diff --git a/src/cfdp/pdu/file_data.rs b/src/cfdp/pdu/file_data.rs
new file mode 100644
index 0000000..59a53ea
--- /dev/null
+++ b/src/cfdp/pdu/file_data.rs
@@ -0,0 +1,129 @@
+use crate::cfdp::pdu::{write_file_size, PduError, PduHeader};
+use crate::cfdp::{CrcFlag, LargeFileFlag, PduType, SegmentMetadataFlag};
+use crate::{ByteConversionError, SizeMissmatch};
+use num_enum::{IntoPrimitive, TryFromPrimitive};
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[repr(u8)]
+pub enum RecordContinuationState {
+    NoStartNoEnd = 0b00,
+    StartWithoutEnd = 0b01,
+    EndWithoutStart = 0b10,
+    StartAndEnd = 0b11,
+}
+
+pub struct SegmentMetadata<'seg_meta> {
+    record_continuation_state: RecordContinuationState,
+    seg_metadata_len: u8,
+    metadata: Option<&'seg_meta [u8]>,
+}
+
+impl SegmentMetadata<'_> {
+    pub fn written_len(&self) -> usize {
+        1 + self.seg_metadata_len as usize
+    }
+
+    pub fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, ByteConversionError> {
+        if buf.len() < self.written_len() {
+            return Err(ByteConversionError::ToSliceTooSmall(SizeMissmatch {
+                found: buf.len(),
+                expected: self.written_len(),
+            }));
+        }
+        buf[0] = ((self.record_continuation_state as u8) << 6) | self.seg_metadata_len;
+        if self.metadata.is_some() {
+            buf[1..].copy_from_slice(self.metadata.unwrap())
+        }
+        Ok(self.written_len())
+    }
+}
+
+pub struct FileDataPdu<'seg_meta, 'file_data> {
+    pdu_header: PduHeader,
+    segment_metadata: Option<SegmentMetadata<'seg_meta>>,
+    offset: u64,
+    file_data: &'file_data [u8],
+}
+
+impl<'seg_meta, 'file_data> FileDataPdu<'seg_meta, 'file_data> {
+    pub fn new_with_seg_metadata(
+        pdu_header: PduHeader,
+        segment_metadata: SegmentMetadata<'seg_meta>,
+        offset: u64,
+        file_data: &'file_data [u8],
+    ) -> Self {
+        Self::new_generic(pdu_header, Some(segment_metadata), offset, file_data)
+    }
+
+    pub fn new_no_seg_metadata(
+        pdu_header: PduHeader,
+        offset: u64,
+        file_data: &'file_data [u8],
+    ) -> Self {
+        Self::new_generic(pdu_header, None, offset, file_data)
+    }
+
+    pub fn new_generic(
+        mut pdu_header: PduHeader,
+        segment_metadata: Option<SegmentMetadata<'seg_meta>>,
+        offset: u64,
+        file_data: &'file_data [u8],
+    ) -> Self {
+        pdu_header.pdu_type = PduType::FileData;
+        if segment_metadata.is_some() {
+            pdu_header.seg_metadata_flag = SegmentMetadataFlag::Present;
+        }
+        Self {
+            pdu_header,
+            segment_metadata,
+            offset,
+            file_data,
+        }
+    }
+
+    pub fn written_len(&self) -> usize {
+        let mut len = self.pdu_header.header_len();
+        if self.segment_metadata.is_some() {
+            len += self.segment_metadata.as_ref().unwrap().written_len()
+        }
+        // Regular file size
+        len += core::mem::size_of::<u32>();
+        if self.pdu_header.pdu_conf.file_flag == LargeFileFlag::Large {
+            len += core::mem::size_of::<u32>();
+        }
+        len += self.file_data.len();
+        if self.pdu_header.pdu_conf.crc_flag == CrcFlag::WithCrc {
+            len += 2;
+        }
+        len
+    }
+
+    pub fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, PduError> {
+        if buf.len() < self.written_len() {
+            return Err(ByteConversionError::ToSliceTooSmall(SizeMissmatch {
+                found: buf.len(),
+                expected: self.written_len(),
+            })
+            .into());
+        }
+        let mut current_idx = self.pdu_header.write_to_bytes(buf)?;
+        if self.segment_metadata.is_some() {
+            current_idx += self
+                .segment_metadata
+                .as_ref()
+                .unwrap()
+                .write_to_bytes(&mut buf[current_idx..])?;
+        }
+        write_file_size(
+            &mut current_idx,
+            self.pdu_header.common_pdu_conf().file_flag,
+            self.offset,
+            buf,
+        )?;
+        buf[current_idx..current_idx + self.file_data.len()].copy_from_slice(self.file_data);
+        Ok(current_idx)
+    }
+}
diff --git a/src/cfdp/pdu/metadata.rs b/src/cfdp/pdu/metadata.rs
index dd6589c..ce0a70a 100644
--- a/src/cfdp/pdu/metadata.rs
+++ b/src/cfdp/pdu/metadata.rs
@@ -1,7 +1,7 @@
 use crate::cfdp::lv::Lv;
-use crate::cfdp::pdu::{FileDirectiveType, PduError, PduHeader};
+use crate::cfdp::pdu::{write_file_size, FileDirectiveType, PduError, PduHeader};
 use crate::cfdp::tlv::Tlv;
-use crate::cfdp::{ChecksumType, CrcFlag, LargeFileFlag};
+use crate::cfdp::{ChecksumType, CrcFlag, LargeFileFlag, PduType};
 use crate::{ByteConversionError, SizeMissmatch, CRC_CCITT_FALSE};
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
@@ -130,6 +130,7 @@ impl<'src_name, 'dest_name, 'opts> MetadataPdu<'src_name, 'dest_name, 'opts> {
         dest_file_name: Lv<'dest_name>,
         options: Option<&'opts [u8]>,
     ) -> Self {
+        pdu_header.pdu_type = PduType::FileDirective;
         let is_large_file = pdu_header.common_pdu_conf().file_flag == LargeFileFlag::Large;
         let has_crc = pdu_header.common_pdu_conf().crc_flag == CrcFlag::WithCrc;
         pdu_header.pdu_datafield_len =
@@ -213,18 +214,12 @@ impl<'src_name, 'dest_name, 'opts> MetadataPdu<'src_name, 'dest_name, 'opts> {
         buf[current_idx] = ((self.metadata_params.closure_requested as u8) << 7)
             | (self.metadata_params.checksum_type as u8);
         current_idx += 1;
-        if self.pdu_header.common_pdu_conf().file_flag == LargeFileFlag::Large {
-            buf[current_idx..current_idx + core::mem::size_of::<u64>()]
-                .copy_from_slice(&self.metadata_params.file_size.to_be_bytes());
-            current_idx += core::mem::size_of::<u64>()
-        } else {
-            if self.metadata_params.file_size > u32::MAX as u64 {
-                return Err(PduError::FileSizeTooLarge(self.metadata_params.file_size));
-            }
-            buf[current_idx..current_idx + core::mem::size_of::<u32>()]
-                .copy_from_slice(&(self.metadata_params.file_size as u32).to_be_bytes());
-            current_idx += core::mem::size_of::<u32>()
-        }
+        write_file_size(
+            &mut current_idx,
+            self.pdu_header.common_pdu_conf().file_flag,
+            self.metadata_params.file_size,
+            buf,
+        )?;
         current_idx += self
             .src_file_name
             .write_to_be_bytes(&mut buf[current_idx..])?;
@@ -318,7 +313,9 @@ pub mod tests {
     use crate::cfdp::pdu::tests::verify_raw_header;
     use crate::cfdp::pdu::{CommonPduConfig, FileDirectiveType, PduHeader};
     use crate::cfdp::tlv::{Tlv, TlvType};
-    use crate::cfdp::{ChecksumType, CrcFlag, LargeFileFlag};
+    use crate::cfdp::{
+        ChecksumType, CrcFlag, LargeFileFlag, PduType, SegmentMetadataFlag, SegmentationControl,
+    };
     use crate::util::UbfU8;
     use std::vec;
 
@@ -544,4 +541,21 @@ pub mod tests {
         }
         assert_eq!(accumulated_len, pdu_read_back.options().unwrap().len());
     }
+
+    #[test]
+    fn test_corrects_pdu_header() {
+        let pdu_header = PduHeader::new_for_file_data(
+            common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Normal),
+            0,
+            SegmentMetadataFlag::NotPresent,
+            SegmentationControl::NoRecordBoundaryPreservation,
+        );
+        let metadata_params = MetadataGenericParams::new(false, ChecksumType::Crc32, 10);
+        let src_filename = Lv::new_from_str(SRC_FILENAME).expect("Generating string LV failed");
+        let dest_filename =
+            Lv::new_from_str(DEST_FILENAME).expect("Generating destination LV failed");
+        let metadata_pdu =
+            MetadataPdu::new(pdu_header, metadata_params, src_filename, dest_filename);
+        assert_eq!(metadata_pdu.pdu_header().pdu_type(), PduType::FileDirective);
+    }
 }
diff --git a/src/cfdp/pdu/mod.rs b/src/cfdp/pdu/mod.rs
index 1643b5d..31fafb4 100644
--- a/src/cfdp/pdu/mod.rs
+++ b/src/cfdp/pdu/mod.rs
@@ -7,6 +7,7 @@ use core::fmt::{Display, Formatter};
 #[cfg(feature = "std")]
 use std::error::Error;
 
+pub mod file_data;
 pub mod metadata;
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, TryFromPrimitive, IntoPrimitive)]
@@ -442,6 +443,27 @@ impl PduHeader {
     }
 }
 
+pub(crate) fn write_file_size(
+    current_idx: &mut usize,
+    fss: LargeFileFlag,
+    file_size: u64,
+    buf: &mut [u8],
+) -> Result<(), PduError> {
+    if fss == LargeFileFlag::Large {
+        buf[*current_idx..*current_idx + core::mem::size_of::<u64>()]
+            .copy_from_slice(&file_size.to_be_bytes());
+        *current_idx += core::mem::size_of::<u64>()
+    } else {
+        if file_size > u32::MAX as u64 {
+            return Err(PduError::FileSizeTooLarge(file_size));
+        }
+        buf[*current_idx..*current_idx + core::mem::size_of::<u32>()]
+            .copy_from_slice(&(file_size as u32).to_be_bytes());
+        *current_idx += core::mem::size_of::<u32>()
+    }
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use crate::cfdp::pdu::{CommonPduConfig, PduError, PduHeader, FIXED_HEADER_LEN};