Use of Weather Information by General 

Aviation Pilots, Part I, Quantitative: 

Reported Use and Value of Providers 

and Products

William R. Knecht

Civil Aerospace Medical Institute

Oklahoma City, OK 73125

March 2008

Final Report

DOT/FAA/AM-08/6

Office of Aerospace Medicine

Washington, DC 20591

OK-08-1997
NOTICE

This document is disseminated under the sponsorship 

of the U.S. Department of Transportation in the interest 

of information exchange. The United States Government 

assumes no liability for the contents thereof.

___________

This publication and all Office of Aerospace Medicine technical reports are 

available in full-text from the Civil Aerospace Medical Institute’s publications 

Web site: 

www.faa.gov/library/reports/medical/oamtechreports/index.cfm


Technical Report Documentation Page 

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. 

DOT/FAA/AM-08/6 

4. Title and Subtitle 5. Report Date 

Use of Weather Information by General Aviation Pilots, Part I, March 2008 

Quantitative: Reported Use and Value of Providers and Products 6. Performing Organization Code 

 

7. Author(s) 8. Performing Organization Report No. 

Knecht WR 

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) 

FAA Civil Aerospace Medical Institute 

P.O. Box 25082 11. Contract or Grant No. 

Oklahoma City, OK 73125 

12. Sponsoring Agency name and Address 13. Type of Report and Period Covered 

Office of Aerospace Medicine 

Federal Aviation Administration 

800 Independence Ave., S.W. 

Washington, DC 20591 14. Sponsoring Agency Code 

15. Supplemental Notes 

Work was accomplished under approved task AM-A-02-HRR-521 

16. Abstract 

Data obtained from 221 general aviation (GA) pilots were examined to determine their usage patterns for 

weather information. Weather products, providers, and en-route information sources were ranked according to 

relative use and rated by perceived information value, frequency of use, and time invested per usage. The 

measures were highly correlated. Conclusion #1: A small fraction of pilots show sparse use patterns and these 

may be at risk for flying with inadequate preparation. Conclusion #2: There seems to be a strong tendency for 

many pilots to prefer relatively simple forms of information (e.g., METARS). This may present a problem, given 

the often-complex nature of weather. 

 

17. Key Words 18. Distribution Statement 

 

 

Weather, General Aviation, Preflight Briefing Document is available to the public through the 

Defense Technical Information Center, Ft. Belvior, VA 

22060; and the National Technical Information 

Service, Springfield, VA 22161 

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price 

Unclassified Unclassified 19 

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized 

iii

ACKNOWLEDGMENTS

The author gratefully acknowledges the efforts of Dennis Beringer and Jerry Ball for data 

collection, of Tom Chidester and Mike Wayda for editing, and of the various site points-of-contact 

who made that data collection possible.

GLOSSARY

ADDS. . . . . . Aviation Digital Data Service

AFSS. . . . . . . Automated Flight Service Station (a.k.a. FSS)

AIRMET. . . . Area Meteorological Forecast

AOPA. . . . . . Aircraft Owners and Pilots Association

ATIS. . . . . . . Automated Terminal Information System

AWOS. . . . . . Automated Weather Observation System

DUATS. . . . . Direct User Access Terminal Service

FAA. . . . . . . . U.S. Federal Aviation Administration

FA. . . . . . . . . Aviation area 18-hour forecast

FD. . . . . . . . . Winds and temperatures aloft

FSS. . . . . . . . Flight Service Station (a.k.a. AFSS)

GA. . . . . . . . . General Aviation

METAR. . . . . Meteorological Aeronautical Report

NEXRAD. . . Next-Generation Radar (Doppler radar)

NOAA. . . . . . National Oceanic and Atmospheric Administration

NWS. . . . . . . National Weather Service

PIREPS. . . . . Pilot Reports

SIGMET. . . . Significant Meteorological Forecast

TAF. . . . . . . . Terminal Aerodrome Forecast

TWC. . . . . . . The Weather Channel

vii

Contents

INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Background and terminology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Purpose of this research. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

METHOD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Design and participants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

RESULTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Weather providers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Weather products. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

En-route sources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Reliability and internal consistency of the data and sample. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Variation in weather information use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

DISCUSSION AND CONCLUSIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Suggestions for further study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

REFERENCES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

APPENDIX A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

APPENDIX B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

Use of Weather Information by General Aviation Pilots, Part I,

 Quantitative: Reported Use and Value of Providers and Products

INTRODUCTION

Background and terminology

The causes of aviation accidents are varied and many. 

Appendix A gives an extensive list (FAA, 2003). However, weather remains a major cause of general aviation 

fatalities. While weather was cited as causal in only 4% 

of general aviation (GA) accidents, it accounted for 12 

to 17% of fatalities, since about 70% of weather-induced 

accidents prove fatal (AOPA, 2005). The linear trend 

lines added to Figure 1 show that the relative involvement 

of weather in GA accidents and fatalities has remained 

relatively stable despite considerable effort spent trying 

to lower it (“fatalities” adj. R2

 = .046, trend line slope = 

-.47, p = .33, NS).

The U.S. Federal Aviation Administration (FAA) has 

a stated current goal of reducing GA fatalities (FAA, 

2006). To this end, weather-related accidents are targeted 

for reduction. But the complexity of weather and the 

corresponding need for pilots to understand the weather 

situation that may impact any given flight requires effective analysis, summarization, and communication of 

weather information. 

Weather information comes mainly in the form of 

products and providers. A wea­ther product is a relatively 

small package of related information constituting a standalone report (e.g., METAR, TAF). Weather providers are 

organizations dedicated to bundling weather products 

into convenient, user-friendly form. The Automated 

Flight Service Station (usually known as the Flight Service 

Station, or FSS) is a good example of a weather provider. 

Providers try to give pilots a strategic sense of the weather 

to complement the tactical sense given by the separate 

weather products themselves. There are many weather 

providers, most of them commercial, for-profit. Highend providers offer features rivaling those available to 

airline dispatchers.

The FAA, the National Oceanic and Atmospheric 

Administration (NOAA), and a number of commercial 

providers make weather information available in formats 

designed to aid pilot decision-making. Yet, in many 

weather-related accidents, investigators found no evidence 

that the pilot sought out or obtained a weather briefing 

(Prinzo, Hendrix, & Hendrix, 2007). This raises a normative question – to what extent do GA pilots actually make 

use of the weather services that are available for them? 

Latorella, Lane, and Garland (2002) conducted a 

national survey, which offers baseline insight into these 

questions. In 1999, they surveyed 97 GA pilots to assess 

their preferences for weather information products and 

providers. At that time, the most “important” (most 

highly rated) individual types of weather information 

were cloud ceilings, convective weather, lightning, icing, 

and visibility. The most important weather products were 

METARs and TAFs. Finally, the most important weather 

providers were the FSSs and DUATS.

Since that time, informational availability and richness 

have both grown, particularly as regards the Internet, so 

the distribution of preferences may have shifted somewhat. 

Also, Latorella et al. focused on perceived information 

availability, usefulness, and importance but did not assess 

the extent of actual usage. Therefore, a follow-on study 

seemed timely.

Purpose of this research

The purpose of this research was to explore how GA 

pilots use available weather information. What information actually is available? What do pilots seem to prefer? 

How much time do they spend in preflight planning for 

a bad-weather flight? Once aloft, what updates do they 

acquire, and how much time do they spend acquiring 

them? 

Total Fatalities Linear trend

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

1998 1999 2000 2001 2002 2003

Year

Percent of accidents ni volv ni g weather

Figure 1. (Lower line) percent of GA accidents 

involving adverse weather. (Upper line) percent 

of total fatalities resulting from those accidents 

(from AOPA’s 2004 Nall Report, derived from 

U.S. NTSB and FAA data). Dashed lines added 

to show linear trend. 
These are relatively straightforward questions. By 

operationalizing them, gathering data, and analyzing the 

result, we can identify salient issues worthy of intervention and/or further study.

To address these questions, we interviewed GA pilots 

concerning their use of weather information products 

and providers. The intent was to establish actual usage 

patterns in the field, in contrast to ideal usage patterns 

as recommended by the FAA. 

METHOD

Design and participants

During July and August 2005, we conducted on-site 

interviews with more than 230 GA pilots at locations across 

5 states (CA, OK, ND, IL, FL). Four of the venues were 

university-based flight schools, the fifth was a helicopter 

training course. Of these 230 interviews, 221 ultimately 

provided usable data (the remainder contained large 

numbers of unanswered questions). Medians were used 

to express averages when means were artificially elevated 

by extreme scores. Median pilot age was 23 years (range 

18-78), median flight experience was 245 hours (range 

15-18,000). Women made up 14% of the sample. All 

were volunteers paid for their services as subject matter 

experts.

Procedure 

Appendix B gives the full, written-interview protocol. 

This interview solicited both quantitative and qualitative 

responses, so both quantitative and qualitative analytical 

techniques were applied to understand weather usage. 

In the qualitative aspect, pilots were asked open-ended 

questions, plus Likert-scale items designed to assess their 

thought processes when making decisions about weather. 

Responses were analyzed according to a coding scheme 

(rubric). These analyses are addressed in a separate paper 

titled “Use of weather information by general aviation 

pilots, Part II, qualitative: Exploring factors involved in 

weather-related decision making.”

The current report focuses on the quantitative aspect. 

Pilots were asked to (a) rate weather products and providers on the basis of how much they typically used them, 

(b) assign each a value based on its information content, 

(c) estimate the percentage of times each was used on a 

“standard flight,” and (d) estimate the number of minutes 

each was used on such a standard flight, when that item 

actually was used. A “standard flight” was defined as a 4-

hour flight through “weather serious enough to challenge 

your skill level and the aircraft’s capabilities.”

RESULTS

Weather providers

Table 1 shows how pilots rated the quality of various 

preflight weather information providers. Pilots supplied 

four ratings, plus one rating arithmetically derived from 

the last two ratings:

Rank reflected the group’s relative rank-ordering of 

how much pilots felt they used any given weather 

provider.

Value was a similar measure, reflecting how valuable 

the group felt that provider’s information was. 

Used on % of Flights referred to the percentage of 

flights on which pilots used each provider (answers 

left blank were coded as 0%). 

Minutes Spent When Used referred to the amount 

of time per flight a given provider was used, if and 

when it was used. 

Average Minutes Spent per flight was the result of 

multiplying Used on % of Flights times Minutes Spent 

When Used. As such, Average Minutes Spent was an 

•

•

•

•

•

Table 1. Normalized ranks, values, frequency of use, and time spent using weather information providers. 

Rank Value 

Provider Format 0-1 0-1 

Used on % 

of flights 

Min spent 

when used 

Ave min 

spent 

FSS (standard briefing) telephone 1.0 1.0 61.5 9.1 5.6

Public NWS or NOAA site Internet 0.7 0.8 49.8 13.9 6.9

DUATS Internet 0.7 0.7 34.0 8.9 3.0

Commercial vendor Internet 0.4 0.5 28.7 5.0 1.4 

The Weather Channel Internet, TV 0.4 0.5 27.9 7.0 2.0 

FSS (outlook) telephone 0.2 0.3 14.4 2.4 0.3 

DUATS at airport 0.1 0.1 11.3 2.1 0.2 

FSS (automated TIBS) telephone 0.1 0.1 8.9 1.5 0.1 

FSS (abbreviated) telephone 0.1 0.2 9.2 1.8 0.2 

Other sources telephone 0.0 0.0 4.3 0.6 0.0 

Total min spent per flight 19.8
estimate of how much time was spent on a given provider on the “average” flight (even though sometimes 

it may have been used and sometimes not). 

Total Minutes Spent Per Flight was simply the column 

sum of Average Minutes Spent Per Flight, totaled across 

all providers (19.8 min in this case).

Note that Rank could be distinct from Value. For instance, we might highly value a Rolls-Royce automobile, 

yet rank it low in terms of use, since we cannot afford to 

actually own one. Similarly, a high-end provider might 

have high value but be cost-prohibitive or require too 

much time investment for a private pilot flying for 

personal reasons.

Ranks and values were equilibrated (normalized) to 

a scale of 0 to 1.0 to allow for easier comparison of the 

data across Rank and Value. Here, “0” represented least 

valuable (or least-used) and “1” represented most valuable (or most-used).

Note that the Flight Service Station standard briefing 

was both ranked and valued highest (1.0) and said to be 

used on the highest percentage of flights (61.5%). This was 

closely followed by the public National Weather Service 

/ National Oceanic and Atmospheric Administration / 

Aviation Digital Data Service (NWS/NOAA/ADDS) 

Web sites, which actually experienced higher minutesspent-when-used and overall average minutes used. 

Internet Direct User Access Terminal (DUATS) also 

•

received high scores across the measures. These findings 

were largely consistent with Latorella et al., although 

Internet use had grown much more prominent.

Commercial vendors received intermediate ranks across 

the board. These were paid services, which probably 

explained their more modest place among this group of 

younger pilots. Certainly, the quality of their information 

was quite high. In fact, much of it came directly from 

NOAA data feeds.

Finally, a surprising number of pilots reported using 

The Weather Channel (TWC), even though it was not an 

FAA-approved source. This was perhaps due to the sheer 

ease of turning on the television and watching. Also, the 

Internet-based TWC had a convenient feature allowing the 

user to type in a zip code and receive easy-to-understand 

forecasts based on current location. TWC seemed to give 

pilots something they wanted—a simple report, local and 

fast. The other sources were far more comprehensive, but 

that breadth came at the expense of extra time and effort 

needed to access and understand them.

Weather products

Table 2 shows how pilots rated the quality of preflight 

weather information products. The format is similar to 

Table 1. These are grouped primarily by Rank and Value, 

and they also show reported use. Again, Rank and Value

were normalized so that direct comparisons could be 

made across those two categories.

Table 2. Normalized ranks, values, frequency of use, and time spent using various weather products. 

Rank Value 

Product Format 0-1 0-1 

Used on % 

of flights 

Min spent 

when used 

Ave 

min

spent 

METAR text 1.0 1.0 77.3 4.5 3.4

TAF text 1.0 1.0 76.5 5.3 4.0

AIRMET / SIGMET text 0.5 0.7 47.6 3.7 1.8

FA (Aviation area 18-h forecast) text 0.5 0.5 36.1 3.2 1.2

Charts, Radar (NEXRAD) graphic 0.5 0.6 44.2 3.6 1.6

ATIS (Automated Terminal Information System) radio 0.4 0.5 41.4 2.0 0.8

AWOS (Automated Weather Observing System) radio 0.3 0.4 25.0 1.8 0.5

Charts, Radar summary graphic 0.3 0.4 23.7 1.7 0.4

FD (Winds and temps aloft) text 0.3 0.4 30.0 2.2 0.7

PIREP text 0.3 0.6 36.4 2.2 0.8

ASOS (Automated Surface Observing System) radio 0.2 0.2 13.0 0.8 0.1 

Charts, Prognostication graphic 0.2 0.3 17.8 1.7 0.3 

Charts, Weather depiction graphic 0.2 0.3 15.1 1.8 0.3 

Satellite (images of cloud cover) graphic 0.2 0.3 20.9 1.8 0.4 

Charts, Air- or Surface-analysis graphic 0.1 0.2 12.8 1.0 0.1 

Charts, Convective outlook graphic 0.1 0.1 10.1 1.1 0.1 

GPS (Global Positioning Satellite) T or G 0.1 0.1 5.1 0.5 0.0 

TWEB (Transcribed Weather Broadcast) radio 0.1 0.1 9.0 0.9 0.1 

AC (Severe Wx Outlook Narrative) text 0.1 0.1 4.7 0.4 0.0 

FD graphic 0.0 0.1 5.3 0.4 0.0 

LLWAS (Low Level Wind shear Alerting System) radio 0.0 0.0 0.9 0.1 0.0 

SD (hourly weather reports) text 0.0 0.0 3.9 0.4 0.0 

WW, AWW (weather watch bulletins) text 0.0 0.0 0.1 0.1 0.0 

Other sources 0.0 0.0 0.1 0.0 0.0 

Total min spent per flight 16.6
The most highly ranked, valued, and used weather 

products for this group were METAR and TAF. This 

was followed, rather distantly, by AIRMET/SIGMET, 

FAs, and radar charts. Finally, ATIS, AWOS, radar summary charts, FD, and PIREPs showed ratings clustered 

roughly in third place. 

The total estimated average number of minutes per 

flight spent reviewing weather products was 16.6. This 

was reasonably consistent with the 19.8 min estimated 

for providers (the importance of this will be discussed 

in greater detail later).

En-route sources

Similarly to the previous two tables, Table 3 shows 

pilot ratings for the quality of en-route information 

sources, again sorted by Rank. Two relatively simple 

sources—ATIS, and AWOS were most highly ranked., 

Flight Watch, and ASOS were moderately ranked. 

Reliability and internal consistency of the data and 

sample

Reliability is the sine qua non of measurement. It 

means that, if we did the same study again with the same 

pilots, we should see results highly similar to the original 

measurement. The standard way of assessing reliability is 

by test-retest. However, privacy concerns precluded that 

approach here. So, a number of alternate means were 

used to assess reliability. 

First, we compared the overall time pilots said they 

spent on weather products (16.6 min) versus on providers (19.8 min). These two numbers should have been 

similar, and they were. Next, since “providers” consisted 

of “products plus other services,” the time spent on 

providers should have been slightly greater than that for 

products, and it was.

Intercategory correlations are a second way of assess-

ing reliability. Where multiple questions are asked about 

similar things, and respondents give logically consistent 

answers across categories, it can be assumed that most 

respondents are answering items thoughtfully rather than 

randomly. Rank, Value, Percent Use, and Minutes Used all 

measured logically related aspects of value to pilots here. 

Therefore, they should be strongly intercorrelated as long 

as participants did not answer randomly. 

This was reflected in the results. Table 4 shows the 

high groupwise category intercorrelations, ranging from 

.89-.99. All Pearson rs were significant at p < .01. This 

implied that the four measures were logically related. 

In other words, pilots tended to use information and 

information sources that they value highly (or vice 

versa—correlation does not specify exactly what causes 

what). It also implied that in future studies it is probably unnecessary to use all four measures. Percent Use

and Minutes Used are probably sufficient; both to check 

reliability and to estimate the total minutes each pilot 

spends on weather briefings. 

Table 3. Normalized ranks, values, frequency of use, and time spent using various enroute weather sources. 

Rank Value 

Enroute source 0-1 0-1 

Used on % 

of flights 

Min spent 

when used 

Ave min 

spent

ATIS 1.0 1.0 75.6 4.6 3.5

AWOS 0.6 0.7 48.7 4.1 2.0 

EFAS (FSS Flight Watch) 0.4 0.6 29.1 4.1 1.2 

ASOS 0.3 0.4 23.6 1.6 0.4 

HIWAS (Hazardous Inflight Weather Advisory System) 0.2 0.3 14.0 1.4 0.2 

Avionics 0.1 0.0 8.3 1.2 0.1 

TWEB 0.0 0.0 2.6 0.4 0.0 

Other sources 0.0 0.0 4.0 0.3 0.0 

Total min spent per flight 7.3

Table 4. Provider, product, and enroute source intercorrelations. 

Provider intercorrelations Product intercorrrelations Enroute source intercorrelations

 Rank Value % Min Rank Value % Min Rank Value % Min 

Rank 1 1 1 

Value 0.993 1 0.975 1 0.979 1 

% 0.988 0.987 1 0.987 0.993 1 0.994 0.961 1 

Min 0.896 0.910 0.902 1 0.954 0.972 0.966 1 0.927 0.960 0.898 1 

Table 5. Split-sample within-item correlations. 

Rank Value % Min 

0.989 0.984 0.984 0.967 
A third way to estimate reliability is to randomly split 

the sample in half to see if each half shows similar scores on 

the various items. Table 5 shows the Pearson rs generated 

by this process. All correlations were significant at p < .001. 

This implied that, not only was our sample statistically 

stable, but also that in the future a sample half as large 

would probably be sufficient, if carefully chosen.

The one thing these reliability estimates did not address was the underlying representativeness of the sample 

itself. The questions appeared internally consistent and 

stable, as did the sample itself. But was the actual sample 

truly representative of all pilots nationwide? That was 

an important question. Unfortunately, truly random 

sampling methods were not available for this study due 

to time, financial, and privacy constraints. These were 

predominantly student pilots, and we must keep this fact 

in mind if we wish to generalize these results to pilots at 

large. On the positive side, these individuals were predominantly (a) far from new to flying and (b) certainly 

quite representative of the next generation of pilots, which 

is extremely useful for strategic planning purposes.

Variation in weather information use

Table 6 summarizes the estimated average number of 

minutes these pilots reported spending on bad-weather 

briefing, using preflight providers, products, and en-route 

sources. Minimums, maximums, ranges, and bottom 5th 

and 10th percentiles are shown.

The group means looked acceptable (19.8 min use of 

preflight providers and 16.6 min for products, plus 7.3 min 

use of en-route sources). However, the data did point to a 

small percentage of pilots who focused too little on prepar-

ing for, and monitoring, potentially challenging weather. 

The minimums suggested that a few pilots did very little 

preflight preparation and nearly no weather monitoring 

once aloft. Ten percent of pilots reported spending less 

than 9 min on providers, less than 8.8 min on products, 

and less than 2.5 min on en-route updates. Five percent 

reported spending less than 7.1 min on providers, 5.1 

on products, and 1.8 on en-route updates.

DISCUSSION AND CONCLUSIONS

The purpose of this research was to try to understand 

how GA pilots use the weather information available to 

them. This included documenting what weather sources 

were currently available, measuring pilot preferences for 

different providers and products, and assessing what 

preflight and en-route sources they reported using. Recall 

that a wea­ther product (Table 1) is a small package of related 

information constituting a stand-alone report. Weather 

providers (Table 2) are organizations dedicated to bundling 

weather products into user-friendly formats. 

For this study, 221 licensed GA pilots were sampled 

from 5 different instructional venues across the U.S. 

When asked how they typically prepared for a standard 

4-h flight into weather bad enough to challenge their 

skills and the aircraft’s capabilities, these pilots indicated 

a strong group preference for FSS standard briefings, 

NOAA/NWS Internet providers and, surprisingly, the 

Weather Channel.

An important finding here was that many pilots reported 

preferring relatively simple preflight weather products 

(METAR, TAF, AIRMET/SIGMET, FA) over more complex, yet informationally richer materials available (e.g., 

NEXRAD radar images). This has deep implications for 

the design of future weather products, particularly those 

on the Internet. Weather is complex by its very nature, 

and the challenge is to express that complexity in ways 

simple enough to be useful to the flying public.

These data gave a sense of how the latest generation of 

pilots appeared to use weather information. On average, 

these pilots estimated spending 19.8 min with preflight 

weather providers, 16.6 min with preflight weather products, and 7.3 min with en-route sources. Those averages, 

alone, might be considered adequate. However, there 

was considerable variability in the estimates, indicating 

that inadequate preparation might be anticipated by 

roughly 10% of pilots. Naturally, “time spent using” 

was not a perfect proxy for “amount learned,” so we 

must not jump to the hasty conclusion that quantity of 

use equals quality of use. Nonetheless, even with that 

caveat, these data probably point to an identifiable group 

in need of attention.

Table 6. Estimated average min spent on weather briefings 

by providers, products, and enroute sources. 

Providers Products En-route 

Average time spent 19.8 16.6 7.3

Minimum 3.10 3.97 0.99 

Maximum 138.5 154.6 92.0 

Range 135.4 150.6 91.0 

Bottom 10th percentile 9.0 8.8 2.5 

Bottom 5th percentile 7.1 5.1 1.8 
To summarize, Conclusion #1 is that, despite the acceptable group averages on preflight and in-flight attention to weather, there seemed to be individuals spending as 

little as 3-4 min on preflight weather briefing and less than 

one minute on updates, once airborne. The lowest 10% 

of pilots reported spending less than 9 min on preflight 

adverse-weather briefing and less than 2.5 min on enroute updates.

Conclusion #2 is that, while many pilots seem to value 

and use modern, sophisticated weather information providers, there seems to be a strong, counter-tendency to value 

and use that which is simplest, even if simplicity comes at the 

cost of greater risk. The most popular weather information 

products and en-route sources sampled here seemed to be 

among the simplest (e.g., METARs and TAFs). This has 

serious implications for user interface design, certification, and training. 

It also may reflect a problem for some pilots, given the 

inherently complex nature of weather. While complex 

weather information may be available, it is not always 

what is sought out or understood. From a human factors 

perspective, there is a lesson for information system design 

in this: Weather information needs to be

convenient

comprehensive, and

simple to understand,

or there will be some pilots who either fail to acquire 

it or fail to understand it. 

Unfortunately, these 3 points are in competition. That 

which is convenient tends not to be comprehensive. That 

which is comprehensive can be difficult to understand. 

Therein lies a major challenge for the future.

A second challenge lies in the complexity of the way 

weather factors interact with each other and the flight 

situation. Knecht, Shappell, and Harris (2005) demonstrated significant visibility x cloud ceiling interaction 

in GA pilots’ decisions whether or not to take off into 

marginal VFR weather. Driskill, Weissmuller, Quebe, 

Hand, and Hunter (1997) also noted interactions 

between visibility, ceiling, precipitation, and terrain. 

In other words, the challenge is not merely to identify 

a static set of “most significant weather factors.” The 

problem is more complex than that. Specific circumstances matter (including factors like terrain, aircraft 

type, time of day, and so forth). Weather provokes 

both “go/no-go” decisions and “continue/hold/divert” 

decisions, and the values of specific factors interact in 

determining the most appropriate decision. So a list of 

“most-important weather factors” undoubtedly shifts, 

given the unique circumstances of each flight. In the 

present study, our results apply to a “typical” 4-hour 

•

•

•

flight into anticipated-but-unspecified bad weather. 

Had we set up a different scenario, we might assume 

the dynamics of decision-making would shift somewhat 

with the specified circumstances.

These findings are directly comparable to, and extend, Latorella et al.’s survey of GA pilot weather use in 

1999. Both that study and the present research indicate 

that ceilings, convective weather, lightning, icing, and 

visibility remain prominent as primary information of 

concern to airmen. FSS also remains a versatile, popular 

weather information provider. DUATS is still highly 

valued and used, though it may have lost ground to 

NOAA/NWS Internet services. Finally, METARs and 

TAFs were popular weather products then, and are still 

at the top of the list now. 

The Internet is clearly gaining ground. While Internet 

weather information has become more available, sophisticated, and used in the 6 years between these samples, the 

raw information most GA pilots want to know appears to 

have largely stayed the same. Given recent investments in 

improving weather information quality and availability, it 

is surprising that longstanding sources such as METAR 

and TAF were rated so highly by users. This may parallel 

The Weather Channel’s popularity in a tendency for users 

to want brevity and simplicity in summaries of weather 

information. This preference for simple weather products 

may belie the apparent “techno-savvy” of the next generation of pilots. In actuality, there may still be a relative 

lack of sophistication regarding the particular information 

they are retrieving, understanding, and using. Weather is 

complex, and all presentations of it are simplifications in 

some fashion. So how do we present the essentials without 

overwhelming the user? This is a major challenge for all 

of us concerned with keeping the blue side up.

Suggestions for further study

In future studies, it is recommended that fewer polling 

variables are needed (specifically, Frequency of Use and 

Average Minutes Spent Using are probably sufficient). 

Future sample sizes probably do not need to exceed 100 

pilots, provided that care is given to sampling both diverse 

geographic areas and pilot occupations. New studies 

should also consider validating survey instruments with 

standard test-retest reliability methods. Flight duration 

could be explored as an independent variable. Certainly, 

the sub-group of “low-use” and “simple-information-use” 

pilots described here may constitute an at-risk group 

worth investigating. Finally, the possible utility of lowcost, PC-based weather training comes to mind, as well 

as the similar utility of low-cost, hand-held weather 

information devices.
REFERENCES

AOPA Air Safety Foundation. (2005). Nall Report--

Accident trends and factors for 2003. Frederick, 

MD: Airline Owners and Pilots Association. 

Downloaded Dec. 22, 2005 from www.aopa.

org/asf/publications/ 04nall.pdf.

Driskill, W.E., Weissmuller, J.J., Quebe, J.C., Hand, 

D.K., & Hunter, D.R. (1997). The use of weather 

information in aeronautical decision-making: II. 

(Technical Report DOT/FAA/AM-97/23). Wash-

ington, DC: Federal Aviation Administration, 

Office of Aviation Medicine.

Federal Aviation Administration. (2003). FAA/industry 

training standards personal and weather risk assessment 

guide. Downloaded Dec., 23, 2005 from www.faa.

gov/education_research/ training/fits/guidance/

media/Pers%20Wx %20Risk%20Assessment% 

20Guide-V1.0.pdf.

Federal Aviation Administration. (2006). Flight Plan 

2006-2010. Washington, DC: Federal Aviation 

Administration. Downloaded Feb. 24, 2005 from 

www.faa.gov/about/plans_reports/media/flight_

plan_ 2006.pdf.

Knecht, W., Harris, H., & Shappell, S. (2005). The 

influence of visibility, cloud ceiling, financial incentive, and personality factors on general aviation pilots’ 

willingness to take off into marginal weather, Part I: 

The data and preliminary conclusions. (Technical 

Report DOT/FAA/AM-05/7). Washington, DC: 

Federal Aviation Administration, Office of Aerospace Medicine.

Latorella, K., Lane, S., & Garland, D. (2002). General 

aviation pilots’ perceived usage and valuation of aviation weather information sources. (Technical Report 

NASA/TM-2002-211443). Springfield, VA: National Technical Information Service.

Prinzo, O.V., Hendrix, A.M. & Hendrix, R. An analysis of 

preflight weather briefings. (Technical Report DOT/

FAA/AM-07/4). Washington, DC: Federal Aviation 

Administration, Office of Aerospace Medicine.

A-1

APPENDIX A

List of proposed causal factors for weather-related GA accidents

Table 7. Known weather risk factors.

ENVIRONMENT FACTORS 

PERSONAL FACTORS Visibility marginal (< 5 miles) 

< 100 h in type Destination visibility < 1 mile 

Unfamiliar destination Ceilings < 3,000’ AGL 

Fatigue (less than normal sleep prior night) Destination ceilings < 1,000' AGL 

Flight after end of work day Convective activity within 20 NM of flight 

Scheduled commitment after flight

Recent death of close family member 

No de-icing equipment surface temperatures < 40°F and clouds or 

precipitation

Major domestic problems

Illness in family 

Icing forecast (AIRMET more than light) at altitude required to fly with 

de-icing equipment 

No second pilot who is rated and current Convective activity w no storm scope or other detection capability 

Alcohol within the last 24 hours Destination dew point spread < 3° 

Taking over-the-counter medication No operational control tower at destination 

Inadequate food prior to flight No VASI/PAPI at destination 

Inadequate water prior to flight/ no water on board No radar environment at destination 

Day > 10,000’ with no supplemental oxygen Mountainous terrain 

Night > 5,000’ with no supplemental oxygen Approach/departure over water 

Flight duration more than 3 hours High bird hazard 

Unpaved runway 

OPERATIONAL FACTORS IFR and only approach is non-precision 

Fuel calculation and reserves incomplete for day/night 

conditions

Crosswind in excess of 90% demonstrated maximum crosswind in 

Pilot Operating Handbook 

Weight & balance calculation not made No weather reporting at airport 

Weight within 10% max. gross Precipitation causing obstruction to visibility 

Takeoff or landing distance more than 50% of intended 

runways to be used 

No use of flight following or radar advisories in high density traffic 

areas

Wet runway 

Ice on runway 

Source: Adapted from Federal Aviation Administration. (2003). FAA/Industry Training Standards personal and weather risk assessment guide. No IFR Flight plan in VFR conditions 

B-1

APPENDIX B 

Interview instrument used in this study 

1. Age____ 

2. Gender (male __, female __) 

3. Primary occupation ______________________________________________________________ 

4. Other current occupation(s)____________________ 

5. Past occupations(s) related to aviation________________________________________________ 

6. Certificates and ratings (check each that applies) 

Sport Airplane Single-Engine 

Recreational Airplane Multiengine 

Private Rotorcraft 

Commercial Balloon 

ATP Airship 

Instrument Glider 

Flight Instructor Powered-Lift 

7. Type of flying you do (to the nearest 10 percent, for example, recreational 20%)

 recreational____ business____ corporate____ commercial____(these should add to 100%) 

For questions below, “general aviation” (GA) means “any small aircraft not flying for hire.” 

8. Your total GA flight hours (best guess) ___________ Total hours in last 90 days___________ 

9. Do you own your own GA aircraft, either by yourself or as a member of a partnership? (Y / N) 

10. Type(s) of GA aircraft usually flown:________________________________________________ 

11. Your normal personal minimum for GA VFR visibility ________ statute miles 

12. Your normal personal minimum for GA VFR cloud ceiling ________ feet AGL 

For questions below, if you’re not a U.S. citizen, use “country” instead of “state” 

13. Current home state (legal residence) _______________________ 

14. Approximate percentage of time you’ve flown GA in your home state _____% versus outside your home 

state _____% (estimate—should add up to 100%) 

15. State(s) where you received GA pilot training____________________________

16. States where you’ve flown GA (put a check mark D in each state name below)

If your flying has been largely 

outside of the USA, please list 

below the countries in which you 

regularly fly and the percentages 

of time spent in each (estimates) 

Country % time 

SME#
B-2

This is a study about how GA pilots use weather information. Please bear in mind these things: 

A. We already know the “textbook answers” for how pilots are supposed to use weather information. What we 

need to know is how real pilots are using real weather information in the real world. 

B. Your responses are strictly anonymous and confidential. 

C. In the next section we’ll refer to “cross-country flights.” That may mean different things to different people. So define “cross-country” as: 1) Non-local airport, far enough away that the weather could surprise 

you.

D. “Bad” weather can also mean different things. So define it as: Weather serious enough to challenge your 

skill level and the aircraft’s capabilities.

SECTION TWO: CROSS-COUNTRY, BAD WEATHER GA FLIGHT 

17. This question will ask details about how you get a PREFLIGHT weather briefing for CROSS-COUNTRY, 

GA FLIGHT when you ANTICIPATE BAD WEATHER. Use the definitions of “cross country” and “bad 

weather” from above in forming your responses. 

a. When do you start planning such a flight? (for example, the day before, the morning of, etc.) 

b. Where do you start researching the weather? (e.g., at home? At the airfield?) 

(Below, a weather “product” is a single report like a METAR, TAF, ASOS, or AWOS. A 

“provider” is an organization like the FSS that bundles individual products together to 

give a comprehensive wx outlook) 

c. List the main weather information provider(s) you consult. List the main products you use from 

each provider. What relative importance do you give to these products? (write “1” by the most important product, “2” by the second-most important product, etc. 

d. About how many minutes does usually it take to finalize your bad-weather GA plan?______ 

e. List the major weather factors that would immediately trigger a no-go decision before takeoff. 

f. What weather factors would lead you to divert a flight in progress? 
B-3

g. Is there any time you anticipated bad weather but took off without planning for it? If so, describe it 

briefly. Remember—this is 100% anonymous, so do NOT name names of individuals involved. 

h. Have social or business pressures ever influenced your GA go/no-go weather decision? (For example, have you ever made a risky flight on a dare, or has a boss ever pressured you into flying 

against your better judgment?). If so, describe it, taking care not to name names. 

i. In plain words, describe what goes through your mind in planning for bad-weather, cross-country 

GA flight. 

j. Briefly, how does your good-weather planning differ from your bad-weather planning? 

k. If there were one thing you’d like to see improved about weather information, what would it be? 
B-4

SECTION 3: CROSS-COUNTRY, BAD-WEATHER INFO. SOURCES (IN-DEPTH REPORT)

(As before, a “product” is a single report. A “provider” combines products to give a big picture) 

18. Evaluate the top 5 preflight weather providers you use most to plan a cross-country, bad-weather flight. 

a. Rank: Using the 1-to-5 scale below, rank ONLY your 5 most-used providers (leave others 

blank).

1 2 3 4 5 

 most-used above average average below average least-used 

b. Value: Using the 1-to-5 scale below, rate the information value of each of those top 5 choices. 

1 2 3 4 5 

 excellent above average average below average poor 

c. %: Estimate the percentage of cross-country, bad-wx flights you use each of these top 5 providers 

on. (NOTE: In 18c, 19c, and 20c, the percentages do NOT have to add up to 100%) 

d. Minutes: Estimate the average number of minutes spent on each of the 5 during bad-wx preflight. 

Rank Value Provider Format Details % of flights Minutes

1-5 1-5 used on spent

Commercial vendor Internet Wx via internet, paid (Which site?__________________)

Public NWS or NOAA site Internet Wx via internet, free (Site(s)? _____________________)

DUATS Internet FAA Direct User Access Terminal

DUATS at airport

FSS telephone Flight Service Station, automated briefing (TIBS)

FSS telephone FSS standard briefing

FSS telephone FSS, abbreviated briefing

FSS telephone FSS, outlook briefing

The Weather Channel Internet,TV Cable TV weather

Other sources List_________________________________________
B-5

19. The same way you did in Q18, evaluate the top 8 preflight weather products you use most in planning a 

cross-country, bad-wx flight. “Text” format means sources you read yourself or that are read to you. 

a. Rank ONLY your 8 most-used products. Write “1” next to the source you use most, etc. 

b. Rate the value each of these 8 using the 1-5 scale of Q18b, for its information value.

c. Estimate the percentage of cross-country, bad-wx flights during which you used each of the 8. 

d. Estimate the average number of minutes spent on each of the 8 during bad-wx preflight. 

Rank Value Product Format Details % of flights Minutes

1-8 1-5 used on spent

AC text Severe Wx Outlook Narrative (2-day convective outlook)

AIRMET / SIGMET text Icing, turbulence, IFR, convective advisories, watches

ASOS radio Automated Surface Observing System

ATIS radio Automated Terminal Information Service

AWOS radio Automated Weather Observing System

charts, Air- or Surface-analysis graphic Constant-pressure (isobar) charts

charts, Convective outlook graphic 48-hr forecast charts for T-storm activity

charts, Prog. graphic 12, 24-hr prognostication charts w. isobars, wx symbols

charts, Radar (NEXRAD) graphic Doppler radar maps

charts, Radar summary graphic Maps of precipitation regions

charts, Weather depiction graphic Maps with isobars, precip, IFR regions, ceilings

FA text Aviation area 18-hr forecast

FD text Winds and temps. aloft 12-hr forecast charts

FD graphic Winds and temps. aloft 12-hr forecast charts

GPS T or G Global positioning satellite

LLWAS radio Low-Level Wind Shear Alert System (at airports)

METAR text Meteorological Aviation Routine

PIREP text Pilot reports

Satellite graphic Satellite photos of cloud cover

SD text Radar weather reports (hourly)

TAF text Terminal Aerodrome Forecast

TWEB text Transcribed Weather Broadcast (over telephone)

WW, AWW text Weather Watch bulletins, severe

Other sources List_________________________________________

20. The same way you did in Q18, evaluate the top 3 en route weather sources you use most during a crosscountry, bad-weather flight (here, a “source” can either be a product or a provider). 

a. Rank: Rank ONLY your 3 most-used sources. Write “1” next to the source you use most, etc. 

b. Value: Using the 1-5 scale of Q18b, how do you rate each of these 3 source’s information value? 

c. %: Estimate the percentage of cross-country, bad-weather flights you use these 3 sources on. 

d. Minutes: Estimate the average number of minutes you spend on each during bad-wx flight. 

Rank Value Source Details % of flights Minutes

1-3 1-5 used on spent

avionics (e.g. on-board radar, Stormscope, etc) List_______________________

ASOS Automated Surface Observing System

ATIS Automated Terminal Information Service

AWOS Automated Weather Observing System

EFAS Enroute Flight Advisory System (Flight Watch through FSS)

HIWAS Hazardous Inflight Weather Advisory System (selected VORs)

TWEB Transcribed Weather Broadcast (over VOR, NDB)

Other sources List_________________________________________

21. Are there reasons why the preflight and enroute sources you USE most aren’t the ones you VALUE most? 

If so, why? (For example, some of the graphic Internet products download slowly on a modem. Or some 

products may be unavailable. Or you might consider some too incomplete or unreliable). 

22. What percentage of FSS briefers do you think are National Weather Service-certified? (best guess) _____ 

23. What percentage do you think are pilots? _____ 
B-6

24. Would it matter to you if your briefer were not a pilot, as long as he/she were NWS-certified? (circle answer)

 1 2 3 4 5 

 not at all a little bit somewhat quite a bit an extreme amount 

25. If you use FSS weather briefings, how satisfied are you with them? (leave blank if you don’t use FSS) 

 1 2 3 4 5 

 not at all a little bit somewhat quite satisfied extremely satisfied

26. What is the typical number of weather reporting stations (e.g. KOKC, KDWF) you check before an average 

4-hour, bad-weather GA flight?____ The smallest number?_____ The largest number?_____ 

Regarding VFR LOCAL FLIGHT, what percentage of the time do you do the following (0-100%)? 

27. I get a briefing on the weather before I take off ____ 

28. I request weather updates during flight ____ 

Regarding VFR CROSS-COUNTRY FLIGHT, what percentage of the time do you do the following? 

29. I get a briefing on the weather before I take off ____ 

30. I request weather updates for route & destination during flight ____ 

Answer questions 31 through 34 using a scale of “0” through “6 or more”: How many times have you ... 

31. become so disoriented that you had to land or call ATC for assistance in determining your location? ____ 

32. flown into areas of IMC without an instrument rating or an instrument-qualified aircraft? .......... ____ 

33. become so disoriented after entering IMC that you had difficulty in maintaining aircraft control? ____ 

34. turned back or diverted to another airport because of bad weather while on a VFR flight? ........... ____ 

Use the scale below to answer Qs 35-38 

 1 2 3 4 5 

 not at all a little bit somewhat quite a bit an extreme amount 

35. How much does the distance you have to fly through bad weather affect your willingness to fly? ____ 

36. Does having non-family passengers affect your willingness to fly in bad weather?.................... ____ 

37. Does having family passengers affect your willingness to fly in bad weather? ........................ ____ 

38. Has social or corporate pressure ever affected your willingness to fly in bad weather? ............... ____ 

39. Have you ever had a life-threatening flight experience related to weather? (Y / N) ................... ____ 

 (On Q 39, if answer is 3, 4, or 5, please briefly describe your experiences). 

THIS CONCLUDES THE SUBJECT MATTER EXPERT INTERVIEW. THANKS AGAIN.