What role did the RAT (Ram Air Turbine) play on US Airways flight 1549?

Clash Royale CLAN TAG#URR8PPP

up vote
15
down vote

favorite

An article in June 2018 Flying Magazine regarding the RAT by a Rob Mark explains that Capt. Sullunberger deployed the RAT for additional power to guide the plane down to the safe ditching on the Hudson River.

My understanding is, according to all the narratives, the book, and the movie, what saved the day (with the exception of the amazing skills of the flight crew) was the immediate starting of the APU by Capt. Sullenberger that was not even on the QRM check list,...and not the RAT.

I am wondering if both (APU and RAT) were used on that flight or the APU only? And if so, has Flying Magazine author made a mistake?

aircraft-performance apu rat

share|improve this question

edited Sep 6 at 20:09

chicks

11515

asked Sep 4 at 18:10

Hercules-63

20118

add a comment | 

up vote
15
down vote

favorite

An article in June 2018 Flying Magazine regarding the RAT by a Rob Mark explains that Capt. Sullunberger deployed the RAT for additional power to guide the plane down to the safe ditching on the Hudson River.

My understanding is, according to all the narratives, the book, and the movie, what saved the day (with the exception of the amazing skills of the flight crew) was the immediate starting of the APU by Capt. Sullenberger that was not even on the QRM check list,...and not the RAT.

I am wondering if both (APU and RAT) were used on that flight or the APU only? And if so, has Flying Magazine author made a mistake?

aircraft-performance apu rat

share|improve this question

edited Sep 6 at 20:09

chicks

11515

asked Sep 4 at 18:10

Hercules-63

20118

add a comment | 

up vote
15
down vote

favorite

up vote
15
down vote

favorite

An article in June 2018 Flying Magazine regarding the RAT by a Rob Mark explains that Capt. Sullunberger deployed the RAT for additional power to guide the plane down to the safe ditching on the Hudson River.

My understanding is, according to all the narratives, the book, and the movie, what saved the day (with the exception of the amazing skills of the flight crew) was the immediate starting of the APU by Capt. Sullenberger that was not even on the QRM check list,...and not the RAT.

I am wondering if both (APU and RAT) were used on that flight or the APU only? And if so, has Flying Magazine author made a mistake?

aircraft-performance apu rat

share|improve this question

edited Sep 6 at 20:09

chicks

11515

asked Sep 4 at 18:10

Hercules-63

20118

An article in June 2018 Flying Magazine regarding the RAT by a Rob Mark explains that Capt. Sullunberger deployed the RAT for additional power to guide the plane down to the safe ditching on the Hudson River.

My understanding is, according to all the narratives, the book, and the movie, what saved the day (with the exception of the amazing skills of the flight crew) was the immediate starting of the APU by Capt. Sullenberger that was not even on the QRM check list,...and not the RAT.

I am wondering if both (APU and RAT) were used on that flight or the APU only? And if so, has Flying Magazine author made a mistake?

aircraft-performance apu rat

share|improve this question

edited Sep 6 at 20:09

chicks

11515

asked Sep 4 at 18:10

Hercules-63

20118

share|improve this question

share|improve this question

edited Sep 6 at 20:09

chicks

11515

edited Sep 6 at 20:09

chicks

11515

edited Sep 6 at 20:09

chicks

11515

11515

asked Sep 4 at 18:10

Hercules-63

20118

asked Sep 4 at 18:10

Hercules-63

20118

asked Sep 4 at 18:10

Hercules-63

20118

20118

add a comment | 

add a comment | 

1 Answer
1

active

oldest

votes

up vote
26
down vote



accepted

The full NTSB report can be found here and is the official source of information on the incident. According to that report Sullunberger did immediately start the APU which did deliver power and they determined they did not need to manually deploy the RAT. However the onboard systems deployed it automatically likely as a result of the initial power loss and sufficient airspeed (over 100Kts).

Regarding step e, the pilots stated that they determined that
electrical power was established and, therefore, that the RAT did not
need to be manually deployed. Further, immediately after the loss of
engine thrust, the captain started the APU.

This can be heard in the official transcript

At 1527:14, the first officer stated, “uh oh,” followed by the captain
stating, “we got one rol- both of ‘em rolling back.” At 1527:18, the
cockpit area microphone (CAM) recorded the beginning of a rumbling
sound.

At 1527:19, the captain stated, “[engine] ignition, start,”
and, about 2 seconds later, “I’m starting the APU [auxiliary power
unit].”5

At 1527:23, the captain took over control of the airplane,
stating, “my aircraft.”

However the RAT was found to be deployed (due to the automatic systems on the aircraft) when the airframe was recovered

When all of the airplane’s electrical power is lost and the airplane
has an airspeed greater than 100 knots (kts), the RAT will
automatically deploy and begin providing electrical power. The RAT was
found in the extended position when the airplane was recovered from
the water.

share|improve this answer

edited Sep 4 at 21:42

answered Sep 4 at 18:27

Dave

56.5k3101207

• 
  
  
  

  
  4
  

  
  
  
  
  
  

  
  How can a pilot extend rat when there is no power? Which is the problem rat tries to solve. (afaik) Is there a handle directly attached to it?
  – Ali Erdem
  Sep 4 at 19:09
  
  

  
  
  
  


• 
  
  
  

  
  8
  

  
  
  
  
  
  

  
  @AliErdem: aviation.stackexchange.com/questions/1583/…
  – BowlOfRed
  Sep 4 at 19:22
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  If I recall correctly, you do not need power to deploy a RAT, you need power to retract it. Like brakes on a truck or a train, the default state is actually deployed, not stowed.
  – MichaelK
  Sep 5 at 7:37
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  RATs are normally spring-deployed (to get them out fast), and are held in by a latch. You need battery power to a solenoid to release the latch - twang! (They are retracted by hand to ensure the latch is hlding correctly, to avoid a twang at the wrong time.)
  – RAC
  Sep 5 at 7:54
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Thank you for linking the report. It was an interresting read.
  – Daan van Hoek
  Sep 5 at 14:06
  

  
  
  
  

add a comment | 

Your Answer

StackExchange.ifUsing("editor", function ()
return StackExchange.using("mathjaxEditing", function ()
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
);
);
, "mathjax-editing");

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "528"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
convertImagesToLinks: false,
noModals: false,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);

 

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name Email

StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2faviation.stackexchange.com%2fquestions%2f54820%2fwhat-role-did-the-rat-ram-air-turbine-play-on-us-airways-flight-1549%23new-answer', 'question_page');

);

Post as a guest

Name Email

1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

active

oldest

votes

active

oldest

votes

up vote
26
down vote



accepted

The full NTSB report can be found here and is the official source of information on the incident. According to that report Sullunberger did immediately start the APU which did deliver power and they determined they did not need to manually deploy the RAT. However the onboard systems deployed it automatically likely as a result of the initial power loss and sufficient airspeed (over 100Kts).

Regarding step e, the pilots stated that they determined that
electrical power was established and, therefore, that the RAT did not
need to be manually deployed. Further, immediately after the loss of
engine thrust, the captain started the APU.

This can be heard in the official transcript

At 1527:14, the first officer stated, “uh oh,” followed by the captain
stating, “we got one rol- both of ‘em rolling back.” At 1527:18, the
cockpit area microphone (CAM) recorded the beginning of a rumbling
sound.

At 1527:19, the captain stated, “[engine] ignition, start,”
and, about 2 seconds later, “I’m starting the APU [auxiliary power
unit].”5

At 1527:23, the captain took over control of the airplane,
stating, “my aircraft.”

However the RAT was found to be deployed (due to the automatic systems on the aircraft) when the airframe was recovered

When all of the airplane’s electrical power is lost and the airplane
has an airspeed greater than 100 knots (kts), the RAT will
automatically deploy and begin providing electrical power. The RAT was
found in the extended position when the airplane was recovered from
the water.

share|improve this answer

edited Sep 4 at 21:42

answered Sep 4 at 18:27

Dave

56.5k3101207

• 
  
  
  

  
  4
  

  
  
  
  
  
  

  
  How can a pilot extend rat when there is no power? Which is the problem rat tries to solve. (afaik) Is there a handle directly attached to it?
  – Ali Erdem
  Sep 4 at 19:09
  
  

  
  
  
  


• 
  
  
  

  
  8
  

  
  
  
  
  
  

  
  @AliErdem: aviation.stackexchange.com/questions/1583/…
  – BowlOfRed
  Sep 4 at 19:22
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  If I recall correctly, you do not need power to deploy a RAT, you need power to retract it. Like brakes on a truck or a train, the default state is actually deployed, not stowed.
  – MichaelK
  Sep 5 at 7:37
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  RATs are normally spring-deployed (to get them out fast), and are held in by a latch. You need battery power to a solenoid to release the latch - twang! (They are retracted by hand to ensure the latch is hlding correctly, to avoid a twang at the wrong time.)
  – RAC
  Sep 5 at 7:54
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Thank you for linking the report. It was an interresting read.
  – Daan van Hoek
  Sep 5 at 14:06
  

  
  
  
  

add a comment | 

up vote
26
down vote



accepted

The full NTSB report can be found here and is the official source of information on the incident. According to that report Sullunberger did immediately start the APU which did deliver power and they determined they did not need to manually deploy the RAT. However the onboard systems deployed it automatically likely as a result of the initial power loss and sufficient airspeed (over 100Kts).

Regarding step e, the pilots stated that they determined that
electrical power was established and, therefore, that the RAT did not
need to be manually deployed. Further, immediately after the loss of
engine thrust, the captain started the APU.

This can be heard in the official transcript

At 1527:14, the first officer stated, “uh oh,” followed by the captain
stating, “we got one rol- both of ‘em rolling back.” At 1527:18, the
cockpit area microphone (CAM) recorded the beginning of a rumbling
sound.

At 1527:19, the captain stated, “[engine] ignition, start,”
and, about 2 seconds later, “I’m starting the APU [auxiliary power
unit].”5

At 1527:23, the captain took over control of the airplane,
stating, “my aircraft.”

However the RAT was found to be deployed (due to the automatic systems on the aircraft) when the airframe was recovered

When all of the airplane’s electrical power is lost and the airplane
has an airspeed greater than 100 knots (kts), the RAT will
automatically deploy and begin providing electrical power. The RAT was
found in the extended position when the airplane was recovered from
the water.

share|improve this answer

edited Sep 4 at 21:42

answered Sep 4 at 18:27

Dave

56.5k3101207

• 
  
  
  

  
  4
  

  
  
  
  
  
  

  
  How can a pilot extend rat when there is no power? Which is the problem rat tries to solve. (afaik) Is there a handle directly attached to it?
  – Ali Erdem
  Sep 4 at 19:09
  
  

  
  
  
  


• 
  
  
  

  
  8
  

  
  
  
  
  
  

  
  @AliErdem: aviation.stackexchange.com/questions/1583/…
  – BowlOfRed
  Sep 4 at 19:22
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  If I recall correctly, you do not need power to deploy a RAT, you need power to retract it. Like brakes on a truck or a train, the default state is actually deployed, not stowed.
  – MichaelK
  Sep 5 at 7:37
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  RATs are normally spring-deployed (to get them out fast), and are held in by a latch. You need battery power to a solenoid to release the latch - twang! (They are retracted by hand to ensure the latch is hlding correctly, to avoid a twang at the wrong time.)
  – RAC
  Sep 5 at 7:54
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Thank you for linking the report. It was an interresting read.
  – Daan van Hoek
  Sep 5 at 14:06
  

  
  
  
  

add a comment | 

up vote
26
down vote



accepted

up vote
26
down vote



accepted

The full NTSB report can be found here and is the official source of information on the incident. According to that report Sullunberger did immediately start the APU which did deliver power and they determined they did not need to manually deploy the RAT. However the onboard systems deployed it automatically likely as a result of the initial power loss and sufficient airspeed (over 100Kts).

Regarding step e, the pilots stated that they determined that
electrical power was established and, therefore, that the RAT did not
need to be manually deployed. Further, immediately after the loss of
engine thrust, the captain started the APU.

This can be heard in the official transcript

At 1527:14, the first officer stated, “uh oh,” followed by the captain
stating, “we got one rol- both of ‘em rolling back.” At 1527:18, the
cockpit area microphone (CAM) recorded the beginning of a rumbling
sound.

At 1527:19, the captain stated, “[engine] ignition, start,”
and, about 2 seconds later, “I’m starting the APU [auxiliary power
unit].”5

At 1527:23, the captain took over control of the airplane,
stating, “my aircraft.”

However the RAT was found to be deployed (due to the automatic systems on the aircraft) when the airframe was recovered

When all of the airplane’s electrical power is lost and the airplane
has an airspeed greater than 100 knots (kts), the RAT will
automatically deploy and begin providing electrical power. The RAT was
found in the extended position when the airplane was recovered from
the water.

share|improve this answer

edited Sep 4 at 21:42

answered Sep 4 at 18:27

Dave

56.5k3101207

The full NTSB report can be found here and is the official source of information on the incident. According to that report Sullunberger did immediately start the APU which did deliver power and they determined they did not need to manually deploy the RAT. However the onboard systems deployed it automatically likely as a result of the initial power loss and sufficient airspeed (over 100Kts).

Regarding step e, the pilots stated that they determined that
electrical power was established and, therefore, that the RAT did not
need to be manually deployed. Further, immediately after the loss of
engine thrust, the captain started the APU.

This can be heard in the official transcript

At 1527:14, the first officer stated, “uh oh,” followed by the captain
stating, “we got one rol- both of ‘em rolling back.” At 1527:18, the
cockpit area microphone (CAM) recorded the beginning of a rumbling
sound.

At 1527:19, the captain stated, “[engine] ignition, start,”
and, about 2 seconds later, “I’m starting the APU [auxiliary power
unit].”5

At 1527:23, the captain took over control of the airplane,
stating, “my aircraft.”

However the RAT was found to be deployed (due to the automatic systems on the aircraft) when the airframe was recovered

When all of the airplane’s electrical power is lost and the airplane
has an airspeed greater than 100 knots (kts), the RAT will
automatically deploy and begin providing electrical power. The RAT was
found in the extended position when the airplane was recovered from
the water.

share|improve this answer

edited Sep 4 at 21:42

answered Sep 4 at 18:27

Dave

56.5k3101207

share|improve this answer

share|improve this answer

edited Sep 4 at 21:42

edited Sep 4 at 21:42

edited Sep 4 at 21:42

answered Sep 4 at 18:27

Dave

56.5k3101207

answered Sep 4 at 18:27

Dave

56.5k3101207

answered Sep 4 at 18:27

Dave

56.5k3101207

56.5k3101207

• 
  
  
  

  
  4
  

  
  
  
  
  
  

  
  How can a pilot extend rat when there is no power? Which is the problem rat tries to solve. (afaik) Is there a handle directly attached to it?
  – Ali Erdem
  Sep 4 at 19:09
  
  

  
  
  
  


• 
  
  
  

  
  8
  

  
  
  
  
  
  

  
  @AliErdem: aviation.stackexchange.com/questions/1583/…
  – BowlOfRed
  Sep 4 at 19:22
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  If I recall correctly, you do not need power to deploy a RAT, you need power to retract it. Like brakes on a truck or a train, the default state is actually deployed, not stowed.
  – MichaelK
  Sep 5 at 7:37
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  RATs are normally spring-deployed (to get them out fast), and are held in by a latch. You need battery power to a solenoid to release the latch - twang! (They are retracted by hand to ensure the latch is hlding correctly, to avoid a twang at the wrong time.)
  – RAC
  Sep 5 at 7:54
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Thank you for linking the report. It was an interresting read.
  – Daan van Hoek
  Sep 5 at 14:06
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  4
  

  
  
  
  
  
  

  
  How can a pilot extend rat when there is no power? Which is the problem rat tries to solve. (afaik) Is there a handle directly attached to it?
  – Ali Erdem
  Sep 4 at 19:09
  
  

  
  
  
  


• 
  
  
  

  
  8
  

  
  
  
  
  
  

  
  @AliErdem: aviation.stackexchange.com/questions/1583/…
  – BowlOfRed
  Sep 4 at 19:22
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  If I recall correctly, you do not need power to deploy a RAT, you need power to retract it. Like brakes on a truck or a train, the default state is actually deployed, not stowed.
  – MichaelK
  Sep 5 at 7:37
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  RATs are normally spring-deployed (to get them out fast), and are held in by a latch. You need battery power to a solenoid to release the latch - twang! (They are retracted by hand to ensure the latch is hlding correctly, to avoid a twang at the wrong time.)
  – RAC
  Sep 5 at 7:54
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Thank you for linking the report. It was an interresting read.
  – Daan van Hoek
  Sep 5 at 14:06
  

  
  
  
  

4

4

How can a pilot extend rat when there is no power? Which is the problem rat tries to solve. (afaik) Is there a handle directly attached to it?
– Ali Erdem
Sep 4 at 19:09

How can a pilot extend rat when there is no power? Which is the problem rat tries to solve. (afaik) Is there a handle directly attached to it?
– Ali Erdem
Sep 4 at 19:09

8

8

@AliErdem: aviation.stackexchange.com/questions/1583/…
– BowlOfRed
Sep 4 at 19:22

@AliErdem: aviation.stackexchange.com/questions/1583/…
– BowlOfRed
Sep 4 at 19:22

1

1

If I recall correctly, you do not need power to deploy a RAT, you need power to retract it. Like brakes on a truck or a train, the default state is actually deployed, not stowed.
– MichaelK
Sep 5 at 7:37

If I recall correctly, you do not need power to deploy a RAT, you need power to retract it. Like brakes on a truck or a train, the default state is actually deployed, not stowed.
– MichaelK
Sep 5 at 7:37

2

2

RATs are normally spring-deployed (to get them out fast), and are held in by a latch. You need battery power to a solenoid to release the latch - twang! (They are retracted by hand to ensure the latch is hlding correctly, to avoid a twang at the wrong time.)
– RAC
Sep 5 at 7:54

RATs are normally spring-deployed (to get them out fast), and are held in by a latch. You need battery power to a solenoid to release the latch - twang! (They are retracted by hand to ensure the latch is hlding correctly, to avoid a twang at the wrong time.)
– RAC
Sep 5 at 7:54

1

1

Thank you for linking the report. It was an interresting read.
– Daan van Hoek
Sep 5 at 14:06

Thank you for linking the report. It was an interresting read.
– Daan van Hoek
Sep 5 at 14:06

add a comment | 

 

draft saved

draft discarded

 

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name Email

StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2faviation.stackexchange.com%2fquestions%2f54820%2fwhat-role-did-the-rat-ram-air-turbine-play-on-us-airways-flight-1549%23new-answer', 'question_page');

);

Post as a guest

Name Email

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name Email

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name Email

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name Email

Name Email

Name

Email

Name Email

Name

Email