## A2-6 LANDING SITE WEATHER CRITERIA \[hc\] (continued) {#a2-6-landing-site-weather-criteria-hc-continued .Cont}

C. THUNDERSTORM, LIGHTNING, AND PRECIPITATION

### TABLE A2-6-III - THUNDERSTORM, LIGHTNING, AND PRECIPITATION

+-----------------+---------------+---------+---------+-------+---+------+
| **THUNDERSTORM, |               | **PREL  | **PREDE | *     | * |      |
| LIGHTNING, AND  |               | AUNCH** | ORBIT** | *REDE | * |      |
| PRECIPITATION   |               |         |         | SIG** | E |      |
| PROXIMITY       |               | *       | **      |       | L |      |
| LIMITS (NM)**   |               | *(RTLS, | (EOM,** | **    | S |      |
|                 |               | TAL)**  |         | CRITE | , |      |
|                 |               |         | **DAILY | RIA** | * |      |
|                 |               |         | PLS)**  |       | * |      |
|                 |               |         |         |       |   |      |
|                 |               |         | **PR    |       | * |      |
|                 |               |         | ELAUNCH |       | * |      |
|                 |               |         | (AOA)** |       | E |      |
|                 |               |         |         |       | C |      |
|                 |               |         |         |       | A |      |
|                 |               |         |         |       | L |      |
|                 |               |         |         |       | , |      |
|                 |               |         |         |       | * |      |
|                 |               |         |         |       | * |      |
|                 |               |         |         |       |   |      |
|                 |               |         |         |       | * |      |
|                 |               |         |         |       | * |      |
|                 |               |         |         |       | A |      |
|                 |               |         |         |       | C |      |
|                 |               |         |         |       | L |      |
|                 |               |         |         |       | S |      |
|                 |               |         |         |       | * |      |
|                 |               |         |         |       | * |      |
+=================+===============+=========+=========+=======+===+======+
|                 | RADIAL FROM   | \>20    | \>30    | \>15  |   | NONE |
|                 | CENTER OF     |         |         |       |   | AT   |
|                 | PRIME RUNWAY  |         |         |       |   | SITE |
+-----------------+---------------+---------+---------+-------+---+------+
| TSTORM          | LATERAL ALONG | \>10    | \>20    | \>5   |   |      |
| (including      | APPROACH PATH |         |         |       |   |      |
| attached        | OUT TO 30 NM  |         |         |       |   |      |
| nontrans-parent |               |         |         |       |   |      |
| anvils), and    |               |         |         |       |   |      |
| LIGHTNING       |               |         |         |       |   |      |
+-----------------+---------------+---------+---------+-------+---+------+
|                 | VERTICAL FROM | \>2     |         |       |   |      |
|                 | TOP OF CLOUD  |         |         |       |   |      |
+-----------------+---------------+---------+---------+-------+---+------+
|                 | RADIAL FROM   | \>15    | \>20    | \>15  |   | N/A  |
|                 | CENTER OF     |         |         |       |   |      |
|                 | PRIME RUNWAY  |         |         |       |   |      |
+-----------------+---------------+---------+---------+-------+---+------+
| DETACHED\       | LATERAL ALONG | \>5     | \>10    | \>5   |   |      |
| nontransparent  | APPROACH PATH |         |         |       |   |      |
| ANVIL           | OUT TO 30 NM  |         |         |       |   |      |
|                 |               |         |         |       |   |      |
| \< 3 HRS OLD    |               |         |         |       |   |      |
+-----------------+---------------+---------+---------+-------+---+------+
|                 | VERTICAL FROM | \>2     |         |       |   |      |
|                 | TOP OF CLOUD  |         |         |       |   |      |
+-----------------+---------------+---------+---------+-------+---+------+
|                 | RADIAL FROM   | \>20    | \>30    | \> 15 |   | N/A  |
|                 | CENTER OF     |         |         |       |   |      |
|                 | PRIME RUNWAY  |         |         |       |   |      |
+-----------------+---------------+---------+---------+-------+---+------+
| pRECIPITATION   | LATERAL ALONG | \>10    | \>20    | \> 5  |   |      |
| \*              | APPROACH PATH |         |         |       |   |      |
|                 | OUT TO 30 NM  |         |         |       |   |      |
+-----------------+---------------+---------+---------+-------+---+------+
|                 | VERTICAL FROM | \>2     |         |       |   |      |
|                 | TOP OF CLOUD  |         |         |       |   |      |
+-----------------+---------------+---------+---------+-------+---+------+
| Cumulus clouds  | Lateral along | \>0     |         |       |   | N/A  |
| produced by     | approach path |         |         |       |   |      |
| smoke/fire up   |               |         |         |       |   |      |
| to 1 hr after   |               |         |         |       |   |      |
| detaching       |               |         |         |       |   |      |
+-----------------+---------------+---------+---------+-------+---+------+

\* EXCEPTIONS EXIST FOR RTLS, SEE rule {A2-6C}.3, landing site weather
criteria \[HC\]. ®\[111298-6734 \] ®\[ED          \]

1\. THUNDERSTORMS (INCLUDING ATTACHED NONTRANSPARENT ANVILS), LIGHTNING,
DETACHED nONTRANSPARENT ANVILS LESS THAN 3 HOURS OLD, OR PRECIPITATION
MUST BE OUTSIDE THE LIMITS LISTED IN TABLE A2-6-iii TO ENSURE WEATHER
DOES NOT ADVERSELY EFFECT THE ORBITER DURING AN ENTRY AND LANDING. THE
LATERAL OR VERTICAL LIMITS MUST BE MET IN ADDITION TO THE RADIAL LIMIT.
®\[ED          \] ®\[111298-6734 \] ®\[022604-6167A\]

a\. RADIAL PROXIMITY LIMITS ARE RELATIVE TO THE CENTER OF THE PRIME
RUNWAY. ®\[111094-1622B\]

## This Rule Continued on Next Page  {#this-rule-continued-on-next-page .Cont}

## A2-6 LANDING SITE WEATHER CRITERIA \[HC\] (continued) {#a2-6-landing-site-weather-criteria-hc-continued-1 .Cont}

b\. LATERAL PROXIMITY LIMITS ARE RELATIVE TO THE ORBITER APPROACH PATH
OUT TO A RANGE OF 30 NM FROM THE CENTER OF THE PRIME RUNWAY.
®\[111094-1622B\]

c\. VERTICAL CLEARANCES ARE FROM THE TOP OF THE THUNDERSTORM OR SHOWER
TO THE ORBITER APPROACH PATH.

2\. FOR acls/ECAL/ELS, PRECIPITATION IS ACCEPTABLE. NO THUNDERSTORMS
(INCLUDING ATTACHED NONTRANSPARENT ANVIL) OR LIGHTNING AT THE SITE.
®\[020196-1808A\] ®\[111298-6734 \] ®\[022604-6167A\]

3\. FOR RTLS and tal, RAIN SHOWERS (excluding cumulonimbus) WITHIN THE
LIMITS LISTED ABOVE ARE ACCEPTABLE IF ALL OF THE FOLLOWING CONDITIONS
ARE MET: ®\[021998-6490A\] ®\[022604-6167A\] ®\[121604-6533A\]

a\. ADEQUATE SATELLITE, RADAR, AND AIRCRAFT SURVEILLANCE are AVAILABLE.

b\. NO SUBSTANTIAL INCREASE IN EITHER COVERAGE OR INTENSITY IS FORECAST.

c\. the OBSERVED AND FORECAST HORIZONTAL MOVEMENT of individual
rainshowers and other weather features IS LINEAR OR NEAR LINEAR.

d\. RULE {A4-111}, runway acceptability conditions, IS observed "go" and
forecast to remain "GO". ®\[021998-6490A\] ®\[121604-6533A\]

## This Rule Continued on Next Page  {#this-rule-continued-on-next-page-1 .Cont}

## A2-6 LANDING SITE WEATHER CRITERIA \[hc\] (continued) {#a2-6-landing-site-weather-criteria-hc-continued-2 .Cont}

e\. FOR A MINIMUM OF TWO APPROACHES, THE ORBITER ®\[021998-6490A\]
®\[121604-6533A\]

\(1\) SHAll not fly through precipitation, and

\(2\) can maintain either a 10-nm lateral clearance or a 2-nm vertical
clearance from any shower that:

\(a\) has moderate or greater precipitation, or

\(b\) has a cloud top temperature colder than +5 degrees celSius, or

\(c\) Has had a cloud top temperature colder than -10 degrees celSius
within 2.5 hours prior to launch. ®\[121604-6533A\]

4\. The orbiter shall not penetrate a cumulus cloud that is attached to
a smoke plume produced by a fire. if the cumulus cloud detaches from the
smoke plume, 1 hour must elapse from time of detachment for safe
penetration by the orbiter. ®\[111298-6734 \] ®\[022604-6167A\]

The orbiter is not to encounter precipitation on any approach due to
decreased visibility, damage to the TPS, and the potential for triggered
lightning. Undesirable aspects of thunderstorms include rain (TPS,
structure), hail (TPS, structure, control), severe wind shear
(structure), turbulence (control, performance, structure), and natural
or triggered lightning (structure, electronic/software systems).
Environmental design requirements for the orbiter are based on no
in-flight penetration of thunderstorms (ref. Appendix 10-10, Volume X,
Space Shuttle Level II Program Specification). The participants in the
Weather Rules Workshop held at JSC/MSFC in October 1987 developed the
thunderstorm, lightning, and precipitation limits based on scientific
knowledge, engineering judgment, and experience.

## This Rule Continued on Next Page {#this-rule-continued-on-next-page-2 .Cont}

## A2-6 LANDING SITE WEATHER CRITERIA \[hc\] (continued) {#a2-6-landing-site-weather-criteria-hc-continued-3 .Cont}

The 20 nm and 15 nm radii around the landing site approximate a 10 nm
and 5 nm lateral clearance from all HAC's, respectively. Increasing the
radial and lateral limits for EOM, AOA, PLS, and ELS adds protection for
the uncertainty associated with a longer forecast. The post-commitment
clearances balance the risks associated with a runway redesignation and
damage from flying through precipitation or probability of incurring a
lightning strike. Clearances are lower for detached nontransparent
thunderstorm anvils because the probability for triggered lightning is
lower. An attached anvil is part of the thunderstorm and must meet the
thunderstorm proximity limits if the anvil is nontransparent. At the
January and April 1998 meetings of the Lightning Advisory Panel (LAP),
the consensus was that transparent anvil clouds do not pose a triggered
lightning threat. Evaluation of anvils is sometimes difficult and
inexact, even with modern remote sensing technology. ®\[111298-6734 \]
®\[022604-6167A\]

At the January and April 1998 meetings of the Lightning Advisory Panel,
LAP members stated that applicable research indicated that cumulus
clouds formed by fires and smoke pose a threat of triggered lightning if
penetrated and should be avoided for up to 1 hour after the cloud
detaches from the source fire or smoke. ®\[111298-6734 \]
®\[111094-1622B\] ®\[020196-1808A\] ®\[022604-6167A\]

ACLS/ECAL/ELS LIMITS ®\[111094-1622B\] ®\[020196-1808A\]

Weather at the site must be acceptable to provide good visibility during
final approach, since lateral and longitudinal margins are minimal at
ECAL/ELS sites. As long as visibility and ceiling limits are met, there
is no constraint for precipitation. Additional constraints to avoid
thunderstorms and lightning apply only to the landing site. The
definition for "none at site" used in the Shuttle Program will mean that
no thunderstorm is over the landing airfield. Note that operational
meteorological reporting standards for weather occurring at a site
differs slightly from the definition applied for shuttle landings. For
thunderstorm and lightning observations (METAR) and forecasts (TAF) used
to evaluate the GO/NO-GO status of an ACLS/ECAL/ELS site prior to
launch, meteorological reporting standards define "none at site" as: no
thunderstorms or lightning within 5 statute miles of the observing
(landing) site. ®\[111298-6734 \]

## This Rule Continued on Next Page {#this-rule-continued-on-next-page-3 .Cont}

## A2-6 LANDING SITE WEATHER CRITERIA \[hc\] (continued) {#a2-6-landing-site-weather-criteria-hc-continued-4 .Cont}

RTLS AND TAL PRECIPITATION LIMITS ®\[121604-6533A\]

[Intent:]{.underline} Providing a safe approach at the abort landing
time is of prime importance. However, additional launch probability may
be gained by allowing showers within the precipitation limits specified
in Table A2-6-III that do not pose a threat due to lightning, hail,
visibility, aerodynamic control, or MLS attenuation. The "rainshower
rule" is intended for use with non-hazardous rainshowers that cover a
small fraction of the area surrounding the abort landing site on launch
day. The rainshower allowance criteria are dependent on the
precipitation intensity, the presence of frozen precipitation, and the
potential for triggered lightning. Cumulonimbus clouds (either with or
without observed lightning) are excluded from consideration under this
rule due to the potential for triggered lightning, turbulence, hail, and
heavy rainshowers. Rainshowers over the runway may negatively affect
runway acceptability conditions; Rule {A4-111}, RUNWAY ACCEPTABILITY
CONDITIONS, still applies. Reference A/E FTP: \# 109,111,195, 198, 204.
®\[020196-1808A\]

At A/E FTP #198, SMG discussed the potential application of the
rainshower rule for TAL abort. SMG determined that European weather
satellite and Spanish radar imagery may be adequate to apply the rule at
Zaragoza and Moron, under some meteorological conditions. However, the
current tools are not sufficient to apply the rule at other TAL sites.
It was also noted that the TAL upper air climatology indicates that the
rules utility will be limited during all but the summer months since
cloud top temperatures will be colder than +5 deg C for much of the
year. ®\[021998-6490A\]

[Tools needed for application of the rule (Paragraph A)]{.underline}:
For forecast intervals less than 45 minutes, the availability of radar
surveillance, satellite imagery, and a weather reconnaissance aircraft
may allow improved estimation of rainshower movement, development, and
characterization of the cloud type.  These meteorological tools and the
weather aircraft are critical in determining the
stability/predictability of the showers in order to provide a safe
approach at the abort landing time.  Degradation or lack of any one of
these tools may be sufficient to avoid using this rule on a given launch
day.  In general, the minimum requirements to evaluate the light
rainshowers include availability of the following:

Visible or infrared satellite imagery every 15 minutes.

A ground based weather radar producing a composite reflectivity product
(maximum reflectivity in a column above a point on the ground) that
completes a full volume scan at least every 10 minutes.

A weather aircraft capable of flying near the showers of interest such
that the NASA Weather Recon astronaut can evaluate the weather
conditions including cloud height, thickness, and location;
precipitation, virga, or moisture on the windscreen; and slant range
visibility of the runway environment, papis, and ball-bar.
®\[121604-6533A\]

## This Rule Continued on Next Page {#this-rule-continued-on-next-page-4 .Cont}

## A2-6 LANDING SITE WEATHER CRITERIA \[HC\] (continued) {#a2-6-landing-site-weather-criteria-hc-continued-5 .Cont}

[Potential for Development (Paragraph B):]{.underline} Predicting the
development of new areas of convection is the challenge in applying the
rainshower rule. It is not likely that extrapolation of showers based on
their motion at the launch decision time will accurately predict the
locations of showers at the abort landing time. Rather, the conditions
at the launch decision should be representative of those conditions
expected at the abort landing time. The potential for development should
be limited: the character of the clouds and showers should be expected
to change little from the observed conditions throughout the forecast
period and neither the total cloud cover nor the maximum intensity of
the showers should be expected to increase. ®\[020296-1808A\]
®\[121604-6533A\]

[Movement (Paragraph C)]{.underline} - Consistent horizontal motion that
is linear or near linear and can be tracked is required to accurately
forecast future movement and to ensure the synoptic situation is
relatively predictable. However, it should be noted that 20-40 minutes
is considered the practical limit for extrapolating weather features
such as small lines of weak showers. The life cycle for a typical
rainshower is about 30 minutes. This rule is being applied near the
limits of predictability for these features. The extrapolation of larger
features that may cause the development of new showers, such as the sea
breeze, is valid over longer periods of time. The size of the phenomena
and the limitations of extrapolation need to be considered when applying
this rule. ®\[020196-1808A\]

[Runway Acceptability Conditions (Paragraph D)]{.underline} - Allowing
rainshowers within 20 nm of the center of the runway increases the
chances of rain occurring on the runway. The runway conditions shall be
observed "GO" at the launch decision time. In addition, the runway
conditions shall be forecast to remain "GO" after considering the
potential accumulation of rainfall on the surface due to the
rainshowers.

[Requirement for Two Approaches (Paragraph E)]{.underline}- Removing the
requirement for acceptable weather for all four approaches increases
launch availability. The requirement for acceptable weather for two
approaches maintains the capability for an energy down mode option. To
satisfy this requirement for a 39-degree inclination launch, both an
overhead and a straight-in approach must be "GO". ®\[121604-6533A\]

## This Rule Continued on Next Page {#this-rule-continued-on-next-page-5 .Cont}

## A2-6 LANDING SITE WEATHER CRITERIA \[HC\] (continued) {#a2-6-landing-site-weather-criteria-hc-continued-6 .Cont}

[Precipitation Considerations and Avoidance (Paragraph
E.1):]{.underline} ®\[121604-6533A\]

In 1994, the Shuttle Program stated that the tile damage that occurs if
light precipitation is encountered is acceptable. The orbiter would
encounter the light rainshowers at altitudes below about 15,000 feet
during approach and landing based on typical upper air temperatures at
the landing sites. While flight through light precipitation was deemed
acceptable, the AEFTP stated rainshower avoidance is still more
desirable, if possible. In 2004, AEFTP 204 determined that the orbiter
should not be allowed to fly through rainshowers until issues raised at
the panel meeting are addressed. These issues include the effects of
downdraft winds and wet runway considerations. Therefore, the orbiter
shall not fly through any precipitation.

Limiting the application of this rule to rainshowers (stratocumulus and
cumulus cloud types) minimizes the total area covered by rain (compared
to stratiform clouds) and the likelihood of undesirable weather
conditions associated with those showers such as turbulence and
downdrafts. Moderate or greater precipitation is to be avoided by
adequate distances in order to avoid damage to the thermal protection
system and increased likelihood of turbulence, downdraft winds, and
visibility reduction.

A retrim to a slightly higher angle of attack would be the primary
noticeable response to flight through rain during landing approach.
Light precipitation will not damage the structure or control system.
Testing indicates that damage to RCC does not occur when flown through
light rain at speeds below 0.7 Mach. RCC damage is not desirable due to
replacement cost and lead-time. RCC damage caused by precipitation
impact would not affect aerodynamic performance. ®\[020296-1808A\]

Testing of TPS tiles flown through rainfall of 35 to 40 dBZ indicates
that significant tile damage will occur if the orbiter encounters
ice-free precipitation at velocities below Mach 1 and above touchdown
speed. The extent of damage depends on drop size and the angle of
incidence between a drop and a tile. Estimates of effects on approach
and landing characteristics assuming an estimate of approximately 2000
damaged tiles (nose and canopy/windshield areas, vertical tail and OMS
pod leading edges) presented at AEFTP #204 show a loss of up to 1750 ft
of touchdown distance (approx 1400 ft due to tile damage, approx 350 ft
due to momentum loss to the rain and cloud). The estimate of the
touchdown distance loss is based on an increased drag increment of 65
counts for tile damage, 3 counts for momentum loss while flying in rain
drops, and 20 counts for momentum loss while flying in cloud drops. As
specified in Rule {A4-110}, AIMPOINT, SPEEDBRAKE RETRACT OPTION, AND
EVALUATION TOUCHDOWN VELOCITY SELECTION \[HC\], prelaunch touchdown
predictions account for the increased drag increment due to flying
through light rain. Consideration should be given to not launching on a
low energy day where the capability to avoid showers is low.
®\[020196-180\] ®\[121604-6533A\]

## This Rule Continued on Next Page {#this-rule-continued-on-next-page-6 .Cont}

## A2-6 LANDING SITE WEATHER CRITERIA \[HC\] (continued) {#a2-6-landing-site-weather-criteria-hc-continued-7 .Cont}

If the orbiter encounters ice, window damage may occur resulting in
reduced visibility (depending on ice population, mass, density, and
relative velocity) and RCC coating damage may occur forcing RCC panel
replacement. Clouds with tops warmer than +5 deg C thermal layer are
warm enough to assure they do not contain hail. Clouds with tops colder
than +5 deg C are to be avoided by an adequate distance.
®\[121604-6533A\]

Water attenuates microwave signals at MLS frequencies; however, MLS
performance is not severely affected. Analysis of MLS link performance
with a transmitter power output of 1600 W (the minimum acceptable
transmitter power output level) shows that MLS acquires at over 9 nm
slant range when a rainfall rate of 10 mm/hr (0.4 in/hr) exists along
the entire path between the orbiter and the ground MLS station. Since
"light" rainfall is less than 0.4 in/hr, nominal MLS acquisition is
protected.

[Cloud Top Temperatures and Lightning Avoidance (Paragraph
E.2):]{.underline} Clouds with tops warmer than +5 deg C do not pose a
threat of stored electrical charge. Clouds with tops colder than +5 deg
C pose a threat of lightning (natural and triggered). Convective clouds
that have previously been colder than -10 deg C have probably generated
electric charge; these clouds must be avoided for 3 hours to allow the
charge to dissipate (See Lightning Launch Commit Criteria for surface
based electric field mills). The 3-hour time limit is calculated
relative to the abort landing time (approximately 2 1/2 hours prior to
launch). A 2-nm vertical clearance or a 10-nm lateral clearance must be
maintained along the approach path for showers exceeding these limits.
The clearance requirements for lightning potential are the same as those
of actual thunderstorms. These criteria are consistent with the
Lightning Advisory Panel's recommended Lightning Launch Commit Criteria.
®\[021998-6490A\]

[Relationship to Ceiling and Visibility Limit Criteria:]{.underline}
Ceiling and visibility criteria specified in paragraph A of this rule
still apply and protect for adequate crew visibility of the PAPI's,
aimpoint, and ball bar through clouds and precipitation. WX RECON has
primary responsibility for assessing visibility through light
precipitation from any showers of concern that do not fall within the
field of view used by meteorological observers to evaluate visibility.
Ground observers are limited to evaluations using fixed landmarks.
®\[121604-6533A\]

Rules {A2-1F}, PRELAUNCH GO/NO-GO REQUIREMENTS; {A2-2}, ABORT LANDING
SITE REQUIREMENTS; {A2-103}, EXTENSION DAY REQUIREMENTS; {A2-202},
EXTENSION DAY GUIDELINES; {A2-205}, EMERGENCY DEORBIT; {A2-261}, ENTRY
DTO/AUTO MODE/CROSSWIND DTO GO/NO-GO; {A3-202}, MLS; {A4-107}, PLS/EOM
LANDING OPPORTUNITY REQUIREMENTS \[HC\]; {A5-103}, LIMIT SHUTDOWN
CONTROL; {A8-18}, LANDING SYSTEMS REQUIREMENTS; and {A8-1001}, GNC
GO/NO-GO CRITERIA, reference this rule. ®\[111094-1622B\]
®\[020196-1808A\] ®\[ED          \]

## This Rule Continued on Next Page {#this-rule-continued-on-next-page-7 .Cont}

##  {#section .Cont}

**THIS PAGE INTENTIONALLY BLANK**

**note to flight rules team:**

> **this page sets off the tables on the next page providing a "pull-out
> page" for mcc use.**

## A2-6 LANDING SITE WEATHER CRITERIA \[HC\] (continued) {#a2-6-landing-site-weather-criteria-hc-continued-8 .Cont}

+----------------------+--------+-----+------------+---+--------+-------+
| CEILING / VISIBILITY |        |     | REDUNDANT  | S |        | NO    |
|                      |        |     |            | I |        | MLS   |
| (K FT)/(SM)          |        |     | MLS        | N |        |       |
|                      |        |     |            | G |        |       |
|                      |        |     |            | L |        |       |
|                      |        |     |            | E |        |       |
|                      |        |     |            | S |        |       |
|                      |        |     |            | T |        |       |
|                      |        |     |            | R |        |       |
|                      |        |     |            | I |        |       |
|                      |        |     |            | N |        |       |
|                      |        |     |            | G |        |       |
|                      |        |     |            | - |        |       |
|                      |        |     |            | M |        |       |
|                      |        |     |            | L |        |       |
|                      |        |     |            | S |        |       |
+----------------------+--------+-----+------------+---+--------+-------+
| KSC, EDW, NOR,       | CO     | DAY |            | ≥ |        |       |
|                      | NCRETE |     |            | 1 |        |       |
|                      |        |     |            | 0 |        |       |
|                      |        |     |            | / |        |       |
|                      |        |     |            | 7 |        |       |
+----------------------+--------+-----+------------+---+--------+-------+
| AOA,                 |        | NI  | ≥8/5       | N |        |       |
|                      |        | GHT |            | O |        |       |
|                      |        |     |            | - |        |       |
|                      |        |     |            | G |        |       |
|                      |        |     |            | O |        |       |
+----------------------+--------+-----+------------+---+--------+-------+
| DAILY PLS SELECTION  | L      | DAY | (WX RECON  |   |        | ≥10/7 |
| (ALL SITES)          | AKEBED |     | REQD)      |   |        |       |
+----------------------+--------+-----+------------+---+--------+-------+
|                      |        | NI  |            | ≥ |        | nO go |
|                      |        | GHT |            | 1 |        |       |
|                      |        |     |            | 5 |        |       |
|                      |        |     |            | / |        |       |
|                      |        |     |            | 7 |        |       |
+----------------------+--------+-----+------------+---+--------+-------+
| RTLS, TAL            | CO     | DAY | ≥5/4 RTLS  | ≥ |        |       |
|                      | NCRETe |     |            | 1 |        |       |
|                      |        |     | ≥5/5 TAL   | 0 |        |       |
|                      |        |     |            | / |        |       |
|                      |        |     |            | 7 |        |       |
+----------------------+--------+-----+------------+---+--------+-------+
|                      |        | NI  | (WX RECON  | N |        |       |
|                      |        | GHT | REQD)      | O |        |       |
|                      |        |     |            | G |        |       |
|                      |        |     |            | O |        |       |
+----------------------+--------+-----+------------+---+--------+-------+
| ACLS / ECAL / ELS    |        |     | 0/0        |   |        | ≥8/5  |
+----------------------+--------+-----+------------+---+--------+-------+
| PRED/o: 1 APU FAILED |        |     |            |   | ≥10/7  |       |
| OR ATTEMPT 2 APU's   |        |     |            |   |        |       |
| PROCEDURE            |        |     |            |   |        |       |
+----------------------+--------+-----+------------+---+--------+-------+

®\[022604-6167A\]

+------+---------------+---+------+------+------+------+------+-------+
| *    |               |   | *    | **HE | **TA | **TA | **GU | **T   |
| *SUR |               |   | *CRO | AD** | IL** | IL** | ST** | URB** |
| FACE |               |   | SS** |      |      |      |      |       |
| WIND |               |   |      | **PE | **A  | **PE |      |       |
| (    |               |   | **pE | AK** | VG** | AK** |      |       |
| KNOT |               |   | AK** |      |      |      |      |       |
| S)** |               |   |      |      |      |      |      |       |
|      |               |   |      |      |      |      |      |       |
| *    |               |   |      |      |      |      |      |       |
| *AND |               |   |      |      |      |      |      |       |
| TURB |               |   |      |      |      |      |      |       |
| ULEN |               |   |      |      |      |      |      |       |
| CE** |               |   |      |      |      |      |      |       |
+------+---------------+---+------+------+------+------+------+-------+
| RTLS |               |   | ≤15  | ≤25  | ≤10  | ≤15  | [\   | [\<]  |
|      |               |   | \*   |      |      |      | <]{. | {.und |
|      |               |   |      |      |      |      | unde | erlin |
|      |               |   |      |      |      |      | rlin | e}MOD |
|      |               |   |      |      |      |      | e}10 |       |
+------+---------------+---+------+------+------+------+------+-------+
| DAY  | EOM, TAL,     |   | ≤15  |      |      |      |      |       |
|      | AOA,          |   |      |      |      |      |      |       |
|      |               |   |      |      |      |      |      |       |
|      | DAILY PLS     |   |      |      |      |      |      |       |
|      | SELECTION     |   |      |      |      |      |      |       |
+------+---------------+---+------+------+------+------+------+-------+
| N    | EOM           |   | ≤12  |      |      |      |      |       |
| IGHT |               |   |      |      |      |      |      |       |
|      | DAILY PLS     |   |      |      |      |      |      |       |
|      | SELECTION     |   |      |      |      |      |      |       |
+------+---------------+---+------+------+------+------+------+-------+
|      | TAL, AOA      |   | ≤15  |      |      |      |      |       |
+------+---------------+---+------+------+------+------+------+-------+
| C    |               |   | ≥10  |      |      |      |      |       |
| ROSS |               |   |      |      |      |      |      |       |
| WIND |               |   | ≤15  |      |      |      |      |       |
| DTO  |               |   |      |      |      |      |      |       |
+------+---------------+---+------+------+------+------+------+-------+
| NOM  |               |   | ≤15  |      |      |      |      |       |
| INAL |               |   |      |      |      |      |      |       |
| DRAG |               |   |      |      |      |      |      |       |
| C    |               |   |      |      |      |      |      |       |
| HUTE |               |   |      |      |      |      |      |       |
| DE   |               |   |      |      |      |      |      |       |
| PLOY |               |   |      |      |      |      |      |       |
+------+---------------+---+------+------+------+------+------+-------+
| LAN  |               |   | ≤12  |      |      |      |      |       |
| DING |               |   |      |      |      |      |      |       |
| ≥    |               |   |      |      |      |      |      |       |
| CDR  |               |   |      |      |      |      |      |       |
| FD19 |               |   |      |      |      |      |      |       |
+------+---------------+---+------+------+------+------+------+-------+
| PRE  |               |   | ≤10  |      |      |      |      | ≤LGT  |
| DEOR |               |   |      |      |      |      |      |       |
| BIT: |               |   |      |      |      |      |      |       |
| 1    |               |   |      |      |      |      |      |       |
| APU  |               |   |      |      |      |      |      |       |
| FA   |               |   |      |      |      |      |      |       |
| ILED |               |   |      |      |      |      |      |       |
| OR   |               |   |      |      |      |      |      |       |
| ATT  |               |   |      |      |      |      |      |       |
| EMPT |               |   |      |      |      |      |      |       |
| 2    |               |   |      |      |      |      |      |       |
| A    |               |   |      |      |      |      |      |       |
| PU's |               |   |      |      |      |      |      |       |
| P    |               |   |      |      |      |      |      |       |
| ROCE |               |   |      |      |      |      |      |       |
| DURE |               |   |      |      |      |      |      |       |
+------+---------------+---+------+------+------+------+------+-------+
| ECAL |               |   | ≤15  |      |      | N/A  |      |       |
| /ELS |               |   |      |      |      |      |      |       |
+------+---------------+---+------+------+------+------+------+-------+

®\[121400-3866 \] ®\[052401-4459A\]

+-----------------+---------------+---------+---------+-------+-------+
| **THUNDERSTORM, |               | **PREL  | **PREDE | *     | **E   |
| LIGHTNING, AND  |               | AUNCH** | ORBIT** | *REDE | LS,** |
| PRECIPITATION   |               |         |         | SIG** |       |
| PROXIMITY       |               | *       | **      |       | **EC  |
| LIMITS (NM)**   |               | *(RTLS, | (EOM,** | **    | AL,** |
|                 |               | TAL)**  |         | CRITE |       |
|                 |               |         | **DAILY | RIA** | **A   |
|                 |               |         | PLS)**  |       | CLS** |
|                 |               |         |         |       |       |
|                 |               |         | **PR    |       |       |
|                 |               |         | ELAUNCH |       |       |
|                 |               |         | (AOA)** |       |       |
+=================+===============+=========+=========+=======+=======+
|                 | RADIAL FROM   | \>20    | \>30    | \>15  |       |
|                 | CENTER OF     |         |         |       |       |
|                 | PRIME RUNWAY  |         |         |       |       |
+-----------------+---------------+---------+---------+-------+-------+
| TSTORM (includ  | LATERAL ALONG | \>10    | \>20    | \>5   | NONE  |
| attACH          | APPROACH PATH |         |         |       | AT    |
| nontrans-parent | OUT TO 30 NM  |         |         |       | SITE  |
| anvils), &      |               |         |         |       |       |
| LIGHTNING       |               |         |         |       |       |
+-----------------+---------------+---------+---------+-------+-------+
|                 | VERTICAL FROM | \>2     |         |       |       |
|                 | TOP OF CLOUD  |         |         |       |       |
+-----------------+---------------+---------+---------+-------+-------+
|                 | RADIAL FROM   | \>15    | \>20    | \>15  | N/A   |
|                 | CENTER OF     |         |         |       |       |
|                 | PRIME RUNWAY  |         |         |       |       |
+-----------------+---------------+---------+---------+-------+-------+
| DETACHED        | LATL ALONG    | \>5     | \>10    | \>5   |       |
| nontrnsparnt    | APPROACH PATH |         |         |       |       |
| ANVIL \< 3 HRS  | OUT TO 30 NM  |         |         |       |       |
| OLD             |               |         |         |       |       |
+-----------------+---------------+---------+---------+-------+-------+
|                 | VERTICAL FROM | \>2     |         |       |       |
|                 | TOP OF CLOUD  |         |         |       |       |
+-----------------+---------------+---------+---------+-------+-------+
|                 | RADIAL FROM   | \>20    | \>30    | \> 15 | N/A   |
|                 | CENTER OF     |         |         |       |       |
|                 | PRIME RUNWAY  |         |         |       |       |
+-----------------+---------------+---------+---------+-------+-------+
| pRECIPITATION   | LATL ALNG     | \>10    | \>20    | \> 5  |       |
| \*              | APPRCH PATH   |         |         |       |       |
|                 | OUT TO 30 NM  |         |         |       |       |
+-----------------+---------------+---------+---------+-------+-------+
|                 | VERT FRM TOP  | \>2     |         |       |       |
|                 | OF CLD        |         |         |       |       |
+-----------------+---------------+---------+---------+-------+-------+
| Cmlus clds prod | Lateral along | \>0     |         |       | N/A   |
| by s/f ≤ 1 hr   | approach path |         |         |       |       |
| aftr detaching  |               |         |         |       |       |
+-----------------+---------------+---------+---------+-------+-------+

## This Rule Continued on Next Page  {#this-rule-continued-on-next-page-8 .Cont}

##  {#section-1 .Cont}

**THIS PAGE INTENTIONALLY BLANK**

**note to flight rules team:**

> **this page sets off the tables on the previous page providing a
> "pull-out page" for mcc use.**

## A2-6 LANDING SITE WEATHER CRITERIA \[HC\] (CONTINUED) {#a2-6-landing-site-weather-criteria-hc-continued-9 .Cont}

D. Flight Rule Weather Definitions ®\[081497-6278A\] ®\[022604-6167A\]

The following definitions are used when evaluating the weather flight
rules:

CLOUDS

[Ceiling]{.underline} - The height above ground where the cumulative
total of cloud cover exceeds 50 percent coverage of sky. The height
above the earth's surface of the lowest layer reported as broken or
overcast, or the vertical visibility into a surface based obscuration
reported as a ceiling.

[Cloud edge]{.underline} - The visible edge shall be used whenever
possible. If this is not possible, meteorological judgment of available
radar and other data shall be used to determine the cloud edge. The
maximum radar reflectivity that can be considered to represent the cloud
edge is 0 dBZ, although a lower value may be representative on any
particular day.

[Cloud top]{.underline} - The height of cloud using the visibly
determined top. If this is not possible, meteorological judgment of
available radar, satellite, and other measurements shall be used to
determine the cloud top. The maximum radar reflectivity that can be
considered to represent the top is 0 dBZ, although a lower value may be
representative on any particular day.

[Debris Cloud]{.underline} - Any cloud, except anvil cloud, that has
become detached from a parent cumulonimbus or thunderstorm, or that
results from the decay of a parent cumulonimbus cloud or thunderstorm.
For the purposes of Flight Rule evaluation, debris clouds are considered
in the same category as detached anvil clouds.

[Nontransparent]{.underline} - Sky cover through which forms are
blurred, indistinct, or obscured is nontransparent. It is the opposite
of transparent. Sky cover through which forms are seen and identified
through breaks in the cloud shall be considered as nontransparent.
Clouds with radar reflectivity of 0 dBZ or greater shall be considered
nontransparent. ®\[ED          \]

[Transparent]{.underline} - Sky cover shall be considered transparent
when higher clouds, blue sky, or stars may be seen and identified from
below or when terrain, buildings or landmarks may be seen and identified
from above. ®\[022604-6167A\]

## THIS RULE CONTINUED ON NEXT PAGE {#this-rule-continued-on-next-page-9 .Cont}

## A2-6 LANDING SITE WEATHER CRITERIA \[HC\] (CONTINUED) {#a2-6-landing-site-weather-criteria-hc-continued-10 .Cont}

CLOUD COVERAGE ®\[081497-6278A\] ®\[022604-6167A\]

[Clear (SKC)]{.underline} - No clouds or obscurations observed or
detected

[Few]{.underline} - Total layer sky coverage of 2/8 or less

[Scattered (SCT)]{.underline} - Total layer sky coverage of 3/8 to 4/8

[Broken (BKN)]{.underline} - Total layer sky coverage of 5/8 to 7/8

[Overcast (OVC)]{.underline} - Total layer sky coverage of 8/8

OBSERVATIONS

[METAR (Surface Meterological Airways)]{.underline} - Routine
meteorological report using an international coding standard developed
by the World Meteorological Organization

[None at site]{.underline} - For Flight Rules purposes, none at site
shall mean that the designated phenomenon is not directly over the
landing airfield. ®\[022604-6167A\]

## THIS RULE CONTINUED ON NEXT PAGE  {#this-rule-continued-on-next-page-10 .Cont}

## A2-6 LANDING SITE WEATHER CRITERIA \[hc\] (CONTINUED) {#a2-6-landing-site-weather-criteria-hc-continued-11 .Cont}

Precipitation ®\[081497-6278A\] ®\[022604-6167A\]

Precipitation is defined as any of the forms of water particles, liquid
or solid, which fall from the atmosphere and reach the ground. Rain
droplets observed on the windscreen of weather aircraft, radar
reflectivity of 18 dBZ or greater, cumulonimbus clouds, a radar bright
band, virga, and visible rain or drizzle shall be considered
precipitation for Flight Rules purposes.

[Heavy precipitation]{.underline} - Radar reflectivity values greater
than or equal to 38 dBZ or rainfall rate greater than 0.30 inches/hr

[Light precipitation]{.underline} - Radar reflectivity values greater
than or equal to 18 dBZ and less than 30 dBZ, or a rainfall rate of 0.10
inches/hr or less

[Moderate precipitation]{.underline} - Radar reflectivity values greater
than or equal to 30 dBZ and less than 38 dBZ, or a rainfall rate of 0.11
to 0.30 inches/hr

[Radar bright band]{.underline} - Area of enhanced radar reflectivity
produced by frozen precipitation falling through the 0 degrees C level
and melting

[Virga]{.underline} - Visible wisps or strands or precipitation falling
from clouds that evaporate before reaching the ground ®\[022604-6167A\]

## THIS RULE CONTINUED ON NEXT PAGE  {#this-rule-continued-on-next-page-11 .Cont}

## A2-6 LANDING SITE WEATHER CRITERIA \[hc\] (CONTINUED) {#a2-6-landing-site-weather-criteria-hc-continued-12 .Cont}

Thunderstorm ®\[081497-6278A\] ®\[022604-6167A\]

Any cloud producing lightning or one that has produced lightning within
the past 15 minutes. Cumulonimbus clouds and the nontransparent portion
of attached anvils shall be considered as part of a thunderstorm for
Flight Rules evaluation.

[Anvil]{.underline} - The flat, fibrous, spreading top of a thunderstorm
or cumulonimbus cloud. Stratiform or fibrous ice crystal cloud produced
by the upper level outflow or blow-off from thunderstorms or convective
clouds. For Flight Rules purposes, an attached anvil shall be considered
as part of the thunderstorm.

[Cumulonimbus]{.underline} - A dense and vertically developed cloud that
appears as huge towers, usually with an upper part that is smooth,
fibrous, striated, or almost flattened. Any convective cloud with any
part colder than -20 degrees C shall be considered a cumulonimbus cloud
and treated like a thunderstorm for Flight Rules purposes.

[Detached anvil]{.underline} - An anvil cloud that becomes physically
separated from the parent thunderstorm or cumulonimbus cloud. Any cloud
resulting from the decay of a thunderstorm or cumulonimbus cloud shall
be considered as a detached anvil for Flight Rule purposes.

Triggered lightning

Lightning that is initiated by placing an object such as a rocket or
airplane into an electric field

Turbulence

[Light]{.underline} - Turbulence that momentarily causes slight, erratic
changes in altitude and/or attitude

[Moderate]{.underline} - Turbulence that causes changes in altitude
and/or attitude, but with the aircraft remaining in positive control

[Severe]{.underline} - Turbulence that causes large, abrupt changes in
altitude and/or attitude. It usually causes large variations in
indicated airspeed. Aircraft may momentarily be out of control.

[Extreme]{.underline} - Turbulence in which the aircraft is violently
tossed about and is practically impossible to control. It may cause
structural damage. ®\[022604-6167A\]

## THIS RULE CONTINUED ON NEXT PAGE  {#this-rule-continued-on-next-page-12 .Cont}

## A2-6 LANDING SITE WEATHER CRITERIA \[HC\] (CONTINUED) {#a2-6-landing-site-weather-criteria-hc-continued-13 .Cont}

WIND ®\[081497-6278A\] ®\[022604-6167A\]

The forecast wind is a 2-minute average and 10-minute peak at the
expected landing time. The observed wind will be the average and peak
available from the landing site which may be a 1, 2, or 5 minute average
and a 5, 10, or 15 minute peak depending on the site.

[Average wind]{.underline} - Wind direction or speed averaged over a
period of time. Typically, at landing sites in the continental U.S., a
2-minute average of 1-second measurements is used.

[Crosswind]{.underline} - The crosswind is the component of the wind
perpendicular to the runway or vehicle flight path.

[Gust]{.underline} - For Flight Rules purposes, a gust shall be defined
as the difference between the average and peak winds over a specified
duration, usually 10 minutes.

[Headwind]{.underline} - The headwind is the component of the wind
parallel to the runway or vehicle flight path that opposes the intended
progress of the vehicle. It is in the opposite direction of the
tailwind.

[Peak wind]{.underline} - The direction and speed of the maximum
instantaneous wind over a specified duration, usually 10 minutes.

[Tailwind]{.underline} - The tailwind is the component of the wind
parallel to the runway or vehicle flight path that assists in the
intended progress of the vehicle. It is in the opposite direction of the
headwind.

VISIBILITY

[Restrictions to visibility]{.underline} - Any phenomenon that reduces
horizontal or slant range visibility such as smoke, haze, fog, dust,
clouds, and precipitation.

[Vertical visibility]{.underline} - A subjective or instrumental
evaluation of the vertical distance into a surface based obscuration
that an observer would be able to see. ®\[022604-6167A\]

##