Page 10 - Volume 10 Number 10

PILOT KA SPEAK Breaking Away from
Runway Overruns
The FAA’s New Rules for Runway Condition and Braking Action
by Matthew McDaniel
There is a premise among respectively]. A Mu (or co-efficient thus, issued a holding clearance
professional pilots that some
FAA rules are intentionally vague and often open to interpretation in order to provide operational flexibility (within reason). For years, such has been the case with runway condition assessments and braking action reports. For example, most pilots who have operated under Federal Aviation Regulations (FAR) Part 91K, 135, or 121 have had hard limits for what runway conditions and braking action reports would permit or prohibit a runway’s use. Yet, pilots and controllers alike understand the “game” and what is sometimes necessary to complete the mission, while also remaining firmly within the rules.
Playing the Game
Consider this theoretical situation between a King Air charter operation (Part 135) and Air Traffic Control (ATC). Assume the charter operator’s Operating Specifications (OpSpecs) state that landing is prohibited with braking actions, or Mu-reading equivalents, of less than Fair, with the most recent report being controlling. An airliner is cleared to land on runway 18 and is given the most recent Mu readings for that runway of .30/.30/.30 [touchdown, mid and roll-out zones,
8 • KING AIR MAGAZINE
of friction) measurement of .30 is generally considered to be the bottom of the Fair braking action range, before entering the Fair-to- Poor range of .29 to .26 [see Figure 1]. After landing, the airliner reports braking action as “Poor.” The King Air on approach is told of this latest report. The pilot responds that he cannot land with braking action reported as less than Fair and is,
and told that airport operations will not be taking the next Mu- readings for 40 minutes. Meanwhile, a corporate jet (operating under Part 91), overhears this exchange, completes an approach and landing, subsequently reporting braking action as “Fair” (knowing full well that his report will supersede the previous airliner’s report, thereby allowing the King Air to accept an
Current (New) Braking Action Terminology
Corresponding Runway Condition Code (RwyCC)
Previous Braking Action Terminology
Approximate Corresponding Mu Measurements**
[None, but assumes a Dry condition]
6
[None]
[None]
“Good”
5
“Good”
.40 and above
“Good to Medium”
4
“Good to Fair”
.39 to .36
“Medium”
3
“Fair”
.35 to .30
“Medium to Poor”
2
“Fair to Poor”
.29 to .26
“Poor”
1
“Poor”
.25 to .20***
“Nil”
0
“Poor to Nil”
.20 to .18***
[None]
[None]
“Nil”
.17 or less***
Figure 1: Comparison of New and Previous Braking Action Information*
*The two left columns reflect the new system and terminology, effective Oct. 1, 2016. The two right columns reflect the previous system and terminology, now superseeded, presented strictly for comparative purposes.
** No official correlation between pilot-reported braking action terminlogy and Mu measurements exists under the previous or the new rules and systems, and sources vary slightly on these values. Under the new rules, a RwyCC of 0 is considered “Nil” braking action, rendering that runway closed to all flight operations.
*** Mu readings of less than .25 are considered unreliable and, thus, should be considered to indicate the potential of Nil braking action.
OCTOBER 2016
PAUL BOWEN PHOTOGRAPHY