Required runway length?

[dlrk]

I understand that the FMS generates real-time performance data in-flight. But how can I determine if an airport I'm planning a flight to can handle the Challenger without actually flying there and putting it in the FMS?

[Graeme_77]

You don't actually need to fly there, you can load it into the FMS at any point and calculate it. Calculating potential departure performance would be a useful use of cruise time. Just type in the runway length, temperature etc and you can grab the data via the FMS.

[Stevens]

In the FMS you have ALD (Actual Landing Distance) which is factored x 1.00.

The Required Landing Distance (RLD) is for planning purposes. 
The factor you have to enter in the FMS is 1.67. 

Hope that helps. 

[Graeme_77]

Or put “L” into the ALD box to change it to LFL, as explained in the FMS Primer doc.

[FYG001]

Indeed, planning requires a factor of 1.67 in dry conditions, and 1.92 in wet conditions. Once enroute you use LDTA with the RCAM

[richjb]

On 3/21/2022 at 4:23 PM, FYG001 said:

Indeed, planning requires a factor of 1.67 in dry conditions, and 1.92 in wet conditions. Once enroute you use LDTA with the RCAM

Thank you for pointing out the LDTA and RCAM.  I don't have one for the CL650 but do have one for the CL605  See below.  This is the Operational Landing Distance data for use with the reported Runway Condition Codes (RwyCC).  At the end of the document, there are factors for each RwyCC that can be entered into the FMS APPRAOCH REF 2/4 page in the LAND FACT field.  Make sure that you're default is to actual landing distance (ALD) and not factored landing distance when applying the OLD factor.  

Rich Boll

 

Operational Landing Distance (OLD) CL605.pdf

[richjb]

On 1/8/2022 at 6:22 PM, dlrk said:

I understand that the FMS generates real-time performance data in-flight. But how can I determine if an airport I'm planning a flight to can handle the Challenger without actually flying there and putting it in the FMS?

Depend on the operator and what they have available.  Many operators use a flight planning service that also contracts with a performance engineering service provider.  For the business aviation fleet, that is usually Aircraft Performance Group: Aircraft Performance Group: APG (flyapg.com)

APG provides the airline-style airport runway analysis.  If you're familiar with TOPCAT (FlightSimSoft.com), it is the same thing.  You would simply run a landing analysis report for the airport of intended use and then see if the maximum landing weight meets your requirements.  In the US, for part 135 or 91K operators, their minimum field length is normally based on actual landing distance allowing the aircraft to stop within 60% of the runway's declared landing distance available.  This minimum field length is increased by 15% if the runway is forecast to be slippery or wet at the ETA.  Some operators can reduce the runway required to where the actual landing distance will bring the aircraft to a stop within 80% of runway's LDA.  With EASA, they do not permit this type of reduction...yet.  Last I heard, they are looking at it. 

On the QRH for the CL650, for different pressure altitudes there is a chart that provide the "LFL" or Landing Field Length both for a dry runway and a wet runway for each weight at a given pressure altitude.  Since LFL "assumes" standard temperature, there are no corrections provided for temperature.  The chart for a given pressure altitude also give the actual landing distance (ALD) at various landing weights and temperatures.  These QRH chars can be used if you do not have access to an airport runway analysis service. 

One more thing to consider is the landing climb requirement and approach climb requirement.  Landing climb requires a minimum 3.4% climb gradient, 8 seconds after go around thrust is selected, with the aircraft in the full landing configuration.  Most turbojets, this requirement is not limiting.  The other requirement is the approach climb requirement, which requires a 2.1% climb gradient at maximum go around thrust with one engine inoperative, in the approach configuration for a go-around, and with the landing gear retracted.  This a "spot" or snapshot performance requirement at the start of the OEI go around.  On the QRH charts, I noticed that ALD data is not provided above certain temperatures at certain higher pressure altitudes.  Most likely reason is that the aircraft does not meet the approach climb requirement at those pressure altitudes and temperatures.  A closer look at the performance charts in the AFM would likely confirm. 

If you would like a good primer on transport airplane performance, may I refer you to the NBAA website that host the FAA TAPP WG performance videos: Aircraft Climb Performance Videos | NBAA - National Business Aviation Association

They're also available on YouTube from the FAA. Here's the first of four:

Thanks,

Rich Boll

 

[FYG001]

Excellent post Rich, as always.

The CL650 OLD data is exactly the same as for the CL605. I have attached it below.
Intyerestingly, you are better off using the OLD data than the factored ALD data.

I can also fill you in on EASA and the 80 pct. EASA allows since August of last year what they call 'Reduced Required Landing Distances RRLD'. The conditions to go for it are pretty stiff: limieted designated airports, training for that airport, flight data monitoring on landing distances etc. I know of one EASA bizjet operator who has obtained CAA operational approval for it. 

Approach and Landing Data.pdf

Edited April 4, 2022 by FYG001

[richjb]

On 4/4/2022 at 5:11 AM, FYG001 said:

Excellent post Rich, as always.

The CL650 OLD data is exactly the same as for the CL605. I have attached it below.
Intyerestingly, you are better off using the OLD data than the factored ALD data.

I can also fill you in on EASA and the 80 pct. EASA allows since August of last year what they call 'Reduced Required Landing Distances RRLD'. The conditions to go for it are pretty stiff: limieted designated airports, training for that airport, flight data monitoring on landing distances etc. I know of one EASA bizjet operator who has obtained CAA operational approval for it. 

Approach and Landing Data.pdf 178.04 kB · 2 downloads

Thanks sir!

I was not aware that EASA pulled the trigger on the 80% option.  Good to know.  I do know from my FAA performance engineering contact, who retired at the beginning of the year, that FAA and EASA are working to harmonize these rules and regulations, both for airplane certification and operations, including on wet and contaminated runways. More changes in the offing, but I'll be retired by them! :-) 

Thanks for the CL650 OLD data!

Rich 

[richjb]

On 4/4/2022 at 5:11 AM, FYG001 said:

Excellent post Rich, as always.

The CL650 OLD data is exactly the same as for the CL605. I have attached it below.
Intyerestingly, you are better off using the OLD data than the factored ALD data.

 

Approach and Landing Data.pdf 178.04 kB · 2 downloads

 

I am hearing rumors that some operators are applying the 60% or 80% factor to the OLD Data for dispatch.  Ouch!  That's not how that works.  Still peeling the onion back on this one.

Rich 

[FYG001]

I'll try to give a quick simplified overview of the required Landing Distances, so...

DISPATCH phase (before the aircraft is in flight)

DRY = ALD  x 1.67
WET = ALD x 1.92

IN FLIGHT (LDTA - Landing Distance at Time of Arrival)

DRY = OLD data from QRH with RCC code 6 (see added file)
WET = OLD data from QRH with RCC code 5 (see added file)

OR

DRY = ALD x 1.48
WET= ALD x 2.03

The latter is clearly more penalizing but is easier to figure out ;-)
 

Approach and Landing Data.pdf