The availability of inflight weather data to the cockpit is discussed. The need for real-time information systems to warn of hazardous weather conditions is emphasized. It is suggested that the Weather Service severe weather radar network be collocated with the FAA radar to provide information for real-time decision making

Gatlin, H. G.

English

NASA Technical Reports Server

NEEDED WEATHER INFORMATION WHERE IT BELONGS--IN THE COCKPIT 
H .  Grady Gatlin 
Air Transport Association of America 
Mr. Gatl in 's  presentation began w i t h  an i l l u s t r a t i v e  s l i de  show 
emphasizing the sudden and unexpected severe weather encounter. The 
editors have attempted t o  reproduce this i n  p r i n t  f o r  the benefit o f  
the reader. 
J e t  engine sounds begin . 
Captain: "There wasn ' t  
any weather l ike  this 
i n  the forecast!" 
F i r s t  Officer: "This 
radar ' s  not p a i n t i n g  a 
very good pi cture--the 
controller  doesn't  have 
i t  ei ther!" 
d 37 
https://ntrs.nasa.gov/search.jsp?R=19800006377 2020-03-21T01:59:56+00:00Z
Captain: "We're going 
t o  have t o  go r ight  
th rough .  . . I' 
Fi r s t  Officer: " I t  
looks be t te r  there-- 
l e t ' s  t r y  it!" 
Small lightning flash. 
J 38 
Thunder sound 
over engine 
noise . 
Rain noise on metal. 
Fi rs t  Officer: 
"There's the ra in!"  
Engine sound loud as 
scene goes to  exterior  
of airplane. 
i 39 
Captain: 
now 1 " 
"That s hai 1 
Thunder. 
Sounds lessen. 
1 40 
3 ig  lightning flash.  
Loud thunder. 
Thunder rol l ing,  
silence. 
then 
I assume every p i l o t  has had a similar  experience and wondered, 
"How i n  the hell d i d  I get in to  a s i tuat ion l ike  this!" 
Or perhaps he has been unfortunate enough to  be involved i n  weather- 
related accident investigations at tr ibuted to  wind shear, turbulence, 
or other hazardous weather conditions--accidents tha t  might  have been 
avoided i f  the p i l o t  had had needed weather information where i t  belongs-- 
in the cockpit. 
l e t ' s  look a t  "Needed Weather Information Where I t  Belongs--In the 
Cockpit. 'I 
So as  the Flight Operations overview fo r  t h i s  workshop 
d 41 
B u t  who says we need any information i n  the cockpi 
for  one, the FAA! They proposed a rule i n  1976 which  
implemented on December 31, 1977, which says, i n  
weather reports and forecasts of weather phenome 
safety of f l i g h t ,  such as c lear  a i r  turbulence, t h u n d  
a l t i tude  wind shear fo r  each route t o  be flown and a i  
must be provided to  the pilot-in-command by the a i r l i  
before and d u r i n g  each f l i g h t .  
accidents i n  the industry t e s t i f i e s  t o  the need for accurate 
weather being available t o  the pilot--66 a t  JFK; New Hope, Ge 
S t .  Louis; F i j i ;  e tc .  All too often the information i n  the s 
never reaches the cockpit where i t ' s  needed. 
Even without the regulations , however, the number of weather-re1 ated 
time 
9 
The FAA categorizes weather as hazardous when i t  is  dangerous t o  
a i r c r a f t ,  passengers, and crew and i s  generally associated with: 
0 Thunderstorms 
0 Turbulence (c lear  air--mountain waves) 
Icing 
0 Wind shear 
0 Ceiling and v i s i b i l i t y  (deteriorat ing) 
0 Wind (sustained 30 knots or  greater)  
Routine weather is categorized as: 
Air temperature 
Dew p o i n t  
Atmospheric pressure 
Cloud height and cover 
Wind direction and velocity 
Peak gusts 
RVR 
Preci p i  t a t i  on 
A1 timeter se t t ings  
Winds and temperatures a l o f t  
To comply with the F A R ' S ,  a p i lo t  as stated must be provided w i t h  
available hazardous and routine weather information before and d u r i n g  
f l i gh t  t o  permit planning and execution i n  a safe and e f f i c i en t  manner, 
and the a i r l i n e  dispatcher (even many, many miles away) i s  t o  furnish i t .  
Today, the a i r l i ne s '  means of providing weather information t o  the 
p i lo t  i s  involved w i t h  computerized f l i gh t  plans and weather packages. 
As an example, one of our major a i r l ines  has a d i rec t  communications 
link between the FAA Weather Message Switching Center i n  Kansas City and 
the a i r l i n e ' s  reservations computer. Weather information is stored i n  
the computer and i s  available fo r  immediate display and/or reproduction 
t o  Dispatch, Meteorology,and any other location having a CRT or a d i rec t  
i 42 
link t o  i t s  central computers. 
the National Meteorological Center a t  Suitland, Maryland, provides wind 
and temperature a l o f t  forecasts.  
In addition, another d i rect  l i n k  from 
T h i s  stored information is  used t o  provide F l i g h t  Dispatch a com- 
puterized f l i g h t  plan along the FAA preferential route before the crew 
arrives a t  the a i rpor t ,  and i f  the preferential route is  longer by six 
minutes o r  more, another minimum route o r  minimum cost plan will auto- 
matically be provided. 
On his a r r iva l ,  the p i lo t  reviews posted weather information that  
contains past,  present, and forecast  weather conditions. B u t  more i m-  
portantly, attached t o  his f l i gh t  plan for  review and use will be a 
computerized weather package. T h i s  package is sometimes called "The 
Command Weather Document." T h i s  document i s  speci f ica l ly  tai lored fo r  
each f l i g h t ,  p rov id ing  NOTAMS, f i e ld  conditions, hourly sequences and 
forecasts f o r  t h a t  part icular  route, thereby eliminating a1 1 extraneous 
information. I t  is  possible, however, fo r  the p i lo t  to  request addi- 
tional weather on the CRT o r  hard-copy printouts. 
and desirable fo r  the p i l o t  t o  receive verbal briefings from the d i s-  
patchers or meteorologists when weather conditions cal l  for  i t .  
A t  this p o i n t  the p i l o t  has been given access t o  a l l  the available 
weather information i n  the system and should be able t o  conduct a safe 
f l i gh t  insofar as weather is concerned. Perhaps we should take a closer 
look a t  where a l l  this information comes from, how i t  was collected and 
distr ibuted,  and whether i t  i s  currently v a l i d  concerning f l i gh t  safety. 
I t  is also possible 
The current Aviation Weather System is  a collection of functionally 
independent elements employing primarily a slow (100 WPM) and medium 
(1200 WPM) speed te lepr in te r  distr ibution network coupled w i t h  a slow- 
speed electrowriter  system which is  used t o  transmit both weather and 
a i rpor t  data. 
intensive, and not capable of meeting the demand for  timely and accurate 
weather information needed by the a i r l i ne s  t o  operate i n  the National 
Airspace System. As an aside comment a t  this time, i t  should be pointed 
out t h a t  the a i r l ines  are  closely following developments and planned 
implementation dates of the Automation of Field Observations and Services 
(AFOS) Program by the National Weather Service, which will provide the 
graphic forms via CRT. However, cost of ins ta l l a t ion ,  equipment, and 
needed change-over c i rcu i t ry  are  only a few examples of a myriad of ques- 
tions to  which a i r l ines  must have an answer before adopting a position fo r  
o r  against AFOS. As of now, a i r l i ne s  are  working closely w i t h  segments of 
NWS i n  order to  ascertain firm dates for reduction of some of the cur- 
rent facsimile c i rcu i t s  known more familiarly as Forecast Office Fac- 
simile (FOFAX) and National and Aviation Meteorological Facsimile Network 
(NAMFAX) . 
be made available on NWS means t o  meet stated a i r l i ne  requirements for  
receipt of weather data from the s a t e l l i t e s .  
Basically, the system can be considered slow, labor 
Additional l y  , i t  is of paramount importance that  information 
J 43 
Returning t o  the real world of today, meteorological data is collec- 
ted by the National Weather Service, Federal Aviation Administration, 
Department of Defense, a i r  ca r r ie r s ,  and contract observers; and this 
data includes surface observations , upper a i r  soundings, and radar. 
The FAA is  responsible for 35% of this information as well as the d i s-  
t r i b u t i o n  of PIREPS while the National Environmental S a t e l l i t e  Service 
is  the source of a l l  available s a t e l l i t e  weather information. 
After a l l  this data has been processed through the National Meteor- 
ological Center and the Air Force Global Weather Central, i t  i s  d i s t r i -  
buted t o  the users by the FAA through the Weather Message Switching 
Center and by the National Weather Service u s i n g  facsimile fo r  graphic 
weather i n forma t i on. 
T h i s  system is  time consuming, and although i t  f u l f i l l s  the FAR 
requirements, i t  does not adequately contribute t o  safety of  f l i gh t  from 
hazardous weather conditions. In fact ,  since upper a i r  data are  collec- 
ted only every 12 hours,  the inadequate number of observations leads t o  
errors i n  the winds a l o f t  forecasts used fo r  f l i g h t  planning and conse- 
quently t o  less  than optimum fuel consumption. 
After takeoff,  airborne radar weather reports from other f l i gh t s  
and  a i r  t r a f f i c  control become the prime source of weather information 
en route and d u r i n g  approach and f inal  landing. Unfortunately, con- 
t ro l l e r s  i n  the Air Route Traffic Control Centers (ARTCC's) and approach 
control obtain t he i r  weather information from the same source as the 
a i r l ines ,  which is not timely enough for  real-time decision making by 
the p i lo t  o r  controller.  In an e f fo r t  t o  help decrease the time between 
when the hazardous weather conditions are observed and when they are 
received by the p i lo t  of the a i r c r a f t  concerned, the FAA,in collabora- 
t i o n  w i t h  the NWS,activated Center Weather Service Units (CWSU) a t  13 
ARTCC's throughout the country d u r i n g  l a t e  1977 and early 1978. Addi- 
t ional ly ,  the NWS ins t i tu ted  the Convective SIGMET program w i t h  FAA 
broadcasting Convective SIGMET information over i t s  Visual Omni  Range/ 
Transcribed Weather Broadcasts (VOR/TWEB) outlets .  During the i n i t i a l  
tes t ing of the Convective SIGMET program i t  became apparent t o  the a i r -  
l ines t h a t  the requirement t o  p l o t  locations of data on s ignif icant  
e weather on charts w i t h i n  the cockpit was both burdensome and time con- 
suming  and s t i l l  was n o t  close enough t o  real time t o  be useful. Sub-  
sequently, following meetings with ATA, a i r l i ne s ,  and other segments 
of industry, NWS and FAA have revised the program, t h u s  eliminating the 
detailed cockpit plott ing requirement specified ea r l i e r .  We are watch- 
i n g  closely both the CWSU and the Convective SIGMET programs, 
PIREP's are  a source of real-time hazardous weather conditions. 
Since hazardous weather i s  subject to  r a p i d  change, immediate dissemin- 
a t i o n  o f  PIREP's i s  an absolute necessity; however, the majority are  
not transmitted beyond the receiving f a c i l i t y ,  and those t h a t  are 
transmitted take so long over the antiquated communications system that  
they are  of no value t o  the user. 
J 44 
Since a i rpor t  and a i r  route surveillance radar are  optimized fo r  
a i r c r a f t  detection and have limited capabil i ty t o  detect  and display 
storm intensi ty  variations, i t  does not provide accurate or  suf f ic ien t  
defini t ion of weather areas fo r  controllers  t o  provide re l iable  vector- 
i n g  or advisory services to  the pilots .  
The  National Weather Service operates a network of weather radar 
s ta t ions  eas t  of the Rockies t o  detect  and observe severe weather. They 
are  not collocated w i t h  FAA radars and except fo r  special projects are  
not remoted t o  FAA ATC f a c i l i t i e s .  Data from weather radars is  used by 
the National Severe Weather Forecast Center i n  Kansas City where a radar 
summary chart is constructed and transmitted by facsimile. Again, this 
valuable information i s  not available t o  the pi lo ts  f o r  real-time deci- 
sion making. 
In  f a c t ,  the only real-time information avaiiable t o  the cockpit 
is from the FAA control towers which provide w i n d ,  a l t imeter  se t t ings  
and RVR on f i n a l  approach. Even the Automated Terminal Information 
Service (ATIS) i s  subject t o  p r o v i d i n g  obsolete information when con- 
t r o l l e r s '  workloads are  heavy and weather conditions are changing 
rapidly. 
What weather information is  needed i n  the cockpit? In f l i gh t  
planning we need current winds  a lo f t .  Observations every 12 hours a re  
inadequate; we suggest t h a t  such observations should be made every six 
hours. 
En route and i n  the terminal areas the p i l o t  needs real-time 
hazardous weather information and he needs i t  di rect ly  from the observers. 
As discussed, the current Aviation Weather System has the in fo r-  
mation, b u t  i t  is  not available i n  the cockpit on a real-time basis .  
Currently the FAA has developed an Aviation Weather System Prelim- 
inary Program Plan designed t o  improve their capabil i ty fo r  providing 
hazardous and routine weather information t o  p i lo ts  and controllers. 
The plan i s  very comprehensive and the FAA should be complimented fo r  
itsthoroughness. I t  iden t i f i es  the problems and proposes solutions, 
and when i t  is  implemented our Aviation Weather System will have 
e f f ic ien t  a i r  operations. For this reason we wholeheartedly support 
t h i s  program and a l l  the technological improvements i n  the plan w i t h  
one exception. Although the technological capabil i ty will be available, 
the plan is i n  the future and we need something now, part icularly real-  
time hazardous weather information i n  the cockpit. 
As long as the f l i g h t  dispatcher is  held responsible fo r  providing 
en route hazardous weather t o  the p i l o t  and u n t i l  the FAA assumes some 
responsibil i ty for  real-time information t o  the cockpit, a l l  the programs, 
technological improvements, and money spent will  not achieve their fu l l  
potential i n  providing safe transportation t o  the traveling public! 
Before I close I want t o  mention my indebtedness t o  Cgptain J. E. 
Frankum, Vice President- F l i g h t  Operations, Trans World Airlines fo r  
some of the material I have used and for  his assistance i n  this preparation. 
d 
45 


Needed weather information where it belongs; in the cockpit

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