Mountain Flying

by K. Truemper

Acknowledgment: We thank Darrel Watson very much. He reviewed a first draft and

suggested a number of improvements.

Each time I plan a flight to the Rocky Mountains and beyond, I think “Now, what

are the important things to consider when flying into mountainous areas?” and then,

“Wouldn’t it be nice if I had a summary of those things for review!” So, here is an attempt

at such a summary. It is based on many sources: flight instructors, fellow pilots, various

has had an impressive way of teaching me lessons.

The discussion below introduces some formulas that I have found useful. If you hate

mathematics and formulas, just ignore that stuff. For me, doing these computations while

flying is a way to stay alert and to have something to talk about with my copilot.

1. Takeoff

1.1 Density Altitude

We must know the density altitude to estimate the minimum runway length required

for takeoff. An approximate formula for density altitude is

D = A + (T/20) + (A/4) - 3

where

D = density altitude in 1,000 ft

A = altitude in 1,000 ft MSL

T = temperature in deg F

For example, if A = 6 (= 6,000 ft) and T = 80 (= 80 deg F), then D = 6 + (80/20)

+ (6/4) - 3 = 8.5 (= 8,500 ft).

A more precise formula would use the pressure altitude P instead of A. To compute

P, we subtract from A 1,000 ft for each inch of pressure setting above 29.92, and add to

A 1,000 ft for each inch below 29.92. This correction is rarely needed, though, since the

pressure setting typically lies in the interval 29.6-30.2 in., and P and A differ then by less

than 300 ft.

A deceptively low density altitude occurs sometimes in the summer before sunrise.

Due to radiation cooling of a clear night, the surface air is cool, but from 500 ft AGL on

up the air is still hot. This phenomenon is typical for the southern Rockies, but may occur

as far north as Montana. I have seen 60 deg F at the surface and 95 deg F at 500 ft AGL.

In such a case, the high density altitude from 500 ft AGL on up significantly reduces the

climb performance of the airplane right after takeoff.

1.2 Leaning of Mixture

If the plane has a carburetor without automatic altitude compensation, leaning of the

mixture for maximum engine output is essential when the density altitude exceeds 5,000

ft. Just before takeoff, we go to full power while holding the plane with the brakes, adjust

the mixture until maximum rpm is obtained, then release the brakes and begin the takeoff

run. Below 5,000 ft density altitude, leaning is not needed, and is even dangerous, since

the engine may overheat during the climb out. As an aside, leaning should be done en

route below 5,000 ft density altitude whenever the power setting is 75% or less, and should

always be used above 5,000 ft density altitude regardless of power setting. The leaning is

done so that the engine is smooth and gives maximum rpm for the given throttle position,

and so that any additional leaning would disturb that performance.

1.3 Sudden Weather Changes in the Morning

A sunrise with a clear sky and with unrestricted visibility usually promises perfect

VFR conditions for the morning flight. Usually—but not always. Indeed, rapid fog development

and cloud formation shortly after sunrise may within 30 minutes turn that scenario

into IFR IMC. The spread between the air temperature and the dew point plus the surface

winds are the best predictors for this potentially dangerous development. Any spread less

than 5 deg F at sunrise combined with surface winds below 5 kts is cause for concern.

When the spread is 1 or 2 deg F, then the problem is almost certain to occur. On the

other hand, when the spread between the air temperature and the dew point is more than

3 deg F and surface winds exceed 5 kts, fog should not be a problem. However, in that

scenario clouds may still form rapidly unless the spread exceeds 5 deg F.

The solution to the problem is simple. We do not take off at sunrise when a potentially

troublesome situation is at hand, and instead monitor how things develop. If clouds and

fog do not set in for an hour while the air temperature rises and the spread increases, the

weather apparently is stable, and a takeoff is justified. On the other hand, if low areas

develop fog or if mountain ridges begin to spawn cloud cover, we stay on the ground until

stable VFR conditions return.

2. En Route Flying

2.1 Ceiling of Plane

The legal limit for flight without oxygen or pressurization is 12,500 ft MSL. That

limit may be exceeded up to 14,000 ft MSL for up to 30 min. Naively, we may therefore

conclude that a plane with a published ceiling of 14,000 ft can take advantage of these

limits. But this is not so. First, a plane’s ceiling is the density altitude where the climb

rate at full power begins to fall below 100 ft/min. This is a very low climb rate. A better

figure for the ceiling is the published ceiling minus 1,000 ft. So, a ceiling of 14,000 ft has

become 13,000 ft. Suppose we fly eastbound, where we must elect odd-thousand-plus-500

ft as MSL altitude. Say we choose 11,500 ft MSL. If the temperature at that altitude is 50

deg F, a typical value for the Rockies in the summer, then the density altitude is D = 11.5

+ (50/20) + (11.5/4) - 3 = 13.9 (= 13,900 ft), which is above the 13,000 ft the plane can

reasonably reach. Hence, we are forced to the next lower altitude, 9,500 ft MSL, which is

too low for many regions of the Rockies. This example shows that a plane with published

14,000 ft ceiling is unsuitable for flight in the Rockies in the summer. On the other hand,

a bit of calculations shows that a plane with a published 17,000 ft ceiling manages to reach

altitudes up to 13,500 ft MSL in the Rockies in the summer, within reasonable time, unless

temperatures are unusually high.

A normally aspirated piston engine loses power by about 3.5% for every 1,000 ft of

density altitude. The formula below expresses this relationship.

PD = [1 - 0.035D]P

where

D = density altitude in 1,000 ft

PD = maximum power output in hp at density altitude D

P = maximum power output in hp at sea level

For example, if D = 12 (= 12,000 ft) and P = 100 (= 100 hp), then PD = [1 -

(0.035)(12)]100 = 58 (= 58 hp).

If the propeller is not in-flight adjustable, the maximum engine output at altitude

may no longer be sufficient to maintain cruise rpm. When that happens, the output is

reduced below PD of the formula. To compute engine output for the reduced rpm, we

apply the above formula for PD using as P the maximum output of the engine for the

reduced rpm at sea level. For example, Rotax publishes 76 hp for the 912UL engine as

maximum continuous output at 5,400 rpm, and 64 hp as maximum output at 4,400 rpm.

Suppose at 14,500 ft density altitude the maximum rpm with full throttle is held to 4,400

rpm due to the propeller pitch. Using P = 64 and D = 14.5, the output for that density

altitude and rpm is PD = [1 - (0.035)(14.5)]64 = 31.5 hp. On the other hand, if the

propeller is repitched so that the engine can turn 5,400 rpm at the same density altitude,

then P = 76 and PD = [1 - (0.035)(14.5)]76 = 37.4 hp, an increase of 19%. That increase

could be realized if the propeller was in-flight adjustable. Hence, such a propeller can be

advantageous even if the engine is normally aspirated.

2.2 Turbulence

An important predictor of severe turbulence is the wind aloft just above the mountains.

When that wind exceeds 25 kts, flying can be extremely dangerous since turbulence may

invert the plane. If such winds are approximately (= plus or minus 30 deg) perpendicular

to mountain ridges, then they produce mountain wave conditions and turbulence up to 100

miles downwind from the mountains. Hence, if winds above 25 kts are forecast, we should

not fly near mountains, and if we are downwind from mountains, we should not approach

them.

Another predictor of turbulence is the temperature lapse rate, measured in deg F/1,000

ft of altitude change. A lapse rate below 4 deg F/1,000 ft signals stable air. When the

lapse rate rises beyond 4 deg F/1,000 ft, turbulence can be expected. The severity depends

on how far the lapse rate is above 4 deg F/1,000 ft. For example, a rate of 6 deg F/1,000 ft

is associated with strong turbulence. We can anticipate potentially troublesome situations

by computing the lapse rate as we climb. The formula for the lapse rate is

L = [TG - TA]/[A - G]

where

L = lapse rate in deg F/1,000 ft

A = altitude in 1,000 ft MSL

G = ground elevation in 1,000 ft MSL

TA = temperature at altitude A in deg F

TG = temperature at ground elevation in deg F

For example, if A = 9.5 (= 9,500 ft), G = 4.5 (= 4,500 ft), TA = 70 (= 70 deg F),

and TG = 100 (= 100 deg F), then L = [100 - 70]/[9.5 - 4.5] = 6, and severe turbulence

is present.

The turbulence induced by the lapse rate stops at the base of clouds. Hence, if cumulus

clouds are sufficiently low and widely spaced to permit safe VFR above the clouds, we can

elect that option for a much smoother flight. We must exercise caution, though. Cumulus

clouds in mountainous areas may within minutes grow to a solid cover, so when flying

above such clouds we should continuously monitor the situation and be prepared for a

rapid descent below clouds that are closing up.

Certain cloud formations are telltale signs of strong turbulence. A rotor cloud, which

is a small, round cloud downwind of and slightly higher than a mountain ridge or peak,

indicates severe turbulence and must be avoided at all times. Lenticular clouds, which

have the shape of a lens, by themselves indicate smooth airflow at the altitude of the

clouds, but signal strong turbulence below them. Fuzzy, streaky, torn clouds above a ridge

are a third indicator of severe turbulence. Cumulus clouds with veils below that do not

extend to the ground send yet another message of strong turbulence. The veil is called

virga and is rain that evaporates before reaching the ground. Virga clouds can turn into

thunderstorms within minutes, so we should monitor them continuously.

Thunderstorms in mountainous terrain can be very violent. They typically produce

extensive lightning, strong downpours, severe turbulence, and often hail. A respectful

distance of at least 20, and preferably 30, miles should be kept.

A flight started early in the morning usually begins with a smooth ride. As the air

warms and winds increase, turbulence sets in. Around noon, the turbulence typically has

become so strong that the flight should be terminated. For the latest, we should stop at

1 pm. There are exceptions where the air is still smooth after 1 pm and where flying is

still safe. But we should carefully consider winds, terrain, and weather before claiming

that this unusual case is hand. If we miscalculate, then in the best of cases we have an

uncomfortable flight. In the worst of cases, passengers toss their cookies, the flight becomes

almost uncontrollable, and possibly metal is bent in an unintended termination.

2.3 Winds

When air moves up due to sloping terrain, say toward a mountain ridge, the air

remains mostly smooth and provides an updraft. However, on the lee side of the ridge, the

air becomes a turbulent downdraft with a rate of descent that may exceed the maximum

climb rate of the plane. When planning the route, we should therefore take both the

direction of the winds aloft and the terrain into account. If the route can be planned along

the upwind side of a ridge, then the flight is smooth, and the updraft provides extra energy

that can be converted into added speed. On the other hand, if the route by necessity is on

the lee side of a mountain or ridge, we must fly at least 2,000 ft above the highest point

of the terrain to avoid strong down drafts and turbulence.

We should never approach a mountain ridge at a right angle. If turbulence is encountered

and we must turn back, then in the first part of the turn we get even closer to the

ridge and thus into more severe turbulence, and possibly begin unplanned inverted flight.

This dangerous scenario can be avoided by approaching the ridge at a shallow angle not

exceeding 45 deg. If turbulence is encountered, we can turn away from the ridge without

first getting closer.

We should avoid flight in valleys since by definition this moves us well below the

surrounding mountain ridges. But sometimes that is not an option. For example, we may

have to enter a valley to approach an airport. In that case, we should always stay near

the mountain ridge that forces the wind up, and should avoid the center of the valley as

well as the ridge with the downdraft. It is clear why we should avoid the ridge with the

downdraft, but why should we shun the center of the valley as well? If we fly there, we

do not have a good look at the valley below for emergency landing sites, and we may have

difficulty turning if unexpected turbulence forces us to do so.

2.4 Restricted Areas and Military Operations Areas (MOAs)

Restricted areas are off-limit for general aviation, and we must stay clear of them

at all times. In recent years, restricted areas have moved or changed shape, and a GPS

radio with last year’s or older database does not reliably indicate the current restricted

areas. Hence, unless the database contains the most recent information, we can only use

the sectional to identify and avoid restricted areas. A recent development are small, round

restricted areas of 5-10 miles diameter. They contain tethered balloons. Entering such an

area is likely to terminate the flight by collision with the balloon cable.

MOAs legally pose no restriction for general aviation. But when an MOA is “hot,”

that is, in use, we assume a great risk when entering it. The sectionals have rather imprecise

information about MOAs, since they typically specify sunrise to sunset for certain days of

the week as possible times of use. During those specified times the MOA may or may not

be hot. We just cannot tell which is the case from the sectional. But we can get precise

information from the nearest FSS.

Recently, sectionals have begun to provide contact frequencies for some MOAs that

result in something akin to flight into C space. We declare the intentions, are assigned a

transponder code, and follow the instructions of the military controller. We should make

sure to request permission for any deviation from the assigned altitude or course. Just

telling the controller the entire planned route through the MOA at the first contact is not

good enough. Another recent development are grey-shaded Special Military Activity areas.

For transit, we must establish contact on the frequency listed on the sectional unless we

desire to be mistaken for a drug runner.

2.5 Endurance

The legally required minimum endurance for day VFR, which is 30 min beyond the

destination airport, is not even close to sufficient, due to the vagaries of mountain weather

and winds. A good rule is 1 hr of fuel beyond the planned flight time, and 1 1/2 hrs if the

route has few nearby alternate landing sites or if the weather is potentially unstable.

3. Landing

3.1 Turbulence

It is rare that the approach to landing does not encounter some turbulence. To minimize

the effect, we should plan a comparatively steep descent to the destination airport.

Such an approach also provides a good overview over the terrain near the airport.

3.2. Traffic Pattern

At uncontrolled airports in mountainous terrain, we should not expect pilots to adhere

to the published traffic pattern. Instead, we should count on any pattern, on any entry,

and even on use of runways in both directions. The key to a safe approach and landing

is monitoring of the traffic frequency, repeated broadcast of our position, and watching,

watching, watching for traffic. Even on the ground, we should announce all steps such as

clearing the runway or taxiing across another runway, due to the topsy-turvy way runways

are sometimes used.

3.3 Landing Speed

When the density altitude of the airport is high, the groundspeed during landing is

well above the indicated airspeed. When in that situation a gust factor is added to the

indicated airspeed due to shifting winds, the groundspeed at the moment of touchdown

becomes even higher. Thus, slowing the plane down after touchdown may require an

extended rollout. For example, suppose the density altitude of the airport is 9,500 ft. If

the landing speed is 50 kts plus a 5 kts gust factor, then, according to the formula for TAS

given in the next section, the indicated airspeed IAS of 55 kts represents a true speed TAS

= [1 + ((1.5)(9.5)/100)]55 = 63 (= 63 kts). Suppose we have a 10 kts headwind as we

land. Then we touch down with a groundspeed of 63 - 10 = 53 kts. In contrast, a normal

landing speed of 50 kts in smooth air, at sea level, and with a 10 kts headwind produces a

groundspeed of 50 - 10 = 40 kts. Effectively, the normal landing groundspeed of 40 kts in

smooth air at sea level has become 53 kts. Since the kinetic energy of the plane increases

with the square of the groundspeed, the energy that must be dissipated during the rollout

by the drag of the airplane and by the brakes, is increased by 76%. Thus, the rollout is

much longer than usual.

4. Two More Formulas

Here are two additional simple formulas. They give reasonable estimates for the true

airspeed and the course correction for crosswind. En route, we can compare the true

airspeed with the groundspeed displayed by the GPS radio to get an idea how far forecast

winds aloft differ from actual winds. The course correction formula comes in handy during

flight planning.

4.1 True Airspeed

Up to 15,000 ft density altitude, true airspeed is larger than indicated airspeed by

approximately 1.5% for each 1,000 ft of density altitude. The formula below expresses this

relationship.

TAS = [1 + (1.5D/100)]IAS

where

TAS = true airspeed in kts

IAS = indicated airspeed in kts

D = density altitude in 1,000 ft

For example, if IAS = 95 (= 95 kts) and D = 10 (= 10,000 ft), then TAS = [1 +

((1.5)(10)/100)]95 = 109 (= 109 kts).

4.2 Crosswind Correction

The magnetic heading is the magnetic course plus or minus the course correction for

crosswind. That correction, in deg, can be estimated as follows.

CC = CW/K

where

CW = crosswind in kts

K = factor depending on plane speed

(K = 2 for 100 kts; K = 3 for 150 kts, K = 4 for 200 kts)

For example, if the crosswind is CW = 10 (=10 kts) and the plane does 100 kts, then

K = 2, and CC = 10/2 = 5 (= 5 deg) is the correction for the crosswind.

This is the end of the summary. I have tried to cover the most important aspects of

safe summer flying in mountainous terrain. But the summary is not complete: It does not

tell about the excitement of an early morning takeoff from a mesa into a clear sky, with

mountain tops tinged red by the first rays of the sun and with dark valleys below; does not

speak of the peace and serenity of a midmorning flight across a majestic mountain range

topped with snow. And does not even mention the great feeling of a slow descent into an

airport nestled on a picturesque mountain side, with friendly FBO folks and fellow pilots

just waiting for us to land and visit and talk. Talk about what? About flying, of course!

Flying Around Thunderstorms

by K. Truemper

Flying to Oshkosh this year with my friend A. Tamir, we stopped in the early afternoon

at Cassville, MO, due to deteriorating weather that spawned thunderstorms. Another plane

landed shortly after us. The pilot told us he was coming from Oshkosh, had flown in parts

of Missouri at 200 ft AGL, and was planning to go on to Texas. Indeed, he added some oil

to the engine and proceeded to take off into deteriorating weather. Maybe he was lucky

and did make it home that day. But one would not call his decisions prudent or safe. How

can we deal with thunderstorms safely? It depends on the circumstances.

A Model for Thunderstorms

Imagine a pot of water that is being heated on a stove and is close to the boiling point.

Now and then a bubble of steam forms at the bottom of the pot, rises, and breaks up as it

reaches the surface of the water. Keep that picture in mind when analyzing thunderstorms.

The hot water represents hot, muggy air, and each rising bubble corresponds to the rising

column of air inside a thunderstorm cell.

When the water in the pot reaches the boiling point, suddenly bubbles rise everywhere.

In the corresponding situation, a megasystem of thunderstorms is produced within minutes.

On radar, a large area turns yellow (= heavy rain, turbulence), while the rest is green

(= rain). Never, ever fly in such weather because it is almost impossible to survive the

accompanying windshear of microbursts, the deluge of rain, the lightning, and the possibly

occurring hail. Warning signals for this setting are high temperatures, close to 100%

humidity, and very strong surface winds. I have seen that setting turn into a cauldron

of thunderstorms within 15 minutes, with 40 kt surface winds changing direction by 180

degrees in 20 seconds as a microburst came down on the airport. At that time, I was a

low-time pilot, and by sheer luck had landed 10 minutes earlier, learning the lesson while

on the ground.

A more benign setting involves well-defined fronts whose movement is controlled by

high/low pressure systems. Such a front may continuously change shape, spawn thunderstorms,

rain, and even hail. But the movement is predictable, and the cells start, grow,

and eventually dissipate in a time frame that allows evasive maneuvers. DTN, now available

at most airports, is the best tool for analyzing such weather. You can get the same

information at home by going to the AOPA website.

Making Good Decisions

An experienced pilot once told me that he never flies IFR in such a situation since

he may inadvertently blunder into a cell, not having radar or a Stormscope on board.

So, VFR is advisable even if you are IFR rated. Unless, of course, you have appropriate

detection equipment on board. So, let us assume that you plan to fly VFR, as most of us

must anyway.

When you contact a Flight Service Station (FSS) while on the ground, the briefer

usually paints a gloomy picture that makes flight look like a life-threatening undertaking.

The reason for that gloom is liability. No plane has ever crashed when the pilot chose to

stay on the ground. So it is up to you to decide which part of the weather is reasonably

benign and which is potentially dangerous. This decision may be difficult. It becomes

easier if you look at the DTN radar picture while talking with the briefer. Suppose you

decide to go. You have one or more of the following problems to contend with: low ceilings,

rain with low visibility, hail, turbulence, and lightning.

Low Ceilings

Flying while ceilings come down more and more until you are squeezed at 200 AGL

between ceiling and ground is a very bad decision. You must have criteria that absolutely

rule out that terrifying scenario. The criteria must be based on two considerations: the

altitude rules for VFR and the uncertainties of weather. Let us look at these two aspects.

A veritable maze of VFR regulations concerns flight over densely populated areas, near

clouds, and into various classes of air space. One could work out the altitude restrictions

for each of the numerous cases. A bit more stringent but workable for flight with reduced

ceilings are the following three altitude rules, which assume that flight is below 10,000 ft

MSL.

Three Altitude Rules

1. Never take off with a ceiling of less than 2000 ft.

2. During flight, if the ceiling becomes 2000 ft or less, fly 500 ft below the ceiling.

3. Land before the ceiling goes below 1500 ft.

Suppose the ceiling is 2000 ft. By rule #2, you should fly at 1500 ft AGL. That

altitude places you below the tops of a number of towers, so careful planning of the route

and precise navigation are needed. Suppose the ceiling goes down to 1500 ft. By rule #2,

you are at 1000 ft AGL and can land at any controlled or uncontrolled airport, assuming

that visibility is at least 3 miles; we discuss the visibility aspect in detail in a moment.

Here is an example how easily you can get stuck if you do not observe rule #3.

Suppose the ceiling is 1300 ft and going down, and the closest airport is uncontrolled and

in a densely populated area. A magenta area with 10 mile radius encloses the airport. You

cannot legally land at that airport for the following reasons. (1) The magenta area means

that above 700 ft AGL, you must be at least 500 feet below the ceiling. Thus you cannot

be above 800 ft AGL when in that area. (2) The densely populated area means that you

must be at least 1000 ft AGL unless landing. You cannot claim a 10 mile final to overcome

condition (2), so the airport cannot be used.

Uncertainties of Weather

To account for the vagaries of weather, select the route so that airports occur in close

spacing, one after another, even if this means detours. Let me call such flying from one

potential landing site to the next one “airport hopping.”

As you hop from one airport to the next, look up the data for that next airport and

record them on your pad. Monitor ATIS, ASOS, and AWOS frequencies so that you can

update the altimeter and are aware of surface winds. Then, if you must land, you can do

so quickly and safely.

Continuously monitor the ceiling ahead of you and behind you so that you become

aware of potential problems before they become serious. Return to the most recently

passed airport or go to the next one before the ceiling goes below 1500 ft and you get

squeezed between a low ceiling and the ground. Do not try to avoid low ceilings in front

of you by turning left or right from your course. When such maneuvers become necessary,

it is time to turn back and land as soon as possible. Indeed, any detour likely traps you

by a low ceiling with no airport nearby.

Rain

VFR requires visibility of 3 miles or better if you adhere to the rules above about

ceilings. This means that VFR in rain is possible only if the rain is light to moderate.

There is another reason for accepting nothing more than moderate rain. In heavy rain you

may blunder into a cell, at which point survival is questionable. So, never ever allow rain

to reduce visibility below 3 miles. If necessary, detour around areas of heavy rain. But

do this only if the ceiling is not marginal, since otherwise you may get trapped by a low

ceiling while evading heavy rain.

Hail

While rain hitting the thin skin of the airplane may sound like hail, do not worry. If

it is hail, you will know the difference. Seriously, you avoid hail by staying at least 15-20

miles away from cells.

Turbulence

Watch our for clouds with hanging curtains that do not reach the ground. This is rain

that evaporates in the air and is called virga. That setting guarantees moderate to heavy

turbulence, so you must stay away. The same applies to turbulence spawned by cells.

Thunderstorm Cells

If cells are isolated and not hidden by other clouds, you just fly around them, keeping

a respectful distance of 15-20 miles. This situation occurs often in the Southwest and

West. But elsewhere, cells often are surrounded by clouds, and ceilings are less than 5000

ft and often 2000-3000 ft. In that case, stay below all clouds and clear of any heavy rain.

The warning sign of a cell is a dark mass of rain that extends from the lowest cloud layer

to the ground, thus obscuring the horizon. That dark mass may only be rain, but you

cannot tell. So always assume that it contains a cell.

If there is just one such dark mass, maneuver around it, keeping a 15-20 mile distance

if possible, but certainly no less than 10 miles, to avoid the possibly severe turbulence

associated with that dark mass. Cells typically move at no more than 40 kts, and often at

much slower speed. But when entering the mature stage, a cell may suddenly expand at a

huge speed and be on top of you. At that time, you cannot outrun the cell. This is another

reason for the recommended distance of 15-20 miles. A third reason is that sometimes a

cell pitches hail from the top that may come down several miles away.

Contact with FSS

The discussion so far has centered on your decisions. But while you fly along and

evaluate the situation, you should be in frequent contact with FSS to get updates and

advice. Such contact is vitally important when several dark masses, and thus potentially

several cells, show up. You should not try to select a route without FSS assistance, since

you may get trapped with cells in all four quadrants and no airport in sight.

Contacting FSS while flying low is often difficult. At least I thought so until recently.

First, Flight Watch 122.0 is the preferred frequency. But unless you are near an outlet,

you get no response when flying at or below 3000 ft AGL. Second, most VORs no longer

carry voice, and the VOR boxes on the sectional often do not list other voice frequencies.

Thus, a near VOR may not be of help either. So how do you contact FSS? Recently, I

realized that I should use the AOPA Airport Directory to look up the data for the airport

closest to my position. The data include a FSS frequency that normally is used to open

and close flight plans. That frequency often is not listed on the sectional. But it is almost

guaranteed to work, even when you fly 2000 ft AGL. The briefer may refer you to Flight

Watch 122.0, but when you explain that you have not been able to establish contact, you

will get help. Give the briefer your present position using the nearest VOR (radial and

distance – the GPS radio has this information readily available) as well as altitude and

direction of flight. The briefer will explain what you are facing. Do not hesitate to ask for

clarification. For example, asking “Will I avoid all cells if I go north for 30 miles and then

turn west?” is a good way to clarify whether you have fully understood the situation laid

out by the briefer.

Psychological Component

Up to this point, we have covered technical aspects. But there is also an important

psychological component that we should take into account. Part of that component is our

innate determination to reach goals that we have set for ourselves. Here, it means that

we pressure ourselves to reach the destination planned for the day. This pressure, if not

controlled, can lead to continued flight into worsening weather, and we may go way beyond

the limits that we set initially for ourselves and end up flying VFR into IMC (instrument

meteorological conditions).

How can we counteract that urge to continue when we should stop? There are two

remedies. The first one says that we should stick to the following two rules.

Two Rules for Flight Planning

1. Depart as early in the morning as is permitted for daytime VFR, which is up to

30 min prior to sunrise. For me, it is too dark at that time, and I favor 15 min prior to

sunrise. In the summer, this means a takeoff before 6 am.

2. Select a destination for the day that can be reached by 1 pm at the latest, assuming

that the weather fully cooperates.

If the takeoff is at 6 am, rule #2 allows for a travel time of 7 hours, which translates to

two 3 hr legs and a 1 hr break for refueling and relaxing. Suppose the weather deteriorates

at, say, 11 am. At that time, we are 1 hour into the second leg, and there are 2 hours left

to fly. We tell ourselves “There is plenty of time left in the day to do 2 hours of flying, so

let’s take it easy and not press forward,” and thus remove the internal pressure to go on.

On the other hand, if the weather cooperates till we have completed the second leg,

we can optionally extend our schedule. If the weather deteriorates during that optional

third leg, we tell ourselves “We have already achieved more than we had planned, so let’s

stop and enjoy the rest of the day on the ground.”

The second remedy I learned from Don Christianson. As the weather becomes more

and more ominous and we feel the urge to continue the flight, we tell ourselves repeatedly

“Is this really the day I want to die?” Once we have repeated this question a few times

like a mantra, our brain becomes aware that there is more to life than pressing on to the

planned destination, and it begins to make sensible decisions like landing at the closest

airport.

Belief in Persistence of Present Conditions

There is a second psychological aspect that works against us. It is our belief that

things will continue to be the way they are now. As we see poor but acceptable weather

around us, we tend to believe that it will persist that way for miles ahead. But if anything

is not constant, it is weather. If the weather is bad, we should not tell ourselves “This

is not great, but good enough to continue.” Instead, we should say “This is bad, let’s be

cautious and make sure we do not get trapped if it deteriorates.” A short version that can

be used as a mantra, is “This is bad weather; we must be very careful.”

The belief in persistence of the present situation has another undesirable effect. Once

we have landed due to bad weather, we may believe that bad weather will continue for the

rest of the day and check into a motel right then and there. If we departed at 6 am as

suggested, the landing due to bad weather takes place in the morning or at most around

noon, and there is lots of time left for the weather to improve. I have found a number of

times that dismal weather often improves around 4 to 5 pm and stays fair at least into

the early evening. So, if we take off at 5 pm, we may well have another 2-3 hours of flying

time left, which usually suffices to reach the planned destination.

The rules for coping with the psychological component are then as follows.

Rules for Handling Psychological Component

1. Leave as early as daytime VFR allows.

2. Select a destination that under normal circumstances can be reached by 1 pm.

3. Two mantras for deteriorating weather: “This is bad weather; we must be very

careful” and “Is this really the day I want to die?”

If you follow the above rules, you can fly safely in difficult weather. On our Oshkosh

trip, we used these rules extensively. Except for one day when we were weathered in Osage

Beach, MO, we reached each destination as planned and without compromising safety.

While at Oshkosh, we learned that 13 people had died flying to or from Oshkosh. Given

the bad weather prevailing in the Midwest and elsewhere during that time, I suspect that

weather was at least partially a factor in many of these fatal accidents. We can do much,

much better, by using good decision procedures and safe practices.

7. Tasks that take time or are subject to

9. If you observe any obvious signs in