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## Landing Distance chart figure 4

• jukzizy
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• Away
• Posts: 154

### jukzizy created the topic: Landing Distance chart figure 4

Given the following information:
Pressure height: 3800 Ft
Slope: 1.6% Down To NE
RWY- 04/22
W/V- 040*M/18kts
Find the landing distance required: I got 595 metres..
Please sir can you check and confirm if I'm right?
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• John.Heddles
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• ATPL/consulting aero engineer
• Posts: 454

### John.Heddles replied the topic: Landing Distance chart figure 4

(a) be very careful with interpolation for intermediate values

(b) you might like to double check the slope entry ?

Perhaps you might like to redo the exercise and repost the revised solution for us to review ?

Engineering specialist in aircraft performance and weight control.

• jukzizy
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• Posts: 154

### jukzizy replied the topic: Landing Distance chart figure 4

yes sir..because i'm not sure if I'm doing it right..That's why I want you to cross check if it is right and I'm on the right track.

• John.Heddles
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• ATPL/consulting aero engineer
• Posts: 454

### John.Heddles replied the topic: Landing Distance chart figure 4

Your approach to the problem is fine, but the details require some tweaking.

(a) check 3800 ft - looks a little low to me

(b) check the slope - perhaps you have used 1.0% rather than 1.6% ?

Hence, we really need you to redo the sheet again.

As an aside - the chart has been drawn for gross weight and gross weight approach speed. This technique occasionally was used to save the customer a few dollars in flight test and analysis time. I always detested the short cut as being just a little too rough and ready. On the other hand, if the landing performance for a particular light aircraft was considerably conservative when compared to takeoff distances, one could see some justification.

Usually the short cut lead to the rather strange observation (which generated plenty of pilot queries) of the LDR increasing with reducing weight due to the gross weight approach speed's being too high, leading to an inevitable float penalty.

Evidently, for this particular set of data, the normal distance reduction with reducing weight more or less balanced out the float distance penalty and hence the (not quite correct) note that the distance is independent of the weight.

Engineering specialist in aircraft performance and weight control.