Should We Recite al-Fatihah behind the Imam?
Question

My question relates to the correct manner of praying Farz salat behind an Imam, specifically the recital of surah Al-Fatihah.
1. Is it obligatory on us to quietly recite surah Al-Fatihah whilst the Imam recites it aloud, during the first and second rak`ah of a farz prayer?
2. Is it obligatory on us to recite the surah Al-Fatihah in the same situation but in the third and/or fourth rak`ah, ie., the Imam is silent in these rak`ahs?
This question arises due to our community's wish to correct our method of praying. There are two opinions amongst us, one being that when the Imam leads a prayer, whether he recites them aloud (1st and 2nd rak`ahs) or is silent (3rd and 4th rak`ahs) we must only listen; whilst others comment that without the recitation of surah Al-Fatihah, whether recited by the Imam or not, a prayer is not valid.
Please advise with as much factual evidence as possible.
Praise be to Allah.Reciting al-Fatihah is one of the essential parts of the prayer, and is to be recited in each rak`ah both by the imam and by those who are being led by him, because the Prophet (peace and blessings of Allah be upon him) said: “There is no prayer for the one who does not recite the Opening of the Book [i.e., al-Fatihah].” (Narrated by al-Bukhari, 714). 
With regard to one who is following an imam reciting al-Fatihah behind the imam in a prayer where Quran is to be recited out loud, there are two scholarly opinions. 

The first opinion is that it is obligatory, the evidence for that being the general meaning of the hadith of the Prophet (peace and blessings of Allah be upon him): “There is no prayer for the one who does not recite the Opening of the Book [i.e., al-Fatihah].” And because when the Prophet (peace and blessings of Allah be upon him) taught the one who had not prayed properly, he told him to recite al-Fatihah . 

It was narrated in a sahih report that the Prophet (peace and blessings of Allah be upon him) used to recite it in every rak`ah. Al-Hafiz ibn Hajar said in Fath al-Bari: “It was proven that permission was given to the one who is praying behind an imam to recite al-Fatihah in prayers in which Quran is to be recited out loud, without any exceptions. That is what was narrated by al-Bukhari in Juz al-Qira-ah, and by al-Tirmidhi, Ibn Hibban and others, from Makhul from Mahmud ibn al-Rabi’ from ‘Ubadah, that the Prophet (peace and blessings of Allah be upon him) stumbled in his recitation in Fajr, and when he finished he said, “Perhaps you recite behind your imam?” They said, “Yes,” He said, “Do not do that, except for the Opening of the Book (al-Faithah), for there is no prayer for the one who does not recite it.” 

The second opinion is that the recitation of the imam is also the recitation of the one who is praying behind him. The evidence for that is the ayah (interpretation of the meaning): 

“So, when the Quran is recited, listen to it, and be silent that you may receive mercy” [al-A’raf 7:204]
Ibn Hajar said: “Those who say that (the one who is praying behind an imam) does not have to recite it in prayers where Quran is to be recited out loud, such as the Malikis, quote as evidence the hadith, ‘When he recites then listen attentively.’ This is a sahih hadith which was narrated by Muslim from Abu Musa al-‘Ash’ari.” 
Those who say that it is obligatory say that it should be recited after the imam has finished reciting al-Fatihah and before he starts to recite another surah, or that it should be recited when the imam pauses. Ibn Hajar said: “He should listen when the imam is reciting, and recite it when he is silent.” 
Shaykh Ibn Baz said, “What is meant by when the imam pauses is when he pauses during al-Fatihah or after reciting it, or in the surah that he recites after it. If the imam does not pause, then the one who is praying behind him has to recite al-Fatihah even if the imam is reciting, according to the more correct of the two scholarly opinions.” (See Fatawa al-Shaykh Ibn Baz, vol. 11, p. 221) 
The Standing Committee was asked a similar question and replied as follows: 
“The correct scholarly opinion is that it is obligatory to recite al-Fatihah when praying alone and it is obligatory upon the imam and those whom he is leading both in prayers where Quran is to be recited out loud and when it is to be recited silently, because of the soundness and specific nature of the texts which indicate that. The verse (interpretation of the meaning): 
“So, when the Quran is recited, listen to it, and be silent that you may receive mercy” [al-A’raf 7:204] is general in meaning. The hadith, “When the Quran is recited then listen attentively” is general and applies both to al-Fatihah and other surahs. These two texts are general in meaning, and the following hadith refers to an exception to that rule: 
“There is no prayer for the one who does not recite the Opening of the Book.” Thus we may reconcile all the proven evidence. The hadith “The recitation of the imam is the recitation of the one who is praying behind him” is weak. It is not correct to say that the Amin of the congregation to the imam’s recitation of al-Fatihah takes the place of their own recitation. The differences of opinion among the scholars concerning this matter should not be taken as a means to hate one another, and to divide and turn our backs on one another. Rather you have to study the matter in more detail and find out more. If one of you is following a scholar who says that the one who is praying behind an imam has to recite al-Fatihah during prayers in which Quran is to be recited out loud, and others are following a scholar who says that they must be silent and listen to the imam in prayers where Quran is to be recited out loud, and that the imam’s recitation of al-Fatihah is sufficient, there is nothing wrong with that. There is no need for one group to denounce the other, or to hate one another because of that. 
They have to be open-minded about differences of opinion among the scholars, and about the reasons for that, and ask Allah to guide them in matters concerning which there are differences of opinion as to what is correct, for He is the All-Hearing, Ever-Responsive.
May Allah bless our Prophet Muhammad.”
And Allah knows best.