed. Based on the Environment Canada Manual of Surface Weather Observations (EC MANOBS) chart in Section 3.9.5 (Appendix C), this intensity would equate to moderate rainfall at the time that the occurrence aircraft landed. The onset, or end, of precipitation is one of the criteria identified in EC MANOBS 10.3.5.6[c] for issuing a SPECI observation. However, at the time of the occurrence, in accordance with EC MANOBS, once rainfall intensity was reported, there was no requirement to report a change in the intensity until the next METAR was issued. In this occurrence, light rain was reported on the 1418 SPECI observation. Since November 2010, when Amendment 75 to Annex 3 of the International Civil Aviation Organization (ICAO) took effect, a SPECI shall be issued at the onset, at cessation, or upon a change in intensity of freezing precipitation, moderate or heavy precipitation, and thunderstorms (with precipitation).Footnote 13
As a result of the runway overrun accident of an Airbus A340 at Toronto/Lester B. Pearson International Airport in 2005, the Board issued Recommendation A07-06, Footnote 16 which stated that "The Department of Transport require all Code 4 runways to have a 300-m runway end safety area (RESA), or a means of stopping aircraft that provides an equivalent level of safety." The latest response Footnote 17 from TC regarding Recommendation A07-06 states that TC plans a risk assessment to establish RESA criteria at Canadian airports. The stated objective for this risk assessment is to collaborate with industry to establish a RESA length on a case-by-case basis.
1.10.3 Preferential runway Due to published noise-abatement procedures for turbojet aircraft at CYOW, Runway 07/25 is used a large percentage of the time.
Over time, the skid resistance of runway pavement deteriorates due to a number of factors, such as mechanical wear, polishing action from aircraft tires rolling or braking on the runway surface, and accumulation of contaminants. Runway contaminants include rubber deposits, dust particles, jet fuel, oil spillage, water, snow, ice, and slush, all of which can cause loss of friction on runway pavement surfaces. The effect of these factors is directly dependent on the volume and type of aircraft traffic. Footnote 20 Done on a regular basis, runway friction testing assists in determining whether corrective maintenance action is required to restore a runway's friction characteristics, or whether such maintenance must be planned. The runway coefficient of friction is measured using a Saab Surface Friction Tester with a self‑wetting capability that, as per TC guidelines, creates a 0.5-mm layer of water on the runway. TP312E contains the following standards, Footnote 21 which require the airport to react when the average friction values for a runway fall below specified levels:
9.4.2.4 Standard − Corrective maintenance action shall be taken [emphasis added] when: the average coefficient of friction for the entire runway is below 0.50; or any areas of a runway surface that are 100 metres or greater in length have an average coefficient of friction less than 0.30.
9.4.2.5 Standard − Corrective maintenance action shall be programmed [emphasis added] when: the average coefficient of friction for the entire runway is below 0.60; or any areas of a runway surface that are 100 metres or greater in length have an average coefficient of friction less than 0.50.
The Ottawa International Airport Authority periodically conducts friction tests of all runways through a contractor. This testing is done at least 3 times per year in nonwinter months. The results of the testing provide trend information. The last friction test performed at CYOW before this accident was in April 2010 (Appendix F). The average coefficient of friction for the entire length of Runway 07/25 was 0.55, Footnote 22 and the minimum 100-metre section average was 0.44. These values are the averages of 4 measurements taken at 3 metres along each side of the centreline of the runway. Based on these results, the Airport Authority only planned further friction testing of 07/25 within a period of 2 months. TP312E does not provide a time frame within which corrective maintenance action must be taken. Before the accident, no corrective maintenance action took place. A runway friction test was completed on 25 June 2010. This test revealed an average runway coefficient-of-friction value of 0.63, which was a 14.5% improvement over the April test. The lowest average coefficient of friction for a 100-m section was 0.47. Rubber removal was completed on 21 July 2010. The average coefficient of friction since 2004 for Runway 07/25 and that for Runway 14/32 were compared (Appendix F). Runway 14/32 shows significantly higher friction readings when compared with Runway 07/25. The readings over the past 6 years have been fairly stable for Runway 14/32; however, for Runway 07/25, the friction readings have shown a slow but steady decline over the same period. The investigation determined that many countries use the ICAO-recommended 1.0-mm layer of water when measuring the runway coefficient of friction; Canada uses 0.5 mm. The threshold criteria for taking corrective action to restore runway friction characteristics (Table 4) were developed using a surface-friction tester vehicle with a smooth tire, at a pressure of 210 kPa, travelling at 65 km/h. Table 4 - Threshold criteria for corrective action to restore runway friction, by organization
Threshold criteria Minimum friction values TC Footnote 23
Runway average − corrective action programmed 0.60 0.60 0.60 Runway average − corrective action required 0.50 0.50 0.50 Lowest 100-m average − corrective action programmed 0.40 0.60 0.60 Lowest 100-m average − corrective action required 0.30 0.50 0.50 The Ottawa International Airport Authority conducted monthly friction testing on Runway 07/25 from April to August 2011, using both 0.5-mm and 1.0-mm layers of water. Six different testing sessions were conducted, and the results were provided to the investigation. Based on the minimum friction values for the lowest 100-m average in the above table, immediate corrective action would have been required 5 times out of 6 when using values from the ICAO / Federal Aviation Administration (FAA). However, when using TC criteria, the 2011 results indicated that no corrective action would have to be planned or taken.
1.10.5 Runway surface texture Runway surface texture is considered to be the main factor in the braking friction coefficient of a wet runway. Runway surfaces contain both macrotextures and microtextures (Figure 1 Footnote 27). Figure 2. Runway surface microtexture and macrotexture
Microtexture is the texture of the individual stones and is hardly detectable by eye. It can be felt, but cannot be directly measured, and it is one of the most important factors in reducing the onset of viscous hydroplaning. Footnote 29 Degradation of microtexture, caused by the effects of traffic, rubber deposits, and weathering, may occur within a comparatively short period compared with the time required for degradation of surface macrotexture. Footnote 30
A wet runway is covered with sufficient moisture to cause it to appear reflective, but is not "contaminated" … On a wet runway, the braking friction is reduced compared to that for a dry runway.
Light rain started to fall again approximately 12 minutes before the accident, and the wind was blowing directly across Runway 07 at 10 knots gusting to 16 knots. The runway was not grooved. After the rain started, only 1 aircraft preceded the accident aircraft onto Runway 07. There were no pilot weather reports (PIREPs) related to braking action before the accident. No report on the condition of the runway surface was done after the rain started, nor was one required. Video recordings of the ramp area in the vicinity of the TC hangar and of the area in front of the fire hall showed surfaces that were wet and that appeared shiny or reflective. Considerable spray could be seen from the landing of LOF8050 on Runway 07. Aircraft Rescue and Firefighting (ARFF) personnel noted that the runway at the time of the initial response was wet with puddles in the vicinity of the threshold of Runway 25. 1.10.7 Slippery when wet
All new runways should be designed with uniform transverse profile in accordance with the value of transverse slope recommended in Annex 14 and with a longitudinal profile as nearly level as possible. A cambered transverse section from a centre crown is preferable but if for any reason this cannot be provided then the single runway crossfall should be carefully related to prevailing wet winds to ensure that surface water drainage is not impeded by the wind blowing up the transverse slope. … Particular attention should be paid to the need for good drainage in the touchdown zone since aquaplaning induced at this early stage of the landing, once started, can be sustained by considerably shallower water deposits further along the runway.
The transverse slope on each side of the centreline is not symmetrical; The slope is not substantially the same throughout the length of the runway; and The apex of the runway crown moves left of centreline, reaching the left edge by the end of the runway.
Grooving reduces the potential for both dynamic and viscous hydroplaning, by providing a place (i.e., grooves) for the water to escape from underneath tires. Grooving is applied to both the macrotexture and microtexture of the runway surface. Annex 6 of the ICAO defines a grooved or porous friction course (PFC) Footnote 36runway as "a paved runway that has been prepared with lateral grooving or a porous friction course surface to improve braking characteristics when wet." Footnote 37TP312E states that "the surface of a paved runway shall be so constructed as to provide good friction characteristics when the runway is wet." Footnote 38 However, there is no requirement in Canada that runways be grooved as a means to provide good friction characteristics during wet conditions.
Where such conditions are deemed to exist on a runway surface or portion thereof for excessive periods of time, runway grooving may be considered by the Airport Operator as an option for minimizing surface water depths and reducing the potential for hydroplaning [see Appendix G]. However, surface grooving is not a requirement for new or existing runway pavements in Canada. None of the runways at CYOW are grooved. There are no grooved runways at any major civil airport in Canada.
TC has indicated that runway grooving is not practical in Canada, due to challenges associated with winter maintenance. A limited survey of airports was conducted in areas of the United States where weather conditions similar to the Ottawa area can be expected. Of the 23 airports that were sampled, 18 had grooved runways, 2 had a PFC overlay, and 3 had no surface treatment. The airports included a mix of asphalt runways and concrete runways (Appendix H). In 1997, the FAA published Advisory Circular (AC) 150/5320-12C: Measurement, Construction, and Maintenance of Skid-resistant Airport Pavement Surfaces, which stated the following, in support of pavement grooving: Pavement grooving was the first major step in achieving safer pavement surfaces for aircraft operations in wet weather conditions … a high level of friction could be achieved on wet pavement by forming or cutting closely spaced transverse grooves on the runway surface, which would allow rain water to escape from beneath tires of landing aircraft.
FAA AC 150/5200-30C: Airport Winter Safety and Operations, dated 09 December 2008, states: Grooves cut into the pavement will trap anti-icing/deicing chemicals, reduce loss, and prolong their actions. Grooves also assist in draining melt water and preventing refreezing. There is empirical evidence that grooves and porous friction courses modify the thermal characteristics of a pavement surface, probably by reducing the radiant heat loss, and delay the formation of ice. There do not appear to be any negative effects from grooving pavements.
The wheel-speed transducers generate an alternating-current voltage in proportion to the rotational velocity of the wheels. The signals are fed to the BCU for processing (which includes conversion to linear velocity in knots via the velocity converter) and sent to the FDR. The linear velocity is not used by the BCU to modulate the brake pressures during antiskid operation, but rather is used by the BCU for activation and deactivation of the antiskid function. The aircraft manufacturer indicated that FDR data from other EMB-145 aircraft exhibited the same discrepancy between wheel speed and ground speed, suggesting that the discrepancy was a fleet-wide anomaly. All 4 of the wheel-speed transducers from the occurrence aircraft were subsequently tested by the BCU manufacturer, and all were found to be functioning correctly. The reason for the anomalous wheel-speed data could not be determined. Although the wheel-speed values recorded on the FDR were suspect, the data were still considered useful in assessing wheel-speed trends. Although there is no regulatory requirement to record wheel-speed data, the information can be useful in determining initial wheel spin-up, braking performance, antiskid operation, etc.
For many companies, it is standard practice to carry out testing for drugs and alcohol following any work-related accident. FAR Part 120.109 requires that employers carry out post-accident testing of this type. However, FAR Part 120.123 specifically precludes any collection or testing outside the territory of the United States. Following this accident, the company reviewed its requirements and abilities to conduct drug testing as a matter of standard practice, but decided that it was not empowered to carry out tests, because the pilots were in Canada. Currently, there are no regulations in Canada that require mandatory drug-and-alcohol testing following an aviation occurrence. The available information collected during the course of this investigation did not indicate that drugs or alcohol were used or played any role in this occurrence. 1.14 Fire
When the aircraft came to a stop, the flight attendant initiated the evacuation procedure. The passengers made use of the forward left main-cabin door, the forward right emergency-exit catering door, and both the left and right over-wing emergency exits. The evacuation was quick and orderly, except for several passengers taking their carry-on baggage with them despite repeated shouting to them by the flight attendant of specific instructions to the contrary. This insistence by passengers on retrieving their carry-on baggage is not unique to this accident, as identified in the TSB Recommendation on carry-on-baggage (A07-07). Footnote 39 Any delay in evacuation during an emergency can present a significant risk to the safety of passengers.
The passengers were directed to one central location away from the aircraft until help arrived. Within 3 minutes after the aircraft came to a stop, the ARFF units arrived on scene. There were only minor injuries, which were sustained by both pilots and 1 passenger. The first officer, whose leg was pinned between the rudder pedals and the bottom of the instrument panel, initially had some difficulty evacuating the right seat in the cockpit. 1.15.2 Aircraft rescue and firefighting
The CYOW Authority maintains a Category 8 ARFF response capability (Table 5). Table 5 - ARFF response capabilities provided under aircraft category 8
Aircraft category Overall aircraft length
At least 49 m but less than 61 m
The ARFF unit received the alarm, which was initiated by the control tower, at 1430:46. By the time the 4 ARFF vehicles arrived at the scene, all of the passengers were out of the aircraft and grouped together near the right front of the aircraft. A temporary shelter was erected to shield passengers from the rain. The captain, the first officer, and 1 passenger were treated for minor injuries. A request was made for bus transportation and a paramedic unit to transport the injured to hospital. Three ARFF vehicles were released at 1745; the last one stayed behind to provide fire protection for the remaining on-site personnel. 1.16 Tests and research
Resort Air was founded in 1982 and changed its name in 1989 to Trans States Airlines LLC, with its corporate headquarters located in St. Louis, Missouri. Originally operating various types of turboprop aircraft, TSA started operating the Embraer EMB-145 in 1998, and has a fleet of approximately 28 aircraft. TSA is a FAR Part 121, regional feeder airline that conducts flights for United Airlines and US Airways to approximately 39 destinations. Training and Use of Flap by Trans States Airlines LLC TSA 's initial new-hire training program consists of 61 hours of non−aircraft-specific training;
138 hours of aircraft-specific ground training; and 57 hours of aircraft-specific flight training.
Aircraft performance on wet and contaminated runways is addressed in the general aircraft-performance modules for both initial and recurrent training. Flight crews are also exposed to aircraft-performance charts, found in TSA 's Flight Operations Training Manual, Volume 1. Also discussed in the training curriculum is hydroplaning as it pertains to performance considerations on take-off and landing on contaminated runways. Night landings on contaminated runways are listed as an element of TSA 's initial simulator training program. Training in relation to operations on grooved and ungrooved runways, or in relation to the fact that Canada lacks grooved runways, is not specifically addressed in the training curriculum. TSA does not do specific company line checks on the flight crews that are flying into Canada. The flap-selector lever on all TSA EMB-145 aircraft provides 4 detent settings, which are at 0°, 9°, 22°, and 45° positions, respectively. Intermediate positions cannot be selected. Flaps increase lift, resulting in lower stalling speed and permitting lower touchdown speed. They also increase drag, permitting a steeper approach without increasing airspeed. The extra drag results in a shorter landing roll. The greater the flap setting, the lower the speed for landing. When TSA began operating the Embraer EMB-145 in 1998, crews were trained to use a flaps setting of 45°, unless a flaps-22 setting were called for to meet specific performance requirements or as required in an emergency. At the time of the occurrence, TSA Standard Operating Procedures (SOP) indicated that flaps 22 was the preferred flap setting for landing. It allowed for a wider speed range, thus reducing the likelihood of exceeding the maximum flap speed. Also, a reduced flap setting creates less drag, resulting in less thrust being used with a commensurate decrease in fuel consumption. Use of a flaps-45 setting was still encouraged in situations where
braking action was degraded; there was standing water on the runway; or the runway was not grooved and was wet.
TSA SOP (Section 1, page 33, paragraph 4.2 – Landings), states in part: The key factor for a successful landing is a stabilized approach and proper thrust/flare coordination. At an average weight and VREF, the aircraft is traveling down the runway at over 150 feet per second while in the flare. Long flare times can lead to a touchdown outside the touchdown zone (TDZ) and/or subsequent hard braking.
The Flight Safety Foundation, in its study on approach-and-landing accidents, found that a 5% increase in final-approach speed increases the landing distance by 10% if a normal flare and touchdown are conducted with deceleration of the aircraft on the ground. Footnote 44 The study also found that extending the flare and allowing the aircraft to float and bleed off excess airspeed can also increase the landing distance, because the excess speed must be bled off in the transition from the threshold crossing to the touchdown. This measure typically uses 3 times more runway than decelerating on the ground. Footnote 45
Since it is difficult to land at lower speeds than the NASA Footnote 46 critical speed Footnote 47, it is necessary that certain landing techniques be used to minimize the hydroplaning effects, namely:
Retract the flaps right after touchdown to place more of the airplane's weight on the tires. Go to an alternate airport if conditions point to a serious likelihood of hydroplaning. A stabilized approach is of vital importance. Be aware that landings on a runway contaminated with water, ice, snow, etc., will imply an increase in the necessary distance for a safe landing, with the values being from 40 to 100% above the normal distance.
Dynamic and viscous hydroplaning Footnote 48 are described as follows: Dynamic hydroplaning is caused by the buildup of hydrodynamic pressure at the tire-pavement contact area. The pressure creates an upward force that effectively lifts the tire off the surface. When complete separation of the tire and pavement occurs, the condition is called total dynamic hydroplaning, and wheel rotation will stop. … Total dynamic hydroplaning usually does not occur unless a severe rain shower is in progress. There must be a minimum water depth present on the runway to support the tire. The exact depth cannot be predicted since other factors, such as runway smoothness and tire tread, influence dynamic hydroplaning. Both smooth runway surface and smooth tread tires will induce hydroplaning with lower water depths. While the exact depth of water required for hydroplaning has not been accurately determined, a conservative estimate for an average runway is that water depths in excess of 0.1 inch (2.54 mm) may induce full hydroplaning.
Reverted-rubber hydroplanning Footnote 49 is described as follows:
Reverted rubber hydroplaning occurs when a locked tire skids along the runway surface generating sufficient heat to change water into steam and revert (melt) the tire rubber to its original uncured state. Only this type of hydroplaning produces a clear mark on the tire tread in the form of a burn; a patch of reverted rubber. This type of hydroplaning is also known to produce steam-cleaned marks on the runway due to the steam cleaning effect of the water vapor between the tire and the runway surface. A review of literature on aircraft-tire hydroplaning shows that, while reverted-rubber
hydroplaning is usually accompanied by steam-cleaned marks on a runway, the opposite is not necessarily true. That is, steam-cleaned marks are not direct evidence of this type of hydroplaning, and occurrences have been reported where steam-cleaned marks were observed on runways, but there were no reverted-rubber burns on the tires. Footnote 50 This phenomenon could be explained by the temperature difference between water steam formation and tire reversion. At normal atmospheric pressure, water boils at 100°C. The rubber-reversion temperature, however, is about 204° to 316° C. Footnote 51 Thus, there is a temperature range in which steam could form under the tire and clean the runway, but the tire rubber would not be melted. Steam-cleaned marks were observed on the runway, as indicated by the photographs taken shortly after the occurrence (Photo 2).
Photo 2. Steam-cleaned marks observed on the departure end of Runway 07
1.18.6 Other occurrences involving CYOW Runway 07/25 Since 2000, there have been 3 other overruns of Runway 07/25 when the runway was wet or contaminated (Appendix J). As per Appendix F, friction-test results for Runway 07/25 have been inferior to those for Runway 14/32 since 2004. Because of those 3 overruns, TSB decided to look more closely at the runway's construction and maintenance.
2.1 Introduction It is widely acknowledged that a wet runway may be slippery and require additional landing distance over and above that required for a dry runway. National and international efforts to closely correlate surface-friction measurements on wet runways to aircraft braking effectiveness have not been successful.
The brake system of the occurrence aircraft performed as designed. The action of the braking system during the occurrence ground roll is consistent with the aircraft encountering poor braking conditions. The aircraft deceleration was low due to the lack of braking force caused by viscous hydroplaning. The aircrew sensed this low deceleration, and attempted to increase it by applying maximum brakes. The antiskid system, however, reacted to the low coefficient of friction by reducing brake pressure to prevent the wheels from locking up and the aircraft from skidding. Embraer's performance calculations were based on the coefficient of friction included in United States Federal Aviation Regulations (FAR) 25.109(c)(1), and gave a significantly shorter landing distance than that of the occurrence aircraft. Both the occurrence landing and the Honeywell actual landing test data exhibited a significantly lower braking coefficient of friction than that predicted by the smooth wet runway equations in FAR 25.109(c)(1). These results are consistent with the findings of the National Transportation Safety Board (NTSB) for similar landing-related occurrences.
During the approach, the wind veered from 100° at 8 knots to 160° at 10 knots gusting to 16 knots. The crew was offered a choice to continue for Runway 07 or proceed for Runway 14. For a variety of reasons, the crew elected to continue the approach for Runway 07. The airport analysis data charts provided in the flight release package supported this decision, as the conditions were within the aircraft's performance criteria. Trans States Airlines (TSA) Standard Operating Procedures (SOP) provide the criteria for a stabilized approach and the conditions that would necessitate execution of a missed approach. As per the SOP, the crew selected a VREF of 131 knots indicated airspeed (KIAS). For a flaps-22 landing, the minimum wind correction is 5 KIAS, and the maximum is 20 KIAS (Appendix D). The crew mistakenly added the minimum wind correction of 5 KIAS to their VAPP instead of adding the headwind component, which in this case was zero. The crew then added 6 knots (gust factor) for a VAPP of 142 KIAS. The crew added another 4 KIAS to compensate for the gusty conditions, which resulted in 146 KIAS (131+5+6+4), or 9 knots above what is specified in the SOP. This extra speed had to be managed by the crew in order to cross the runway threshold at the planned VREF speed of 131 KIAS. The aircraft crossed the threshold at 139 KIAS, or 8 knots faster than that calculated for the landing weight of the aircraft. The SOP required crews to initiate a missed approach when the target airspeed was exceeded by plus or minus 5 knots. It is likely that the crew did not consider the situation to warrant an overshoot; the crew believed that the entire approach was stabilized and the runway was in sight. A 5% increase in final approach speed increases the landing distance by 10% if a normal flare and touchdown are conducted with deceleration of the aircraft on the ground. Extending the flare and allowing the aircraft to float and bleed off excess airspeed typically uses 3 times more runway length than decelerating on the ground. The aircraft landed long and touched down 2270 feet beyond the threshold, albeit within the first third of the available landing distance. The Embraer landing performance analysis determined that, even with the higher speed and long touchdown, the airplane should have been able to stop 1800 feet before the end of the runway.
Thrust reversers have been shown to play a significant role in reducing accelerate-stop distances on wet and contaminated runways, and provide a stopping force that is not dependent on runway friction. When landing on a runway with poor braking action, the effect of reverse thrust can make a dramatic difference. Footnote 56 In this particular occurrence, the aircraft's braking coefficient of friction was very low throughout the landing roll, and did not start to increase until the aircraft had slowed to approximately 90 KIAS. Had the aircraft been equipped with thrust reversers, the application of reverse thrust as soon as possible after touchdown would have permitted the aircraft to slow down below hydroplaning speed much sooner, and possibly prevented an overrun.
The depth of water on the runway was not determined; however, automatic rainfall measurements taken at the time indicated that approximately 2 mm of rain had fallen in the 12 minutes before the accident. The predominant direction of wind during rainfall, together with a runway crown that shifts progressively more to the left side for the last 6000 feet of Runway 07, may have resulted in a more water on the runway than expected. The flight data recorder (FDR) data for LOF8050 showed that the main landing-gear wheels, although slower than normal to spin up, did continue to turn throughout the landing roll. Hydroplaning occurring on a wet runway can be due to various factors, including:
the presence of any standing water due to inadequate drainage; the slope of the runway surface; the macrotexture and microtexture of the runway surface; the friction coefficient of the surface. In this particular occurrence, the factors exhibited during the landing roll are indicative of viscous and not dynamic hydroplaning. These factors were smooth touchdown, slower-than-normal wheel spin-up with no lockup, and supply of very low brake pressures by the brake control unit (BCU) until very low speeds. The friction between the tire and runway was reduced, but not to a level that impeded the wheel rotation. Dynamic hydroplaning did not occur, as wheel rotation did not stop, and the water depth was calculated to be less than the 3 mm normally associated with the onset of dynamic hydroplaning. Once hydroplaning begins, it will continue to speeds well below that required to initiate hydroplaning. Although the pedals of both pilots were deflected to the right during the latter part of the landing roll, the aircraft veered to the left, indicating the lack of friction and lack of directional control that are associated with hydroplaning. During a post-accident examination, no reverted-rubber burns were found on the aircraft's main landing-gear tires. The aircraft exited the runway before the rubber reached reversion temperature; hence there was no reverted-rubber hydroplaning. However, there were steam-cleaned marks at the end of the runway, indicating the temperature had reached that at which steam is formed.
1.7 Fatigue Sleep-wake histories for the captain and the first officer were analysed; when precise times of sleeping and waking could not be determined, conservative estimates were used.
On the night immediately preceding the occurrence, the captain slept 2 to 3 hours less than normally. Given that the captain's normal period of sleep was below the minimum average requirement, and that his most recent sleep period was even less, the captain was likely fatigued at the time of the occurrence. The first officer was a light sleeper who experienced poor-quality sleep, with 2 awakenings per night. The sleep environments required by the schedule and the shortened sleep periods, combined with the poorer overall quality of the first officer's light sleep, resulted in the first officer likely being fatigued at the time of the occurrence.
Both the International Civil Aviation Organization (ICAO) and Transport Canada (TC) have set standards and recommended practices so that runways are designed to provide good friction characteristics when wet. Factors that affect the runway coefficient of friction include longitudinal/transverse slopes, macrotexture and microtexture. In the event of a runway excursion, the surfaces adjacent to the runway should be constructed to minimize aircraft damage. Runway surface-condition reporting must also be accurate, timely, and disseminated to those who can best use the information in making the decision whether or not to land. 1.8.2 Runway characteristics
2.8.3 Runway surface condition Effective maintenance of a runway surface is critical to retaining maximum friction characteristics. Periodic friction measurement, using a continuous friction-measuring device with a self-wetting capability, indicates if the surface is becoming more slippery when wet. This indication allows the airport to plan maintenance action, such as rubber removal, to re-establish runway friction levels. Combined with accurate data on the runway surface profile, the friction reading would also give airport authorities an indication of whether a runway should be considered slippery when wet, so that the appropriate notice to airmen (NOTAM) information can be disseminated. Company operations personnel, including aircrew, could then be forewarned that appropriate landing techniques should be used to reduce the likelihood of hydroplaning.
For aircrew to make a proper assessment of landing conditions, they should be made aware of the amount of water on the runway surface. Video recordings taken at the time of the accident revealed considerable water spray from the landing aircraft. TP312E does not provide guidance material on how to assess the runway surface condition to determine the amount of water on the runway. During nonwinter months, there is no policy at CYOW that requires inspection of the runway surface when rain starts, or that requires periodic inspection while rain is falling. 2.8.4 Runway grooving One of the methods adopted worldwide to enhance water drainage from a runway has been to groove the runway surface. Studies have shown that water drains much more rapidly from a grooved runway, to the extent that the runway appears damp even while rain is still falling. The runway therefore retains a higher friction level, resulting in better braking action. Grooved runways improve drainage and skid resistance, reduce the risk of hydroplaning, and are recommended by the FAA. Studies have shown that wet, grooved runways often provide a level of braking only marginally lower than dry runways provide. A limited survey of mid-sized to large US airports with climates similar to that of CYOW shows that the majority have grooved runways. This indicates that a cold climate is not a limiting factor when deciding to groove a runway. Runway grooving has been shown to maintain higher friction levels in wet conditions. The lack of standards or recommended practices in Canada requiring friction enhancement, such as runway grooving, increases the risk of runway overruns on wet runways as a result of hydroplaning. Although the TC study makes common reference to both grooved and porous friction course (PFC) runways, it does not differentiate between the two. The FAA and Eurocontrol Footnote 57 recommend that PFC overlays not be constructed on airport runways that have high aircraft traffic operations, because of the difficulty of removing rubber deposits without replacing the surface course altogether. 2.8.5 Rain measurement The weather observers at CYOW do not have a remote rainfall-measuring device available to them. The intensity of rainfall is a qualitative measure, determined in accordance with the Environment Canada Manual of Surface Weather Observations (EC MANOBS). Based on information obtained from the City of Ottawa Stormwater Unit measuring equipment located at the airport, the rate of rainfall was equivalent to a moderate level using the criteria in EC MANOBS. This information might have been useful to the crew of LOF8050 in deciding whether or not to continue the approach or select another available runway.
The value of a runway having adequate transverse slope to facilitate the rapid drainage of water is clearly recognized in TP312E. In fact, both ICAO and TC have set standards and recommended practices so that runways are designed "… to provide good friction characteristics when the runway is wet." Footnote 58 The transverse and longitudinal slope of the runway must be designed to provide rapid drainage of water during rainfall periods. The profile of the crown of Runway 07, combined with a strong 90° crosswind from the right, would have impeded the rate at which water would have drained from the surface of the runway. This impediment would have potentially made the runway surface more slippery during rainfall.
Since being resurfaced in 1994, Runway 07/25 at CYOW does not meet the minimum recommended practice for amount of transverse slope and positioning of the crown in relation to the centreline. 2.8.7 Runway end safety area The aircraft overran the runway threshold and the runway strip. It subsequently encountered a significant dip, where the nose landing gear folded rearward, resulting in substantial damage to the nose of the aircraft.
3.1 Findings as to causes and contributing factors The crew calculated an inaccurate VAPP (i.e., target approach speed), and flew the approach faster than recommended.
Rainwater accumulated on Runway 07/25 due to the crosswind and the design of its transverse slope, resulting in a further decline in the coefficient of friction for the occurrence flight. The crew did not select flaps 45, as encouraged by Trans States Airlines standard operating procedures for landing on a wet, ungrooved runway, which resulted in a higher landing speed and a longer landing distance.
The aircraft overran the runway threshold and the runway strip, and subsequently encountered a significant dip, where the nose landing gear folded rearward, resulting in substantial damage to the nose of the aircraft. 3.2 Findings as to risk In the absence of information and training about ungrooved runways, there is a risk that crews will not carry out the appropriate landing techniques when these runways are wet.
The published minimum friction values of Transport Canada are lower than, and its testing methodology is different from, the minimum friction values and testing methodology of the International Civil Aviation Organization / Federal Aviation Administration. These differences may result in reduced runway friction levels at Canadian airports. The lack of standards or recommended practices in Canada requiring friction enhancement, such as runway grooving, increases the risk of runway overruns on wet runways.
Lack of thrust reversers increases the risk of runway overruns when landing on wet runways. The coefficient of friction values included in United States Federal Aviation Regulations Section 25.109(c)(1) give a significantly shorter landing distance than that of the occurrence aircraft and in other occurrences investigated by the National Transportation Safety Board. This discrepancy increases the risk of runway overruns on wet runways.
3.3 Other findings Due to the absence of a device that continuously measures and reports the amount of rainfall, the rain intensity at Ottawa/MacDonald-Cartier International Airport is determined by subjective means. Therefore, the reported amount or intensity of rain may be different from what crews actually encounter on landing.
4.1 Safety action Taken 4.1.1 Trans states Airlines
Effective Immediately: Normal landing flap setting is 45 degrees.
Environment Canada has published Manual of Surface Weather Observations (MANOBS) 7th edition, Amendment 18, effective January 2013. MANOBS Section 10.3.5.6(c) has been amended to require reporting of changes in precipitation intensity criteria for issuing a SPECI (e.g., LGT [light] to MDT [moderate] or HVY [heavy]; MDT or HVY to LGT; MDT to HVY; or HVY to MDT). 4.1.7 Transport Canada Transport Canada has published Advisory Circular no. 300-008: Runway Grooving, effective 8 April 2013. The purpose of the document is to provide information and guidance regarding the grooving of runway pavements.
Appendix A – List of TSB laboratory reports The following reports were produced by the TSB Laboratory:
LP086/2010 − FDR Analysis
LP102/2010 − Maintenance Records Review
LP103/2010 − Site Survey
LP104/2010 − Examination Main Landing Gear Tires
LP105/2010 − Brake System Analysis
LP106/2010 − Braking Performance Analysis
Appendix B – Sequence of events (LOF8050) from 1430:07 to 1430:59 Appendix B – Sequence of events (LOF8050) from 1430:07 to 1430:59
Appendix C – Intensity of rainfall As specified in Environment Canada Manual of Observations (EC MANOBS) Section 3.9.5, when the intensity of rain, rain showers or freezing rain must be determined without the aid of instrument measurements, the following table may be used as a guide:
(rain in sheets) Spray over hard surface
Hardly any Noticeable Heavy to a height of several centimetres Puddles
Form slowly Form rapidly Form very rapidly Source: EC MANOBS
Appendix E– Runway end safety area TSB Recommendation A07-06:
Runway strip 60 m + RESA 240 m = 300 m ICAO Recommended Practice:
ICAO Standard: Runway strip 60 m + RESA 90 m = 150 m
Appendix F – CYOW Runway friction testing values Appendix F – CYOW Runway friction testing values
Appendix G – Grooved runway Appendix H− Sample Northern US Airports: Runway construction Sample Northern US Airports: Runway construction
Runway surface type Runway surface treatment Number of runways
St. Paul/Holman Field
Syracuse/Hancock
Ted Stevens/Anchorage
Grand Rapids/Itasca
Appendix J – Other CYOW Runway 07/25 Occurrences A00H0004, 15 September 2000
European Action Plan for the Prevention of Runway Excursions, Edition 1.0 (January 2013), Appendix E: Aircraft Operators.
Full brake pressure is normally reached when the brake pedals are depressed to 95% of maximum pedal travel. There is a dead band between 95% and 100% of pedal travel, where the brake pressure remains unchanged.
The term “g” refers tothe unit of measure used for local acceleration due to gravity.
NAV CANADA, Air Traffic Control Manual of Operations (MANOPS), 124.1.D Return to footnote 9 referrer
Environment Canada, Manual of Surface Weather Observations (EC MANOBS), 10.3.7, Accident check observation: “Immediately upon learning of an aircraft accident, at or in the vicinity of the weather observing station, the observer shall make an accident check observation unless a complete observation has been made subsequent to the accident.”.
International Civil Aviation Organization (ICAO), Annex 3, Amendment 75: Meteorological Service for International Air Navigation(as cited by Canadian Aviation Regulations [CARs], 804.01[ a])
Runway reference code numbers and letters are defined in Transport Canada, Aerodromes Standards and Recommended Practices (TP312E) 4th edition (1993, revised 03/2005), Chapter 1, Section 1.3. Reference codes identify the length of the runway, as well as the maximum wing span and outside wheel span for aircraft.
Transport Canada, Aerodromes Standards and Recommended Practices (TP312E) 4th edition (1993, revised 03/2005). TP312E serves as the authoritative document for Canadian aerodrome specifications, and is intended to fulfill Canada’s obligations under ICAO Annex 14 to the Convention on International Civil Aviation.
A rating of Satisfactory in Part is assigned if the planned action or the action taken will reduce but not substantially reduce or eliminate the deficiency. Return to footnote 19 referrer
Runway friction values are recorded on a scale from 0 to 100, whereas the runway coefficient-of-friction scale is from 0.0 to 1.0 (e.g., a runway friction value of 50 equates to a coefficient of friction of 0.50).
ICAO, Airport Services Manual,Part 2: Runway Surface Conditions, DOC 9137, Section 2.3
A. Ranganathan, Wet Runway Overruns: Pilot Error? System Deficiency?, presented to International Society of Air Safety Investigators (ISASI) Forum (January to March 2006) Return to footnote 32 referrer
ICAO Aerodrome Design Manual (1983) 2nd edition, DOC 9157-AN/901, Part 3, Section 5.2.6.2: Slopes
The Eurocontrol SKYbrary article Runway Surface Friction describes PFC as “an alternative to grooving as a means of facilitating surface water dispersal …” which “… allows water to pass vertically through the surface layer and then move horizontally clear of the runway …”
VAPP is the target approach speed.
VREF is the speed at which the aircraft should cross the threshold of a runway at 50 feet agl.
Eurocontrol is a civil-military organization that provides support to air traffic operations across Europe. Return to footnote 57 referrer