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Table 11. Estimate of potential savings from a 10-min improvement
in lightning delays during the 7 a.m. to 8 p.m. core period at MCO.
Total Annual
Number of Total Annual Potential Annual Per Minute Potential
Type of Event Events Minutes Delay Minutes Saved Cost ($) Savings ($)
Short 40 1,385 400 2,383 953,200
Medium 15 1,674 150 11,099 1,664,850
Long 1 184 10 18,332 183,322
All 56 3,243 560 5,002* 2,801,372
*Weighted average, calculated with Total Annual Potential Savings divided by Potential Annual Minutes Saved.
30/15 Analysis When events overlapped peak hours and nonpeak hours, the
duration of the event was only taken as the duration that
To evaluate the sensitivity of the predicted economic im- occurred during the peak hours. Note that in the ORD analy-
pact on the interval between the last lightning strike and a sis, the single long duration event ended after the peak-hour
return to normal operations, we conducted an additional period, resulting in no delay savings for that event.
set of analyses reducing the all-clear time from 30 min to The results for ORD, shown in Table 13, indicate a potential
15 min after the last reported lightning strike within 6 mi savings of approximately $3.4 million for the summer, based
of the airport. Based on the surveys reported in Chapter 2, on hypothetical implementation of the 30/15 rule. The results
this time interval may be more common than the "stan- for MCO are perhaps more intriguing. In this case, the change
dard" 30 min used for general outdoor activities. This would hypothetically have increased the number of short-term
"30/15" analysis was conducted for the summer months events from 24 to 36, while reducing the number of medium-
(JuneAugust) when lightning activity is most frequent. term events from 12 to 8. The shorter "all-clear" time provides
The 30/15 summer 2006 delay data for ORD and MCO are limited openings in the ramp closures and reduces the number
included in Appendix A. A summary of these analyses are of longer and more costly delays. In our hypothetical analysis,
presented in Table 12. this results in a potential savings of $6.3 million at MCO for the
The rule change from 30/30 to 30/15 results in a slight in- summer of 2006, as shown in Table 14.
crease in the number of events because of a few cases where
the airport would be opened and then quickly closed again
under the 30/15 rule (causing two events instead of one to be
Findings
recorded), while the airport would stay have stayed closed This cost analysis indicates that delay cost impacts are com-
under the 30/30 rule. While this could represent an increased plex. They are a function of several factors, including the activity
hazard for ramp personnel, it results in a significant reduc- levels and mix of aircraft operating at an airport, the number of
tion in delay time, totaling 354 min at ORD and 1,568 min lightning events, the timing of the lightning event, the type
at MCO. of lightning event (local convective or associated with broad-
The corresponding cost impact of the 30/15 summer scale flow), the duration of the lightning event, and the rules the
(JuneAugust) improvement for both ORD and MCO air- airline/airport operators use in issuing the "all clear" signal to
ports was calculated by analyzing the improvement in total resume ramp activity. The analysis also indicates that the annual
delay time for each duration event during peak operating value of new technologies or new procedures that could reduce
hours only and then multiplying the duration delay savings in ramp lightning delays, although varying by airport, could be
minutes by the previously calculated per-minute delay costs. substantial. The potential savings produced by a reduction of
Table 12. Impact of replacing the 30/30 rule with a 30/15 rule.
Number of Events By Rule Minutes of Total Delay By Rule
Airport 30/30 30/15 Change 30/30 30/15 Change
Chicago (ORD) 26 28 2 1,922 1,568 -354
Orlando (MCO) 78 87 9 5,544 3,976 -1,568
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Table 13. Potential savings with 30/15 rule, ORD
JuneAugust 2006.
Delay By Rule Savings With 30/15 Rule
Delay Duration 30/30 30/15 Change Per Minute ($) Total ($)
< 60 min 421 284 137 5,362 734,594
60-180 min 514 408 106 25,032 2,653,392
> 180 min 184 184 0 33,845 0
Total 1,120 876 243 13,942* 3,387,986
*Weighted average, calculated with Total Savings divided by Total Change.
Table 14. Potential savings with 30/15 rule, MCO
JuneAugust 2006.
Delay By Rule Savings With 30/15 Rule
Delay Duration 30/30 30/15 Change Per Minute ($) Total ($)
< 60 min 819 810 9 2,383 21,477
60-180 min 1,415 847 568 11,099 6,304,322
> 180 min 0 0 0 18,332 0
Total 2,234 1,657 577 10,963* 6,325,799
*Weighted average, calculated with Total Savings divided by Total Change.
even a few minutes would likely be sufficient to more than cover VPT = value of passenger time, and
the cost of introducing improved technology or practices. NOPID = number of passengers per plane incurring delay.
As a general guideline, the costs of direct lightning dura-
tion delays at any given airport may be approximated by the When compared against the potential cost of implement-
following equation: ing improved lightning monitoring and forecasting systems,
the analysis indicates that the annual value of new tech-
TALAC = NPAD NRPP ORRW TAD + VPT nologies or procedures for reducing ramp lightning delays,
NOPID TAD although varying by airport, could be substantial. The po-
tential savings produced by a reduction of even a few minutes
where would likely be sufficient to more than cover the cost of
introducing the improved technology or procedures.
TALAC = total annual local airport cost, Because safety of the ramp workers is the paramount con-
NPAD = number of planes affected during a delay, cern, it appears the airlines will likely err on the side of cau-
NRPP = number of ramp workers per plane, tion in closing ramp operations. This suggests that the most
ORRW = overtime rate of ramp work, likely path to improved operational efficiency is in being able
TAD = total annual delay minutes for delays over 60 min to sound an "all clear" as quickly as possible after the initial
(medium- and long-term delays), event, so long as it can be done without compromising safety.
