diff --git a/src/epochs.jl b/src/epochs.jl
index 181d3f1..24a4bd8 100644
--- a/src/epochs.jl
+++ b/src/epochs.jl
@@ -124,6 +124,10 @@ for f in (:year, :month, :day, :hour, :minute, :second, :millisecond)
     @eval Dates.$f(epoch::CDFDateTime) = Dates.$f(DateTime(epoch))
 end
 
+Epoch(s::AbstractString) = Epoch(DateTime(s))
+Epoch16(s::AbstractString) = Epoch16(DateTime(s))
+TT2000(s::AbstractString) = TT2000(DateTime(s))
+
 Dates.value(epoch::Epoch) = epoch.instant
 Dates.value(epoch::Epoch16) = ComplexF64(epoch.seconds, epoch.picoseconds)
 Dates.value(epoch::TT2000) = epoch.instant.value
diff --git a/src/loading/attribute.jl b/src/loading/attribute.jl
index 3405bc9..67f47f3 100644
--- a/src/loading/attribute.jl
+++ b/src/loading/attribute.jl
@@ -64,12 +64,14 @@ function vattrib(cdf::CDFDataset, varnum::Integer)
     for offset in offsets
         is_global(buffer, offset, RecordSizeType) && continue
         adr = ADR(buffer, offset, RecordSizeType)
-        @assert min(adr.AgrEDRhead, adr.AzEDRhead) == 0
-        head = max(adr.AgrEDRhead, adr.AzEDRhead)
-        found = _search_aedr_entries(buffer, head, RecordSizeType, cdf_encoding, varnum)
-        isnothing(found) && continue
-        name = String(adr.Name)
-        attributes[name] = _get_attributes(name, found, cdf)
+        for head in (adr.AgrEDRhead, adr.AzEDRhead)
+            head == 0 && continue
+            found = _search_aedr_entries(buffer, head, RecordSizeType, cdf_encoding, varnum)
+            isnothing(found) && continue
+            name = String(adr.Name)
+            attributes[name] = _get_attributes(name, found, cdf)
+            break
+        end
     end
     return attributes
 end
@@ -101,10 +103,13 @@ function vattrib(cdf, varnum, name)
         is_global(buffer, offset, RecordSizeType) && continue
         adr = ADR(buffer, offset, RecordSizeType)
         adr.Name != name_bytes && continue
-        @assert min(adr.AgrEDRhead, adr.AzEDRhead) == 0
-        head = max(adr.AgrEDRhead, adr.AzEDRhead)
-        value = _search_aedr_entries(buffer, head, RecordSizeType, cdf_encoding, varnum)
-        return _get_attributes(name, value, cdf)
+        for head in (adr.AgrEDRhead, adr.AzEDRhead)
+            head == 0 && continue
+            found = _search_aedr_entries(buffer, head, RecordSizeType, cdf_encoding, varnum)
+            isnothing(found) && continue
+            return _get_attributes(name, found, cdf)
+        end
+        return nothing
     end
     return nothing
 end