135 landing distance

[temcgrew]

If on a 135 flight to an airport with two (seperate) runways, one meeting the 60% rule and one that doesnt' but does meet the performance needs of the aircraft, the aircraft in front of you has a misshap and closes the runway. Can you legaly land on the other runway even though it does not meet the 60% rule?

My answer is yes of course becouse the 60% rule is for planning. I have heard a different viewpoint recently and would like some clarification.

 

[MetroSheriff]

If on a 135 flight to an airport with two (seperate) runways, one meeting the 60% rule and one that doesnt' but does meet the performance needs of the aircraft, the aircraft in front of you has a misshap and closes the runway. Can you legaly land on the other runway even though it does not meet the 60% rule?

My answer is yes of course becouse the 60% rule is for planning. I have heard a different viewpoint recently and would like some clarification.

UJ,

Yes, you can legally land on the runway. The 60% is for dispatch purposes only. I will post the references in a bit.

 

[Kroll]

If you guys are refering to 135.385. I don't read it this way and don't know a lot pilots that do. Please post something to correct me.

I just had a pilot that I was flying with tell me the exact situation you explained in the first post. Two runways wind was a 6 knot crosswind on the longer runway. Atis favored the shorter runway that met 91 numbers. I chose to land on the longer runway. ( Met 135 numbers, longer by 2000', crosswind would have been about 3 kts if caculated.) I think if you went off the end of the part 91 rwy the Feds would get you.

Let me explain my veiw of 135.385:

My understand the 60% rule is to protect the commercial flying public from you. Yes it's part of planning process but I believe you must land with those numbers too. You can use the 91 numbers to for an emergency and to dispatch to that destination airport if condition are not favorable.

Example: Lets say I'm flying a jet to PWK clear day. One long rwy that meets 135 numbers, none of the other runways meet 91 number so I have one runway to use. The wind is a direct crosswind that exceeds aircraft performance (so it is not suitable) I can not dispatch.

Example 2: Now I'm flying to DPA. Rwy 2L meets 135 number, and 28 meets part 91 numbers. However there is this wind out of the west that makes 2L not legal to land. Rwy 28 will be suitable but only part 91. Now in part (E) it allows me to dispatch with a alternate airport that meets 135 numbers. So now I take off. When I get to DPA and 2L is suitable then I can land on it. If it is still not suitable then I can not land on 28 I must head to my suitable alternate. I don't believe you can land on 28 because it is suitable with part 91 numbers.

I don't believe the 135 landing distances can be wavied unless you have an emergency. I'm still looking into this so please post any info you have that says the contrary. I've asked a lot of guys I respect and they agree with me on this. I plan on asking my POI so I will get back with what he says.

 

[TransMach]

FAR 135 Landing Distance, 135.385

I posted this earlier in another forum asking, essentially, the same question. Answer: no, you don't need "factored" landing distance on the runway you actually land on.

Here's the guidance lifted from the Aviation Safety Inspector's (Operations) Handbook.

LANDING FIELD LENGTH REQUIREMENTS

FAA Order 8400.10, CHG 5, (6/30/91) Volume IV, Chapter 3, Section I – Airplane Performance Computation Rules

/S/ 909 SMALL AIRPLANE CERTIFICATION.

E. Application of Flight Handbook Performance Limits. Many of the requirements of Subparts I of part 121 and Part 135 apply only until the aircraft takes off from the departure point. Other requirements from these Subparts apply at all times as do the AFM limitations. For example, FAR 121.195 and FAR 135.385 prohibit a large, turbine airplane from takeoff unless, allowing for en route fuel burn, the airplane will be capable of landing on 60% of the available runway at the planned destination. The regulations do not, however, prohibit the airplane from landing at the destination when, upon arrival, conditions have changed and more than 60% of the runway is required. In this case, the airplane must only be able to land on the effective runway length as shown in the flight manual performance data.

/S/ 921. WATER AND CONTAMINATION OF RUNWAYS. AFM performance data is based on a dry runway. When a runway is contaminated by water, snow, or ice, charter AFM performance values will not be obtained. Manufacturers typically provide guidance material to operators so that appropriate corrections for these conditions may be applied to performance calculations. Inspectors should be aware of the following guidance concerning these conditions.

A. Any runway which is not dry is considered to be wet. Standing water, puddles, or continuous rain are not necessary for a runway to be considered wet. Runway braking friction can change when there is a light drizzle. In some cases, even dew or frost which changes the color or a runway will result in a significant change in runway friction. The wet-to-dry stopping distance ratio on a well-maintained, grooved, wet runway is usually around 1.15 to 1. On a runway where the grooves are not maintained and rubber deposits are heavy, the stopping distance ratio could be as high as 1.9 to 1. On un-grooved runways, the stopping distance ratio is usually about 2 to 1. In the case of a runway with new pavement or where rubber deposits are present, the ration could be as high as 4 to 1. Some newly-surfaced asphalt runway surfaces can be extremely slippery when only slightly wet.

/S/ 933. LANDING DISTANCE. The maximum weight for an airplane landing on any runway must be limited so that the landing distance required by the performance rules will be less than the effective landing length available.

A. Effective Landing Runway Length. Effective landing runway lenght for all categories of airplanes is the distance from the point on the approach end of the runway at which the obstruction plane intersects the runway to the roll-out end of the runway. [read as “Threshold”, not glide slope intersect, ed.] The obstruction plane is a plane that is tangent to the controlling obstruction in the obstruction clearance area that slopes down toward the runway at a 1:20 slope from the horizontal. The area in which the obstruction clearance plane must clear all obstacles is 200 feet on each side of the runway centerline at the touchdown point, which expands to a width of 500 feet on each side at a point 1.500 feet from the touchdown end and beyond. The centerline of the obstruction clearance area may curve at a radius of not less than 4,000 feet, but the last 1,500 feet to the touchdown point must be straight in. Stopways are not usually considered, and clearways may not be considered, as available landing areas.

Regards,

TransMach

 

[Stealthh21]

The regulations do not, however, prohibit the airplane from landing at the destination when, upon arrival, conditions have changed and more than 60% of the runway is required. In this case, the airplane must only be able to land on the effective runway length as shown in the flight manual performance data.

The key part in that whole thing.

 

[Choppy]

one more question

What runway numbers do you have to use? Do you use the full runway length or do you have to use the actual landing distance? IE: the runway is 5600ft but because of clearways or stopways the effective landing distance on your charts is 4800. What number do you use?