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Appendix D
Proposed Weather Factors Governing
Launch Commit Criteria and Flight Rules
62
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63
Shuttle Launch Commit Criteria and Background
JSC-16007
Sec. 1.4
Weather Guidelines/Rules
LCC RULE: AMBIENT TEMPERATURE RESTRICTIONS
A. PRIOR TO EXTERNAL TANK CRYOGENIC LOADING.
PROPELLANT LOADING OF THE EXTERNAL TANK (ET) SHALL NOT BE
INITIATED IF THE 24 HOUR AVERAGE TEMPERATURE FOR THE PRECEEDING 24
HOURS HAS BEEN BELOW 41 DEGREES FAHRENHEIT.
B. FROM START OF ET CRYOGENIC LOADING TO LAUNCH.
THE COUNTDOWN SHALL NOT BE CONTINUED NOR THE SHUTTLE LAUNCHED IF
THE AMBIENT TEMPERATURE DURING THIS TIME PERIOD EXCEEDS ANY OF THE
FOLLOWING CRITERIA FOR MORE THAN 30 MINUTES.
(1) MAXIMUM TEMPERATURE OF 99 DEGREES FAHRENHEIT
(2) MINIMUM TEMPERATURE OF 37 DEGREES FAHRENHEIT FOR WIND
CONDITIONS AT OR ABOVE 5 KNOTS.
(3) MINIMUM TEMPERATURE OF 47 DEGREES FAHRENHEIT FOR STEADY STATE
WIND CONDITIONS BELOW 5 KNOTS.
LCC RULE: PRECIPITATION CONSTRAINT
THE SHUTTLE VEHICLE WILL NOT BE LAUNCHED IF:
A. PRECIPITATION EXISTS IN THE FLIGHT PATH
B. ICE ACCUMULATES IN ZERO-ICE OR RESTRICTED THICKNESS AREAS ON THE
ET.
Rationale: Thermal Tile Protection
LCC RULE: SURFACE WIND LIMITS FOR LIFT-OFF (MEASURED AT 60' LEVEL)
THE SHUTTLE VEHICLE WILL NOT BE LAUNCHED IF:
WINDS ARE GREATER THAN:
A. 22 KNOTS - STEADY STATE
PRELIMINARY
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64
B. 32 KNOTS - PEAK
Rationale: Design Requirement of JSC 07700 Vol X
LCC RULE: NATURAL AND TRIGGERED LIGHTNING CONSTRAINTS
THE LAUNCH WEATHER OFFICER MUST HAVE CLEAR AND CONVINCING EVIDENCE THAT
THE FOLLOWING CONSTRAINTS ARE NOT VIOLATED.
DO NOT LAUNCH IF:
A. ANY TYPE OF LIGHTNING IS DETECTED WITHIN 10 NM OF THE LAUNCH SITE
OR PLANNED FLIGHT PATH WITHIN 30 MINUTES PRIOR TO LAUNCH UNLESS
THE METEOROLOGICAL CONDITION THAT PRODUCED THE LIGHTNING HAS MOVED
MORE THAN 10 NM AWAY FROM THE LAUNCH SITE OR PLANNED FLIGHT PATH.
PLANNED FLIGHT PATH: THE TRAJECTORY OF THE FLIGHT VEHICLE FROM
THE LAUNCH PAD THROUGH ITS FLIGHT PROFILE UNTIL IT REACHES THE
ALTITUDE OF 100,000 FEET. THE FLIGHT PATH MAY VARY PLUS OR MINUS
0.5 NAUTICAL MILES HORIZONTALLY UP TO AN ALTITUDE OF 25,000 FEET.
DO NOT LAUNCH IF:
B. THE PLANNED FLIGHT PATH WILL CARRY THE VEHICLE
(1) THROUGH CUMULUS CLOUDS WITH TOPS HIGHER THAN THE +5 C LEVEL;
OR
THROUGH OR WITHIN 5 NM OF CUMULUS CLOUDS WITH TOPS HIGHER
THAN THE -10 LEVEL; OR
THROUGH OR WITHIN 10 NM OF CUMULUS CLOUDS WITH TOPS HIGHER
THAN THE -20 C LEVEL; OR
THROUGH OR WITHIN 10 NM OF THE NEAREST EDGE OF ANY
CUMULONIMBUS OR THUNDERSTORM CLOUD INCLUDING ITS ASSOCIATED
ANVIL
CUMULONIMBUS CLOUD: ANY CONVECTIVE CLOUD WHICH EXCEEDS THE -20 DEGREE
CELSIUS TEMPERATURE LEVEL
ANVIL: STRATIFORM OR FIBROUS CLOUD PRODUCED BY THE UPPER LEVEL OUTFLOW
FROM THE THUNDERSTORMS OR CONVECTIVE CLOUDS. ANVIL DEBRIS DOES
NOT MEET THE DEFINITION IF IT IS OPTICALLY TRANSPARENT
DO NOT LAUNCH IF:
FOR RANGES EQUIPPED WITH A SURFACE ELECTRIC FIELD MILL NETWORK, AT
ANY TIME DURING THE 15 MINUTES PRIOR TO LAUNCH TIME THE ONE MINUTE
AVERAGE ABSOLUTE ELECTRIC FIELD INTENSITY AT THE GROUND EXCEEDS 1
KILOVOLT PER METER (1 KY/M) WITHIN 5 NM OF THE LAUNCH SITE UNLESS:
(A) THERE ARE NO CLOUDS WITHIN 10 NM OF THE LAUNCH SITE: AND,
PRO
Y. l
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65
(B) SMOKE AND/OR GROUND FOG IS CLEARLY CAUSING ABNORMAL READINGS
DO NOT LAUNCH I F:
THE PLANNED FLIGHT PATH IS THROUGH A VERTICALLY CONTINUOUS LAYER
OF CLOUDS WITH AN OVERALL DEPTH OF 4,500 FEET OR GREATER WHERE ANY
PART OF THE CLOUDS ARE LOCATED BETWEEN THE ZERO (O) DEGREE AND THE
MINUS 20 (-20) DEGREE CELSIUS TEMPERATURE LEVELS.
E. THE PLANNED FLIGHT PATH IS THROUGH ANY CLOUD TYPES THAT EXTEND TO
ALTITUDES AT OR ABOVE THE ZERO DEGREE CELSIUS LEVEL AND THAT ARE
ASSOCIATED WITH DISTURBED WEATHER WITHIN 5 NM OF THE FLIGHT PATH
DISTURBED WEATHER: ANY METEOROLOGICAL PHENOMENON THAT IS
PRODUCING MODERATE OR GREATER PRECIPITATION
F. DO NOT LAUNCH THROUGH THUNDERSTORM DEBRIS CLOUDS, OR WITHIN 5 NM
OF THUNDERSTORM DEBRIS CLOUDS NOT MONITORED BY A FIELD MILL
NETWORK OR PRODUCING RADAR RETURNS GREATER THAN OR EQUAL TO 10
DBZ.
DEBRIS CLOUD: IS ANY CLOUD LAYER OTHER THAN A THIN FIBROUS LAYER
THAT HAS BECOME DETACHED FROM THE PARENT
CUMULONIMBUS WITHIN 3 HOURS BEFORE LAUNCH.
Rationale: Based on the known cloud types and conditions which produce
natural and/or triggered lightning
LCC RULE: GOOD SENSE RULE
EVEN WHEN CONSTRAINTS ARE NOT VIOLATED, IF ANY OTHER HAZARDOUS
CONDITIONS EXIST, THE LAUNCH WEATHER OFFICER WILL REPORT THE THREAT TO
THE LAUNCH DIRECTOR. THE LAUNCH DIRECTOR MAY HOLD AT ANY TIME BASED
ON THE INSTABILITY OF THE WEATHER.
LCC RULE: SRB RECOVERY AREA
DO NOT LAUNCH I F:
A. SEA STATE EXCEEDS SEA STATE CODE 5
B. VISIBILITY LESS THAN 1.5 NM
MANDATORY RECOVERY FOR ASSESSMENT OF SOLID ROCKET REDESIGN
LCC RULE: RANGE SAFETY WEATHER RESTRICTIONS
A. BLAST FOCUS (BASED ON SIMULATION USING WEATHER BALLOON AND WIND
DATA)
(1) IF MORE THAN 1 FATALITY PER 100,000 - HOLD OR SCRUB
4
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66
(2) VALUES BETWEEN 1 PER 100,000 AND 1 PER 1,000,000 REqUIRE
EVALUATION BY ESMC COMMANDER
B. CEILING AND VISIBILITY {REqUIRED TO AID RADAR ACqUISITIOM)
- MUST HAVE CLEAR LINE OF SIGHT UP TO 4500 FEET
C. LIGHTNING (PROTECTION OF RANGE DESTRUCT SYSTEM) SAME AS NATURAL
AND TRIGGERED LIGHTNING CONSTRAINTS.
PLEL>~#A~
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67
STS OPERATIONAL FLIGHT RULES
ALL FLIGHTS
FINAL
MAY 9, 1988
PREFACE
THIS PUBLICATION OF THE STS OPERATIONAL FLIGHT RULES, ALL FLIGHTS
(dSC-12820) DATED MAY 9, 1988. REPLACES IN ITS ENTIRETY ALL PREVIOUS
VERSIONS. THIS DOCUMENT AND THE FLIGHT SPECIFIC STS OPERATIONAL FLIGHT
RULES ANNEX (USC-18308) ARE INTENDED TO BE USED IN CONJUNCTION WITH ONE
ANOTHER.
JSC-12820
STS OPERATIONAL FLIGHT RULES IS A CONTROLLED DOCUMENT FOR WHICH CHANGES ARE
SUBJECT TO PROCEDURES DELINEATED IN APPENDIX ~ AND IS NOT TO BE REPRODUCED
WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE CHIEF, FLIGHT DIRECTOR OFFICE,
DAB, LYNDON B. JOHNSON SPACE CENTER.
ORGANIZATIONS WITH COMMENTS, QUESTIONS OR SUGGESTIONS CONCERNING THESE
FLIGHT RULES SHOULD DIRECT THEM TO DAB/C. L. GRUBY, FLIGHT DIRECTOR OfFICE,
BUILDING 29, ROOM lOlB, NASA USE, HOUSTON, TEXAS 77058, TELEPHONE
(713) 483-5558 (FTS 525-5558).
APPROVED BY:
~ _~.
G ~'~ ~ ~ :~/~N
RICHARD H. KOHRS
DEPUTY DIRECTOR, NATIONAL
SPACE TRANSPORTATION SYSTEM
PROGRAM
at'. /
l
/~. 1~--~-~: '
TOMMY W. HOLLOWAY /~\ / LEUGENC F. K NZ
CHIEF, FLIGHT DIRECTOR OFFICE ~ ~ DIRE tOR, MISSION OPERATIONS
ROBERT L. CRIMPER !
DEPUTY DIRECTOR, NATIONAL
SPACE TRANSPORTATION SYSTEM
OPERATIONS
/
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Representative terms from entire chapter:
flight rules
68
NASA- JOHNSON SPACE CENTER
FLIGHT RULES
RULE
R
_
4-64 LANDING SITE WEATHER CRITERIA
THE WEATHER ELEMENT LIMITS CONTAINED IN THIS RULE MUST BE SATISFIED
WITH OBSERVATIONS AT THE GO/NO-GO DECISION TIME AND WITH THE FORE-
CAST FOR LANDING TIME (EXCEPT PRELAUNCH EVALUATION OF THE FLIGHT
DAY 1 PLS WILL ONLY BE BASED ON THE FORECAST). THE APPROACHES TO
BOTH THE PRIME AND BACKUP RUNWAYS AT A GIVEN SITE MUST SATISFY THE
CEILING, VISIBILITY, PRECIPITATION, AND THUNDERSTORM PROXIMITY
LIMITS LISTED BELOW. WHENEVER AVAILABLE' A WEATHER RECONNAISSANCE
FLIGHT WILL PROVIDE A LANDING SITE GO/NO-GO RECOMMENDATION.
A. CEILING AND VISIBILITY LIMITS:
VISIBILITY
CEILING (NOT LESS THAN)
(KFT) (SM L
1. EOM, NEXT PLS
RTLS, TAL, AND ADA 10 (8 O) 7 (5 O)
2. ELS (ORBIT AND ENTRY PHASES) 10 (8 O) 5
3. TAL, ACLS, OR ELS (ASCENT
PHASE) FOR MAIN ENGINE LIMITS
MANAGEMENT (REF. RULE 5-TBD)
OR ABORT GAP CLOSURE (REF.
RULE 4-26H.3, PERFORMANCE
BOUNDARIES)
a. TACAN AND MLS OPERATING N/A N/A
b. TACAN OPERATING, NO MLS 10 5
NOTES:
l ~ APPLIES TO RUNWAY WITH MLS (REF. RULE 3-41, NAVAIDS
PRELAUNCH REQUIREMENTS) AND REQUIRES WEATHER
RECONNAISSANCE FLIGHT EVALUATION.
FOR TAL AND ADA WITH MLS: VISIBILITY MAY BE AS LOW
AS 5 SM ONLY IF THE FOLLOWING LANDING AIDS ARE
VISIBLE AND PREDICTED TO REMAIN VISIBLE ON FINAL
APPROACH (WEATHER RECONNAISSANCE FLIGHT EVALUATION):
(a) PAPI's FROM 8K FT TO PREFLARE
(b) BALL BARS FROM PREFLARE TO FINAL APPROACH
_ _
ALL FINAL 5/9/88 I ~ t~lU
69
NASA - JOHNSON SPACE CENTER
FLIG HT RU LES
R RULE
_
4-64 LANDING SITE WEATHER CRITERIA - Continued
(Cons)
A. CEILING AND VISIBILITY LIMITS - Continued
The meteorological limits in this rule must be met with observations at the GO/NO-GO
decision time and with the forecast for the landing time. This restriction is necessary to
ensure weather uiolatiorts observed at the decision time (ground or weather reconnais
sance) would not permit a GO decision. even if the forecast satisfies the limits. Conversely,
if the forecast indicates a violation of the limits at landing time, a NO-GO decision will be
made, independent of the current observations. Since the flight day 1 PLS landing time is
5 to 10 hours after launch, the forecast will only be used for the prelaunch flight day I PLS
evaluation.
The ceiling, risibility, precipitation, and thunderstorm proximity limits must be met for
approaches to 60th the prime and backup runways, at a given site. This requirement
exists because current forecasting capability cannot accurately ensure that a NO-GO
condition to one of the backup runways would not result in a NO -GO condition at the
prime runway by landing time. Surface wind limits are not required to be met at the
backup runways, since the backup runway would only be required if an energy problem
occurred dictating a runway redesignation.
A ceiling is defined as cloud cover >0.5. There are two ceiling limits, one for runways
with MLS and a higher limit for runways without MLS. Using MLS, the crew can main
tain the approach path accurately to a lower altitude before beginning transition to visual
cues (PAPl's, ball-bar, and runway markings). Eight thousand feet is the lowest layer or
ceilingpermitted using MLS. For runways without MLS, the ceiling minimum is
IOKft. Ceiling limits are established to ensure that the crew has sufficient time after
breaking out of the cloud deck to acquire the runway and landing aids during pre-final
and landing.
_ _ TH IS RULE IS CONTINUED ON THE NEXT PAGE
- ALL FINAL ~ | 5/9/88 1 TRAJECTORY, GUIDANCE
MISS ION REV DATE SECTION
~4-54
_ SEEPAGE NO.
70
NASA - JOHNSON SPACE CENTER
FLIG HT RU LES
R RULE
_
4-64 LANDING SITE WEATHER CRITERIA - Continued
(Cons)
A. CEILING AND VISIBILITY LIMITS - Concluded
The surface visibility limits were established to correspond to the ceiling limits. Slant
range visibility down the Orbiter glide slope is not measurable from the ground, nor is
slant range a standard meteorological measurement. Therefore, the surface visibility and
ceiling limits were established to provide acceptable slant range visibility. Restrictions to
surface visibility include stroke, haze, fog, dust, and clouds. The 7 SM surface visibility
limit generally applies for all landing conditions, with a couple exceptions. The 7 SM is
the horizontal distance component from the runway threshold that correlates to the 10Kft
altitude point on the outer glide slope. For AOA (ED W or NOR) or TAL aborts, the
visibility requirements can be as low as 5 SM if the runway has an MLS and the weather
reconnaissance aircraft verifies that the PAPI's are risible on the approach from 8K fit to
preflare and the ball-bar is visible from preflare to final flare. This lower limit is allowed
at the TAL or lakebed AOA sites where persistent low altitude/surface dust or smoke may
greatly restrict the surface visibility; however, may not pose any significant limitation to
crew "slant range" visibility during final approach to landing. This lower surface
visibility can not be applied to sites which are prone to risibility limitations due to fog or
other transient conditions. The 5 SM limit is the horizontal distance from the runway
threshold that corresponds to the 8K fit altitude point on the outer glide slope. Five SM
visibility is also the minimum limit used is assessing the usability of an ELS.
Specific weather criteria are provided for decisions involving abort gap closure or main
engine limits management during ascent phase. As documented in Rule 5-TBD and its
rationale, in some case following SSME failure, main engine limits will be enabled at the
earliest single-engin~ capability to reach a prime TAL or augmented contingency landing
site (ACLS) (utilizing TAL guidance, event though the site itself may not be a program
recognized TAL site). For this purpose, weather criteria may be relaxed, depending on
landing aids status at the selected site, as a tradeoff to preclude exposure to SSME limits
inhibited operation for any longer than necessary. In this situation, it is considered less
risky to attempt a landing with potentially zero/zero conditions than to continue limits
inhibited SSME operation, provided that both TACAN and MLS are available at the
targeted site. If the site has only an operational TACAN, however, the same ceiling and
visibility restrictions are applied as for orbitlentryphase ELS GO/NO-GO decisions. In
the case of abort gap closure, it is likewise considered reasonable to attempt landing at a
site with relatively poor weather conditions as long as the attempt carries a reasonable
probability of success, when the alternative is an assured ditching situation.
__ _ THIS RULE IS CONTINUED ON THE NEXT PAGE
.
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MISS ION REV DATE SECTION
4-55
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NASA - JOHNSON SPACE CENTER
FLIGHT RULES
R RULE
l
4-64
(Cons)
LANDING SITE WEATHER CRITERIA - Continued
B. SURFACE WIND LIMITS (DAYLIGHT LANDINGS):
1. THE SURFACE WIND LIMITS FOR ALL LANDING SITES ARE AS
FOLLOWS:
a. HEADWIND: s 25 KTS
b. TAILWIND: < 10 KTS
c. CROSSWIND: < 12 KTS
NOTE: SURFACE WIND LIMITS REPRESENT PEAK WINDS, INCLUDING
MAXIMUM GUSTS (GUSTS MUST BE < 8 KTS ABOVE THE
AVERAGE WIND)
2. WITH ONE APU FAILED, SURFACE LIMITS CHANGE AS FOLLOWS:
a. CROSSWIND < 10 KTS
b. NOT GREATER THAN LIGHT TURBULENCE
This table represents the not to be exceeded limits for wind components for the various
landing sites. Head wind limits are established to ensure the Orbiter will land on the run-
way with touchdown margin. Tailwinds affect the landing by causing longer touchdown
ranges, loss of rollout margin, and higher brake energy. Crosswind limits are based upon
Orbiter lateral control and tire wear. The limit of 12 KT peak crosswind corresponds to
the point where the vehicle handling qualities becomes marginal based on Ames VMS
simulations. Gusts of greater than 8 KT above the average/steady state wind corresponds
to the I -sigma (statistical wind profile data; Shuttle Meteorological Group (SMG), Entry
FTP 42) deviation for the maximum peak wind allowable (RSS of the peak
headJcrosswind limits). The limit of c 8 KT was chosen in order to protect for the
statistical gust factor (1-sigma) that reaches the headwind! crosswind limits.
For one APU failed, the Orbiter is one failure away from having a loss of two APU's at
touchdown. With two APU's down, the vehicle will have reduced flight control authority
(loss of hydraulic power), braking, and nose wheel steering. In order to protect from this
possible loss of control authority, crosswind peak limits are set at 10 KT for ad runways.
Greater than light turbulence is not allowed for the same control loss reasons.
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. .
FINAL 5/9/88 TRAJECTORY, GUIDANCE 4-56
.
REV DATE ~SECTION _
ALL
MISSION
PAGE NO.
72
NASA - JOHNSON SPACE CENTER
FLIGHT RULES
R RULE
~ 4-64
(Cons)
ALL
MISSION
.
. . _
LANDING SITE WEATHER CRITERIA - Continued
Gusts, peak winds above the steady state or average wind, are limited to 8 KT. This 8 KT
limit was derived from statistical data which indicated that when a 17 KT average wind
is present, the peak wind or gust is-25 KT (our headwind limit).
Loss of one APU invokes a crosswind and turbulence restriction. This part of the rule is
meant to protect the Orbiter for the loss of a second APU. With two APU's down, the
Orbiter will have reduced flight control, braking and nose wheel steering capability.
(Refer to paragraph E for an explanation of the turbulence criteria.)
C. SUN ANGLE LIMIT: SUN ON FINAL NOT WITHIN 10 DEG IN AZIMUTH AND
O TO 20 DEG ELEVATION.
These criteria was established to preclude the Sun from obstructing the crew's vision on
final approach.
D. PRECIPITATION AND THUNDERSTORM CRITERIA:
1. PRECIPITATION IS NOT ACCEPTABLE AT THE SURFACE OR ALOFT IN
THE PROXIMITY OF THE ORBITER (SEE BELOW). PRECIPITATION
INDICATIONS INCLUDE ANY OF THE FOLLOWING:
a. VISIBLE RAIN OR VIRGA
b. PRECIPITATION ECHO ON WEATHER RADAR
c. CLOUD TYPES: CUMULONIMBUS OR CUMULUS CONGESTUS
(TOWERING CUMULUS).
The Orbiter is not to encounter precipitation on any approach due to decreased visibility
andpotential damage to the TPS. Environmental design requirements for the Orbiter
were based on the avoidance of in-Qightpenetration ofthunderstorms (ref: appendix
10-10, sol X, Space Shuttle Level II Program Specification). 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).
A 10 n. mi. horizontal proximity distance was chosen based on research experience to
minimize risk due to lightning, turbulence, and wind shear and to include forecast
uncertainties.
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73
NASA - JOHNSON SPACE CENTER
FLIGHT RULES
R RULE
4-64 LANDING SITE WEATHER CRITERIA - Continued
(Cons
2. THUNDERSTORM PROXIMITY (PRE-DEORBIT AND PRELAUNCH ADA): A
SITE WILL BE NO-GO FOR LANDING IF THE THUNDERSTORM
(INCLUDING ANVIL)' LIGHTNING, OR PRECIPITATION IS WITHIN 30
NM OF THE LANDING SITE. VERTICAL CLEARANCE FROM THESE
PHENOMENA, AT THE 30 NM RANGE, MUST BE GREATER THAN 2 NM.
ADDITIONALLY, DETACHED OPAQUE THUNDERSTORM ANVILS MUST NOT
BE WITHIN 20 NM OF THE LANDING SITE, NOR WITHIN 10 NM OF
THE APPROACH PATH OUT TO A RANGE OF 30 NM.
For predeorbit or prelaunch AOA decisions (90 to 125 mire forecast), the 30 n. mi.
clearance approximates the range to the runway for straight-in approaches at an altitude
of 60K ft. Additionally, for these weather phenomena just outside the edge of the 30 n. mi.
radius, at least 2 n. mi. vertical clearance must be maintained in order to avoid triggered
lightning.
3. THUNDERSTORM PROXIMITY (PRELAUNCH RTLS AND TAL): A SITE
WILL BE NO-GO FOR LANDING IF A THUNDERSTORM (INCLUDING
ANVIL), LIGHTNING, OR PRECIPITATION IS WITHIN 20 NM OF THE
LANDING SITE OR WITHIN 10 NM OF THE APPROACH PATH TO A
RANGE OF 30 NM. VERTICAL CLEARANCE FROM THESE PHENOMENA
MUST BE GREATER THAN 2 NM ALONG THE BORDER OF THE
HORIZONTAL PROXIMITY BOUNDARY.
For the prelaunch RTLS and TAL decisions (20 to 40 minute forecast), the 20 a. mi.
radius clearance approximates a 10 n. mi. distance from each ofthe approach HAC's.
This acceptable proximity distance is reduced fro no 30 n. mi. radius due to the shorter
forecast period. The approach path between 20 n. mi. ar~d30 n. mi must also be protected
by 10 a. mi.
ADDITIONALLY, DETACHED OPAQUE THUNDERSTORM ANVILS MUST NOT
BE WITHIN 10 NM OF THE LANDING SITE, NOR WITHIN 5 NM OF THE
APPROACH PATH OUT TO A RANGE OF 30 NM.
Detached opaque thunderstorm anvils haste the potential for triggered lightning and
precipitation should the anc'`l be penetrated. Therefore, the proximity of the Orbiter from
this phenomena is primarily determined by forecast uncertainty. For the 60-to-90 minute
forecast, a 10 a. mi. margin will be maintained from the approach path and all of the
heading alignment cones ( i.e.. 20 n. mi. radius from runway). Fear the 20-tO-4n minute
forecast decisions. very little margin is prot~'cterl around the approach path: hence, the
10 n. mi. radius from the runway plus 5 n. mi. clearance along the flightpath.
THIS RULE IS CONTINUED ON THE NEXT PAGE
l A L | FINAL | 5/9/88 | TRAJECTORY, GUIDANCE I 4-58
MISSION REV | DATE T SECTION _ __
_
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74
NASA - JOHNSON SPACE CENTER
FLIGHT RULES
R RULE
~ 4-64 LANDING SITE WEATHER CRITERIA - Continued
(Cons)
4. THUNDERSTORM AVOIDANCE AFTER COMMITTED FOR LANDING: A
DISTANCE OF 5 NM HORIZONTALLY AND 2 NM ABOVE MUST BE
MAINTAINED FROM A CUMULONIMBUS CLOUD, ANVIL OR ANY OTHER
CONVECTIVE CLOUD (RAIN SHOWER) WHOSE TOP EXTENDS TO THE
-10° CELSIUS HEIGHT.
REAL-TIME THUNDERSTORM AVOIDANCE TECHNIQUES ARE LIMITED TO
RUNWAY/HAC REDESIGNATION.
NOTE: CLEARANCES WILL BE DETERMINED FROM EITHER RADAR
PRECIPITATION ECHOES OR VISUAL OBSERVATIONS.
The post-commitment avoidance clearances (5 n. mi. horizontal, 2 n. mi. vertical) were
selected to reduce impact on energy management resulting from runway redesignation
and maneuvers and at the same time ensure a reasonably low risk of a natural or
triggered lightning strike. Prohibition of penetrating cumulonimbus, cumulus congestus,
and opaque anvils is because of concern for triggered lightning and/or rain.
Reference: Weather Rules Workshop at clSC/MSFC, October, 1987.
Rule 4-62B, LANDING SITE SELECTION PRIORITIES, references this rule.
E. TURBULENCE: NOT GREATER THAN MODERATE.
Severe turbulence is undesirable due to controllability concerns. Turbulence information
comes primarily from area pilot reports. The pilots' reports follow standard definitions for
the intensity of the turbulence. The aircraft reaction for the different types of turbulence,
as found in the DOD fl fight information handbook, are defined as follows:
Light turbulence -- turbulence that momentarily causes slight, erratic changes in altitude
andlor attitude.
Moderate turbulence -- turbulence that causes changes in altitude and/or attitude, but
with the aircraft remaining in positive control at all times.
Severe turbulence -- turbulence that causes large, abrupt changes in altitude andlor
attitude. It usually causes large variations in indicated airspeed. Aircraft may be
momentarily out of control.
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RULE
75
NASA - JOHNSON SPACE CENTER
FLIGHT RULES
4-64
(Cons)
LANDING SITE WEATHER CRITERIA - Continued
F. ADDITIONAL NIGHT LANDING LIMITS:
1. WHEN AVAILABLE, A WEATHER RECONNAISSANCE AIRCRAFT WILL
PROVIDE A GO/NO-GO RECOMMENDATION FOR THE LIGHT ATTENUATION
Of THE LANDING AIDS AND THE TOUCHDOWN REGION.
2. CROSSWIND LIMIT IS c 10 KTS PEAK WIND FOR ALL NIGHT LANDING
SITES. SURFACE WIND LIMITS INCLUDE MAXIMUM GUSTS (GUSTS
MUST BE < 8 KTS ABOVE THE AVERAGE WIND)
3. WIND AND ATMOSPHERIC CONDITIONS MUST NOT REQUIRE USE OF
CLOSE-IN AIMPOINT, EXCEPT WHERE CLOSE-IN AIMPOINT PAPI's
ARE AVAILABLE.
Because the aimpoin' markings and normal geographic visual cues are not visible at
night, light attenuation ofthe landing aids and touchdown region area should be
minimal. This evaluation ofthe light attenuation will primarily depend on the weather
reconnaissance aircraft acceptability observations. If, however, an aircraft is unavailable,
then visibility will be constrained by ground observations following the daylight visibility
limits.
The crosswind limits are lower for night landings because of the increased crew workload
and visibility limitations beyond the runway edges.
A runway requiring the close-in aimpoint is NO-GO unless there is a PAPI installed.
Without the PAPI, the close-in aimpoint is not visible at night (Fit Tech 1, item 3).
4. FOR LAKEBED LANDINGS WITH ZERO fAULT TOLERANT MLS, MINIMUM
CEILING LIMIT IS 20K FT. (REF. RULE 3-41B, NAVAIDS
PRE LAUNCH REED I REMENTS, MLS ) .
For lakehed landings only, single string MLS is acceptable if ceilings are greater than
20K ft. The increased ceiling provides additional time for the crew to compensate for
navigation dispersions using visual cues. In addition. the larger area provided by the
lakebed environment makes rratJigation dispersions resulting from the possible failure of
the single-string MLS more tolerable.
Rule2-1, PRE! AUNCH CO/NO-GO REQUIREMENTS, reference this rule.
_ .
FINAL 5/9/88 TRAJECTORY, GUIDANCE
REV DATE SECTION
.
ALL
4-60
MISSION
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NASA - JOHNSON SPACE CENTER
FLIGHT RULES
4-64
(Coned)
ALL
MISSION
LANDING SITE WEATHER CRITERIA - Concluded
G. WET RUNWAY ACCEPTABILITY CONDITIONS
THE FOLLOWING CONDITIONS WILL NO-GO USE OF A SPECIFIC RUNWAY:
a. HARD SURfACE
1. STANDING WATER.
b. LAKEBED
1. MOISTURE/STANDING WATER.
2. WET/SLUSHY SURFACE MATERIAL.
3. POTHOLES.
c. ALL SURFACES
1. STRUCTURAL FAILURES (BREAKTHROUGH)
2. SNOW/ICE.
NOTE: CONDITIONS ARE ASSESSED OVER THE ENTIRE PREPARED
SURFACE OF RUNWAY
Wet lakebed runways (more than a trace of rain) are not acceptable due to the possibility of
hydroplaning and loss of brake effectiveness. Due to the large load bearing requirements
of the Orbiter, structural failures are not acceptable on any surface type. Fissures or
cracks which may lead to or be evidence of structural failures are not allowable. Wet/
slushy material is not acceptable due to the possibility of Orbiter damage from thrown
surface material lifted up by the tires. Potholes are not acceptable owing to the possible
tirelstrut damage caused by impact. For concrete surfaces, standing water may lead to
hydroplaning conditions. Snow/ice is not acceptable for any runway surface as loss of
traction results. Conditions are assessed over the entire prepared surface of the runway
due to the uncertainty of where/when standing water may go. Reference Entry FTP 42.
Rules 1-35RandJ,LANDINGSITES;2-lF.1 and3,LANDING SITE WEATHER
CRITERIA; 2-31A and D, EXTENSION DAY REQUIREMENTS; 2-81A, EXTEN-
SIONDAYGUIDELINES;341A,LANDINGSITEWEATHERCRITERIA;
4-2, LANDING SITE CONDITIONS; 4-26, PERFORMANCE BOUNDARIES;
4-62B, LANDING SITE SELECTION PRIORITIES; 4-65, DEORBIT PRIORITY FOR
EOM WEATHER; 5-27, LIMIT SHUTDOWN CONTROL; and 8-60, GNC5GOINO-GO
CRITERIA, reference this rule.
.
FINAL 5/9/88 TRAJECTORY' GUIDANCE
REV DATE SECTION
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FLIGHT RULES
RULE
R
4-65 DEORBIT PRIORITY FOR EOM WEATHER
FORECAST VIOLATIONS (REf. RULE 4-64, LANDING SITE WEATHER CRITERIA)
AT THE NOMINAL EOM TIME WILL RESULT IN SELECTION OF ONE OF THE
FOLLOWING OPTIONS LISTED IN ORDER OF PRIORITY:
A. DEORBIT TO PLS AT NOMINAL EOM TIME OR ONE ORBIT LATE TO ALTER-
NATE RUNWAYS (IF REQUIRED FOR WINDS, SUN ANGLE, OR ISOLATED
CLOUD COVERAGE).
B. DEORBIT TO PLS EARLY ON EOM DAY.
C. DEORBIT TO PLS DAILY OPPORTUNITY.
D. DEORBIT TO PLS 24 HRS LATE.
E. DEORBIT TO SLS AT NOMINAL EOM TIME.
F. RELAX WEATHER CRITERIA.
Deorbit to the primary landing site is always desirable due to convoy/ground operations
support and crew familiarity. Options 1 to 4 provide apriority list of options to deorbit to
the primary landing site. . Should it not be possible to deorbit to the primary site, the
secondary landing site will be utilized (option 5J. Weather criteria will be relaxed real
time should both the primary and secondary landing sites be unacceptable.
Rule2-200, CONTINGENCYACTIONSUMMARY, references this rule.
ALL FINAL 519/88 TRAJECTORY ~ GUIDANCE
MISSION REV DATE SEMIS
4-62
PAGE NO.
