Part 1: Chapter 5 —… | FAA Weight-Shift…

Introduction

Preﬂ ight preparations should include the overall evaluation

of the:

• Pilot: experience, sleep, food and water, drugs or

medications, stress, illness

• Aircraft: certiﬁ cates/documents, airworthiness, fuel,

weight (does not exceed maximum), performance

requirements, equipment

• En Vironment: weather conditions, density altitude,

forecast for departure and destination airﬁ elds, route

of ﬂ ight, runway lengths

• External pressures: schedules, available alternatives,

purpose of ﬂ ight

Often remembered as PAVE, it is important to consider each

of these factors and establish personal minimums for ﬂ ying.

Preﬂ ight and

Ground Operations

Chapter 5

Figure 5-1. Contact the local airport management to find an acceptable location to stay at the airport.

Figure 5-2. Contact local airport management to determine best operation for the aircraft and its type of operation.

Normal Airplane Traffic Pattern

Normal WSC/Slow Aircraft Traffic Pattern

Alternate WSC/Slow Aircraft Traffic Pattern

Airport Runway

Where To Fly

The weight-shift control (WSC) aircraft can be transported by

trailer from one ﬂ ying ﬁ eld to the next. For as many beneﬁ ts

as this provides, transporting the aircraft into unfamiliar

territory also includes some safety and operational issues.

Contact airport management to inquire about any special

arrangements to be made prior to arriving by trailer

[Figure 5-1] and there may be special considerations for

ﬂ ying WSC aircraft with other aircraft. With smaller patterns

typically used by WSC aircraft, as covered in Chapter 10,

Airport Trafﬁ c Patterns, airport management may want a

pilot to operate over sparsely populated areas rather than

the normal airplane patterns over congested areas because

of the unique noise of the WSC aircraft. [Figure 5-2] Check

the Airport/Facility Directory (A/FD) all required airport

information per Title 14 of the Code of federal Regulations

(14 CFR) part 91 section 103, Preﬂ ight information. Some

operation examples are trafﬁ c pattern information, noise

abatement procedures , no ﬂ y zones surrounding the airport,

and special accommodations that may need to be arranged

for WSC aircraft..

Because of the wide range of flying characteristics of

the WSC aircraft, inform local pilots about some of the

incidentals of the speciﬁ c WSC aircraft (e.g., ﬂ ying low and

slow for certain conﬁ gurations). The more non-WSC aircraft

pilots know about WSC ﬂ ight characteristics and intentions,

the better they understand how to cooperate in ﬂ ight. Sharing

the same airspace with various aircraft categories requires

pilots to know and understand the rules and understand the

ﬂ ight characteristics and performance limitations of the

different aircraft.

Figure 5-3. Fields that look like good landing areas from the air

may actually be hazardous.

Figure 5-4. Standard surface analysis showing fronts, pressure

systems, and isobars (top) and composite surface analysis which

adds radar and infrared satellite to show cloud cover (bottom).

For operations at nonaircraft ﬁ elds, special considerations

must be evaluated. Permission is necessary to use private

property as an airstrip. Locate the area on an aeronautical

sectional chart to check for possible airspace violations or

unusual hazards that could arise by not knowing the terrain

or location. Avoid loitering around residential structures and

animal enclosures because of the slow ﬂ ight characteristics

of WSC aircraft and distinct engine noise.

While selecting a takeoff position, make certain the approach

and takeoff paths are clear of other aircraft. Fences, power

lines, trees, buildings, and other obstacles should not be in the

immediate ﬂ ightpath unless the pilot is certain he or she is able

to safely clear them during takeoff and landing operations.

Walk the entire length of the intended takeoff and landing area

prior to departure. [Figure 5-3] Look for holes, muddy spots,

rocks, dips in the terrain, high grass, and other objects that can

cause problems during takeoff and landing. Physically mark

areas of concern with paint, ﬂ ags, or cones. Uneven ground,

mud, potholes, or items in ﬁ elds such as rocks might not be

visible from the air. Plowed rows and vegetation are larger

than they appear from the air. Unfamiliar ﬁ elds can make

suitable landing areas for emergencies, but should not be used

as intended landing areas. Extreme caution must be exercised

when operating from a new ﬁ eld or area for the ﬁ rst time.

Preﬂ ight Actions

A pilot must become familiar with all available information

concerning the ﬂ ight, including runway lengths at airport of

intended use, takeoff and landing distance accounting for

airport elevation and runway slope, aircraft gross weight,

wind, and temperature. For a cross-country ﬂ ight not in the

vicinity of the takeoff/departure airport, information must

include weather reports and forecasts, fuel requirements,

and alternatives available if the planned ﬂ ight cannot be

completed.

Weather

Weather is a determining factor for all ﬂ ight operations.

Before any ﬂ ight is considered, pilots should obtain regional

and local information to ﬁ rst determine if the predicted

weather for the planned ﬂ ight is safe.

Regional Weather

Understanding the overall weather in the region being

ﬂ own provides an overview of conditions and how they can

change during ﬂ ight. Fronts, pressure systems, isobars, and

the jet stream determine the weather. There are a number of

information resources from which to ﬁ nd the regional view

of weather systems, observed and predicted. Surface analysis

charts show these regional systems, which are common on

weather internet sites and TV broadcasts. [Figure 5-4] Review

the Pilot’s Handbook of Aeronautical Knowledge for a

comprehensive understanding of weather theory, reports,

forecasts, and charts for weather concepts covered throughout

this weather section.

There are many sources for obtaining a weather brieﬁ ng,

such as www.aviationweather.gov, www.nws.noaa.gov, 1-

800-WX-BRIEF, and a variety of internet sites that specialize

in local and regional weather.

COLD AIR BELOW

WARM AIR ABOVE

CALM BELOW

Turbulence where

the strong winds mix

with the calm air

STRONG WINDS ABOVE

Figure 5-5. Typical morning inversion layer—calm cold air is below; high winds are above.

Local Conditions

In gathering weather information for a ﬂ ight, obtain current

and forecast conditions where ﬂ ying, as well as alternate

airports in case landing at the intended destination is not

possible. These conditions should include wind (surface and

winds aloft), moisture, stability, and pressure.

Surface wind predictions and observations can be looked

at with a number of internet resources. The National

Weather Aviation service provides observations (METAR)

and forecasts (TAF) for areas with weather reporting

capabilities.

Winds aloft are forecast winds at higher altitudes than the

surface for locations throughout the United States. Refer

to the Pilot’s Handbook of Aeronautical Knowledge for an

understanding of the winds and temperatures aloft tables.

Winds aloft, too, are important for flight planning and

safety.

A typical situation during morning hours is cold air from the

night settling, creating calm winds at the surface with the

winds aloft (300 to 3,000 feet) at 30 knots. As the surface

begins to warm from the sun, the cold surface air starts to

warm and rise, allowing the high winds from above to mix

and lower to the surface. The wind sheer area in between the

high winds above and calm winds below is usually turbulent

and can overwhelm aircraft or pilot capabilities. Therefore,

it is a dangerous practice to look only at the wind sock for

surface winds when there could be strong winds above. Winds

aloft must be evaluated for safe ﬂ ight. [Figure 5-5]

During initial solo ﬂ ights, the wind should be relatively calm

to ﬂ y safely. As experience is gained, pilot wind limitations

can be increased. It is not until the pilot has had dual training

in crosswinds, bumpy conditions, and signiﬁ cant pilot in

command (PIC) time soloing in mild conditions that pilot

wind conditions should approach the aircraft limitations. A

safe pilot understands aircraft and personal limitations.

Moisture in the air has a signiﬁ cant effect on weather. If

the relative humidity is high, the chance of clouds forming

at lower altitudes is more likely. Clouds forming at lower

altitudes create visibility problems that can create Instrument

Meteorological Conditions (IMC) in which the visibility is

below that required for safe ﬂ ight. The temperature-dew point

spread is the basis for determining at what altitude moisture

condenses and clouds form. It is important to be particularly

watchful for low visibilities when the air and dew point

temperatures are within a spread of three to four degrees.

The closer these temperatures are to each other, the greater

the chance for fog or clouds forming with reduced visibility

conditions. Consider a scenario where the destination airport

currently has a temperature-dew point spread of 4 °F, and it

is evening when the atmosphere is cooling down. Since the

temperature-dew point convergence rate is 4.4° for every

thousand feet, the clouds/ceiling would be about 1,000

feet above ground level (AGL). Since it is cooling down,

the temperature-dew point spread is decreasing, lowering

the cloud level. Therefore, the 1,000 foot AGL ceiling is

lowering, creating IMC conditions that are not safe. For this

scenario, the ﬂ ight should not be attempted.

Air temperature and humidity directly affect the performance

of the WSC wing and engine. The higher the temperature,

humidity, and actual altitude of the operating ﬁ eld, the greater

role density altitude plays in determining how much runway

the WSC aircraft needs to get off the ground with the load

on board, and how much climb performance is required once

airborne. The WSC aircraft may have cleared the obstacle

at 8 a.m. when the weather conditions were cooler with less

humidity; at 1 p.m. with increased air temperature and higher

humidity levels, the pilot must reevaluate the performance

of that same aircraft. A full understanding of density altitude

is necessary to be a safe WSC pilot; refer to the Pilot’s

Handbook of Aeronautical Knowledge for density altitude

and weight effects on performance.

The rate of temperature decrease with increased altitude

determines the stability of the air. The stability of the air

determines the vertical air currents that develop during the

day as the area is heated by the sun. These rising vertical

air currents are commonly known as thermals. Generally,

stable air has mild thermals and therefore less turbulence

than unstable air. Unstable air rises faster, creating greater

turbulence. Highly unstable air rises rapidly and, with enough

moisture, can build into thunderstorms.

Air stability is easily determined by the rate at which the

temperature drops with increased altitude. A standard

atmosphere is where the temperature drops 2 °C for every

1,000 foot increase. If the temperature drops less than 2 °C

per thousand feet, the air is more stable with less vertical wind

(thermals) developed during the day. If the temperature drops

more than 2 °C per thousand feet, the air is more unstable

with more powerful vertical air currents developed during

the day, creating greater turbulence.

In addition to air stability, barometric pressure has a large

effect on weather. Low pressure in the area, below the

standard atmosphere of 29.92 "Hg, is generally rising air

with dynamic and unsettled weather. High pressure above

the standard atmosphere in the area is generally sinking air

resulting in good weather for ﬂ ying.

Many airports have automated weather systems in which

pilots can call the automated weather sensor platforms that

collect weather data at airports and listen to this information

via radio and/or land line. Radio frequencies are on the

sectional chart and the A/FD has the telephone numbers

for these stations. The systems currently available are the

Automated Surface Observing System (ASOS), Automated

Weather Sensor System (AWSS), and Automated Weather

Observation System (AWOS).

Local conditions of wind, moisture, stability, and barometric

pressure are factors that should be researched before ﬂ ight to

make a competent decision of go or no go to ﬂ y. High winds

and moist unstable air with a low barometric pressure indicate

undesirable ﬂ ying conditions. Light winds and dry stable air

with high pressure indicate favorable ﬂ ying conditions.

Pilots should research and document these local conditions

before ﬂ ight to predict the ﬂ ying conditions and compare

the actual ﬂ ying conditions to the predictions to learn and

develop knowledge from the information resources available

for ﬂ ight.

In addition to weather, the National Airspace needs to be

checked to ensure there are no temporary ﬂ ight restrictions

(TFR) for the locations planned to ﬂ y. TFRs may be found

at www.tfr.faa.gov/. For a complete preﬂ ight brieﬁ ng of

weather and TFRs, call 1-800-WX-BRIEF.

Clouds visually tell what the air is doing, which provides

valuable information for any flight. To understand the

different cloud formations and the ground/air effects

produced, refer to weather theory in the Pilot’s Handbook of

Aeronautical Knowledge. [Figure 5-6] Cloud clearance and

visibility should be maintained for the operations intended

to be conducted. The chapter covering the National Airspace

System (NAS) provides cloud clearance requirements in

each class of airspace. A pilot should not ﬂ y when ground

and ﬂ ight visibility are below minimums for his or her pilot

certiﬁ cate and the class of airspace where operating.

Knowledge of mechanical turbulence and how to determine

where it can occur is also important. The lee side of objects

can feel turbulence from the wind up to ten times the height

of the object. The stronger the wind is, the stronger the

turbulence is. [Figures 5-7 and 5-8]

In addition to adhering to the regulations and manufacturer

recommendations for weather conditions, it is important to

develop a set of personal minimums such as wind limitations,

time of day, and temperature-dew point spread. These

minimums will evolve as a pilot gains experience and are

also dependent on recency and currency in the make/model

of aircraft being ﬂ own.

I N DW

Figure 5-7. Turbulence created by manmade items.

Figure 5-6. Cloud diagram.

20,000 AGL

6,500 AGL

Low clouds

Middle clouds

High clouds

Nimbostratus

Altocumulus

Cirrostratus

Cirrocumulus

Cirrus

Altostratus

Stratus

Stratocumulus

Cumulus

Cumulonimbus

Clouds with vertical development

Figure 5-8. Turbulence created by natural land formations.

Figure 5-9. Enclosed trailer containing carriage and wing on top

of RV.

Weight and Loading

Weight and loading must be considered before each ﬂ ight.

Do not exceed the maximum gross weight as speciﬁ ed in the

pilot’s operating handbook (POH). The balance of the pilot,

passenger, fuel, and baggage is usually not an issue, but must

be reviewed in the POH for the speciﬁ c make/model since

some may have balance limitations. The fore and aft carriage

attachment to the wing hang point must be within the limits as

speciﬁ ed in the POH for weight and loading of the carriage.

Always follow the POH performance limitations.

Transporting

It is best to keep the WSC aircraft in an enclosed hangar, but

trailers may be used to transport, store, and retrieve the WSC

carriage. If the trailer is large enough, the wing can also ﬁ t

inside the trailer. If not, then it must ﬁ t on top of a trailer,

truck, or recreational vehicle (RV). [Figure 5-9]

Enclosed trailers are preferred so the carriage is protected

from the outside elements such as dust, rain, mud, road debris,

and the interested person who may want to tinker with the

carriage. The WSC carriage should ﬁ t snuggly without being

forced, be guarded against chaﬁ ng, and well secured within

any trailer. It is best to utilize hard points on the carriage

frame and secure each wheel so the carriage cannot move

fore and aft during transport. This is best accomplished by

ﬁ rst tying the front wheel from the axles, the fork, or a hard

point on the frame with a slight forward pull. Then, secure the

rear wheels from the axles or a hard point on the frame with

a slight rearward pull. Guides on the side of the wheels and

wheel chocks in front and back of each wheel are additionally

helpful to secure the carriage on any trailer.

The wing must have ample padding and should have at least

three support points where it rests for transport. Transporting

the wing properly is of critical importance because the wing

resting on any hard surface can wear a hole in the sail and

cause structural damage to the tubing. The greatest wear and

tear on a wing can occur during transportation. Each support

point should have equal pressure—no single point taking

most of the load. The wing should be tied down at each

attachment point to secure it, but not tight enough to damage

the wing. Wide straps are better than thin ropes because the

greater width creates less concentrated pressure on the wing

at each tie-down point.

Once the loading of the carriage and wing is complete

[Figure 5-9], take a short drive, stop, and check for rubbing

or chaﬁ ng of components.

Prior to taking the tow vehicle and trailer on the road, inspect

the tires for proper inﬂ ation and adequate tread. Ensure

all lights are operable, the hitch is free moving and well

lubricated, the tow vehicle attachment is rated for the weight

of the trailer, and the vehicle and trailer brakes are operable.

Avoid towing with too much or too little tongue weight,

which causes the trailer to ﬁ shtail at certain speeds, possibly

rendering it uncontrollable.

Be extremely cautious when unloading the wing and carriage.

This is best done with two people since the wing usually

weighs more than 100 pounds [Figure 5-10] and the carriage

Figure 5-13. Assembling control frame.

Figure 5-12. Wing cover bag unzipped, showing unique padding

around control frame corner brackets.

Figure 5-11. Wing positioned for setup.

Figure 5-10. Crane used for one person to lift 110-pound wing on

top of RV for transport.

usually must roll down some incline to get from the trailer

to the ground. Some carriages may be tail heavy without the

wing, and caution must be exercised, especially moving up and

down ramps. Check propeller clearance on the ground when

transitioning onto or off of a ramp and propeller clearance going

into and out of an enclosed trailer. If the carriage is transported

in an open trailer, it should be covered and the propeller secured

so it does not rotate/windmill during transport.

Setting Up the WSC Aircraft

Find a suitable area to set up the wing, such as grass,

cement, or pavement out of the wind. Inside a large hangar

is preferable since wind gusts are not a problem. If setting

up outside, align the wing perpendicular to the wind.

Most wings set up with the same basic procedure shown

in Figures 5-11 through 5-33, but the POH should be

referenced for the speciﬁ c WSC aircraft.

Rotate the wing bag so the zipper is facing up. [Figure 5-11] Unzip

the bag. When setting up the wing, pay close attention to

the specific pads, where they are located, and how they

are attached for each component of the wing. As shown in

Figure 5-12, the padding is made specifically for the control

frame between the downtubes and the control bar. If every

pad is not utilized when taking it down and transporting, there

will be wear on components with cosmetic and/or structural

damage to the wing. The POH may specify where pads go

during the setup and takedown. However, when setting up

Chapter 5 — Preflight and Ground Operations — Part 1